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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_10 | Pages 3 - 3
23 May 2024
Patel A Sivaprakasam M Reichert I Ahluwalia R Kavarthapu V
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Introduction

Charcot neuroarthropathy (CN) of foot and ankle presents significant challenges to the orthopaedic foot and ankle surgeon. Current treatment focuses on conservative management during the acute CN phase with offloading followed by deformity correction during the chronic phase. However, the deformity can progress in some feet despite optimal offloading resulting ulceration, infection, and limb loss. Our aim was to assess outcomes of primary surgical management with early reconstruction.

Methods

Between December 2011 and December 2019, 25 patients underwent operative intervention at our specialist diabetic foot unit for CN with progressive deformity and or instability despite advanced offloading. All had peripheral neuropathy, and the majority due to diabetes. Twenty-six feet were operated on in total - 14 during Eichenholtz stage 1 and 12 during stage 2. Fourteen of these were performed as single stage procedures, whereas 12 as two-stage reconstructions. These included isolated hindfoot reconstructions in seven, midfoot in four and combined in 14 feet. Mean age at the time of operation was 54. Preoperative ulceration was evident in 14 patients.


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_6 | Pages 39 - 39
2 May 2024
Saroha S Raheman F Jaiswal P Patel A
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In this study, we examined the impact of dual-mobility (DM) versus fixed-bearing (FB) implants on outcomes following total hip arthroplasty (THA), a common and successful operation. We examined all-cause revision, revision due to dislocation, postoperative complications and functional scores in patients undergoing primary and revision THA.

A systematic review was performed according to PRISMA guidelines, and was registered in PROSPERO (ID CRD42023403736). The Cochrane Library, Embase, MEDLINE, Web of Science, and Scopus were searched from inception to 12th March 2023. Eligible studies underwent meta-analysis and methodological assessment using the ROBINS-I tool. Data were pooled using a random-effects maximum-likelihood model.

Eight comparative, non-randomised studies involving 2,810 DM implants and 3,188 FB implants were included. In primary THA, the difference in all-cause revision was imprecise (OR 0.82, 95% CI 0.25–2.72), whilst the DM cohort had a statistically significant benefit in revision due to dislocation (OR 0.08, 95% CI 0.02–0.28). In revision THA, the DM cohort showed significant benefit in all-cause revision (OR 0.57, 95% CI 0.31–1.05) and revision due to dislocation (OR 0.14, 95% CI 0.04–0.53). DM implants were associated with a lower incidence of implant dislocation and infection. Functional outcome analysis was limited due to underreporting. No intraprosthetic dislocations were observed.

The results suggest that contemporary DM designs may be advantageous in reducing the risk of all-cause revision, revision due to dislocation, and postoperative complication incidence at mid-term follow-up. Further high-quality prospective studies are needed to evaluate the long-term performance of this design, especially in revision cases.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_13 | Pages 8 - 8
7 Aug 2023
Kaka A Shah A Yunus A Patel A Patel A
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Abstract

Introduction

Challenges in surgical training have led to the exploration of technologies such as augmented reality (AR), which present novel approaches to teaching orthopaedic procedures to medical students. The aim of this double-blinded randomised-controlled trial was to compare the validity and training effect of AR to traditional teaching on medical students’ understanding of total knee arthroplasty (TKA).

Methodology

Twenty medical students from 7 UK universities were randomised equally to either intervention or control groups. The control received a consultant-led teaching session and the intervention received training via Microsoft HoloLens, where surgeons were able to project virtual information over physical objects. Participants completed written knowledge and practical exams which were assessed by 2 orthopaedic consultants. Training superiority was established via 4 quantitative outcome measures: OSATS scores, a checklist of TKA-specific steps, procedural time, and written exam scores. Qualitative feedback was evaluated using a 5-point Likert scale.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_11 | Pages 40 - 40
7 Jun 2023
Edwards T Soussi D Gupta S Khan S Patel A Patil A Badri D Liddle A Cobb J Logishetty K
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Superior teamwork in the operating theatre is associated with improved technical performance and clinical outcomes. Yet modern rota patterns, workforce shortages, and increasing complexity of surgery, means that there is less familiarity between staff and the required choreography. Immersive Virtual Reality (iVR) can successfully train surgical staff individually, however iVR team training has yet to be investigated. We aimed to design a multiplayer iVR platform for anterior approach total hip arthroplasty (AA-THA) and assess if multiplayer iVR training was superior to single player training for acquisition of both technical and non-technical skills.

An iVR platform with choreographed roles for the surgeon and scrub nurse was developed using Cognitive Task Analysis. Forty participants were randomised to individual or team iVR training. Individually- trained participants practiced alongside virtual avatar counterparts, whilst teams trained live in pairs. Both groups underwent five iVR training sessions over 6-weeks. Subsequently, they underwent a real-life assessment in which they performed AA-THA on a high-fidelity model with real equipment in a simulated theatre. Teams performed together and individually trained participants were randomly paired up. Videos were marked by two blinded assessors recording the NOTSS, NOTECHS II and SPLINTS scores - validated technical and non-technical scores assessing surgeon and scrub nurse skills. Secondary outcomes were procedure time and number of technical errors.

Teams outperformed individually trained participants for non-technical skills in the real-world assessment (NOTSS 13.1 ± 1.5 vs 10.6 ± 1.6, p =0.002, NOTECHS-II score 51.7 ± 5.5 vs 42.3 ± 5.6, p=0.001 and SPLINTS 10 ± 1.2 vs 7.9 ± 1.6, p = 0.004). They completed the assessment 28.1% faster (27.2 minutes ± 5.5 vs 41.8 ±8.9, p<0.001), and made fewer than half the number of technical errors (10.4 ± 6.1 vs 22.6 ± 5.4, p<0.001).

Multiplayer training leads to faster surgery with fewer technical errors and the development of superior non-technical skills for anterior approach total hip arthroplasty. The convention of surgeons and nurses training separately, but undertaking real complex surgery together, can be supplanted by team training, delivered through immersive virtual reality.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_11 | Pages 18 - 18
7 Jun 2023
Schapira B Spanoudakis E Jaiswal P Patel A
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Surgical trainees are finding it increasingly more challenging to meet operative requirements and coupled with the effects of COVID-19, we face a future of insufficiently trained surgeons. As a result, virtual reality (VR) simulator training has become more prevalent and whilst more readily accepted in certain arthroscopic fields, its use in hip arthroscopy (HA) remains novel. This project aimed to validate VR high-fidelity HA simulation and assess its functional use in arthroscopic training.

Seventy-two participants were recruited to perform two basic arthroscopic tasks on a VR HA simulator, testing hip anatomy, scope manipulation and triangulation skills. They were stratified into novice (39) and experienced (33) groups based on previous arthroscopy experience. Metric parameters recorded from the simulator were used to assess construct validity. Face validity was evaluated using a Likert-style questionnaire. All recordings were reviewed by 2 HA experts for blinded ASSET score assessment.

Experienced participants were significantly faster in completing both tasks compared with novice participants (p<0.001). Experienced participants damaged the acetabular and femoral cartilage significantly less than novice participants (p=0.011) and were found to have significantly reduced path length of both camera and instrument across both tasks (p=0.001, p=0.007), demonstrating significantly greater movement economy. Total ASSET scores were significantly greater in experienced participants compared to novice participants (p=0.041) with excellent correlation between task time, cartilage damage, camera and instrument path length and corresponding ASSET score constituents. 62.5% of experienced participants reported a high degree of realism in all facets of external, technical and haptic experience with 94.4% advising further practice would improve their arthroscopic skills. There was a relative improvement of 43% in skill amongst all participants between task 1 and 2 (p<0.001).

This is the largest study to date validating the use of simulation in HA training. These results confirm significant construct and face validity, excellent agreement between objective measures and ASSET scores, significant improvement in skill with continued use and recommend VR simulation to be a valuable asset in HA training for all grades.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_8 | Pages 13 - 13
11 Apr 2023
Edwards T Gupta S Soussi D Patel A Khan S Liddle A Cobb J Logishetty K
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Current evidence suggests that superior surgical team performance is linked to fewer intra-operative errors, reductions in mortality and even improved patient outcomes. Virtual reality has demonstrated excellent efficacy in training surgeons and scrub nurses individually, however its impact on training teams is currently unknown. This study aimed to assess if training together (scrub nurse and surgeon) in an innovative multiplayer virtual reality program was superior to single player training for novices learning anterior approach total hip arthroplasty (AA-THA).

40 participants (20 novice surgeons (CT1-ST3 level) and 20 novice scrub nurses) were enrolled in this study and randomised to individual or team virtual reality training. Individually-trained participants played with virtual avatar counterparts, whilst teams trained live in pairs (surgeon and scrub nurse). Both groups underwent 5 VR training sessions over 6 weeks. Subsequently, they underwent a real-life assessment in which they performed AA-THA on a high-fidelity model with real equipment in a simulated operating theatre. Teams performed together and individually-trained participants were randomly paired up with a solo player of the opposite role. Videos of the assessment were marked by two blinded expert assessors. The primary outcome was team performance as graded by the validated NOTECHs II score. Secondary outcomes were procedure time and number of technical errors from an expert pre-defined protocol.

Teams outperformed individually-trained participants for non-technical skills in the real-world assessment (NOTECHS-II score 50.3 ± 6.04 vs 43.90 ± 5.90, p=0.0275). They completed the assessment 28.1% faster (31.22 minutes ±2.02 vs 43.43 ±2.71, p=0.01), and made close to half the number of technical errors when compared to the individual group (12.9 ± 8.3 vs 25.6 ± 6.1, p=0.001).

Multiplayer, team training appears to lead to faster surgery with fewer technical errors and the development of superior non-technical skills.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_7 | Pages 104 - 104
4 Apr 2023
Edwards T Khan S Patel A Gupta S Soussi D Liddle A Cobb J Logishetty K
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Evidence supporting the use of virtual reality (VR) training in orthopaedic procedures is rapidly growing. However, the impact of the timing of delivery of this training is yet to be tested. We aimed to investigate whether spaced VR training is more effective than massed VR training.

24 medical students with no hip arthroplasty experience were randomised to learning the direct anterior approach total hip arthroplasty using the same VR simulation, training either once-weekly or once-daily for four sessions. Participants underwent a baseline physical world assessment on a saw bone pelvis. The VR program recorded procedural errors, time, assistive prompts required and hand path length across four sessions. The VR and physical world assessments were repeated at one-week, one-month, and 3 months after the last training session.

Baseline characteristics between the groups were comparable (p > 0.05). The daily group demonstrated faster skills acquisition, reducing the median ± IQR number of procedural errors from 68 ± 67.05 (session one) to 7 ± 9.75 (session four), compared to the weekly group's improvement from 63 ± 27 (session one) to 13 ± 15.75 (session four), p < 0.001. The weekly group error count plateaued remaining at 14 ± 6.75 at one-week, 16.50 ± 16.25 at one-month and 26.45 ± 22 at 3-months, p < 0.05. However, the daily group showed poorer retention with error counts rising to 16 ± 12.25 at one-week, 17.50 ± 23 at one-month and 41.45 ± 26 at 3-months, p<0.01. A similar effect was noted for the number of assistive prompts required, procedural time and hand path length. In the real-world assessment, both groups significantly improved their acetabular component positioning accuracy, and these improvements were equally maintained (p<0.01).

Daily VR training facilitates faster skills acquisition; however weekly practice has superior skills retention.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_7 | Pages 90 - 90
4 Apr 2023
Sharma M Khanal P Patel N Patel A
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To investigate the utility of virtual reality (VR) simulators in improving surgical proficiency in Orthopaedic trainees for complex procedures and techniques.

Fifteen specialty surgeons attending a London Orthopaedic training course were randomised to either the VR (n = 7) or control group (n = 8). All participants were provided a study pack comprising an application manual and instructional video for the Trochanteric Femoral Nail Advanced (TFNA) procedure. The VR group underwent additional training for TFNA using the DePuy Synthes (Johnson and Johnson) VR simulator. All surgeons were then observed applying the TFNA in a Sawbones model and assessed by a blinded senior consultant using three metrics: time to completion, 22-item procedure checklist and 5-point global assessment scale.

Participant demographics for the VR and control groups were similar in context of age (mean [SD]: VR group, 31.0 [2.38] years; control group, 30.6 [2.39] years), gender (VR group, 5 [71%] men; control group, 8 [100%] men) and prior experience with TFNA (had applied TFNA as primary surgeon: VR group, 6 [86%]; control group, 7 [88%]). Although statistical significance was not reached, the VR group, on average, outperformed the control group on all three metrics. They completed the TFNA procedure faster (mean [SD]: 18.2 [2.16] minutes versus 19.78 [1.32] minutes; p<0.189), performed a greater percentage of steps correctly (79% versus 66%; p<0.189) and scored a higher percentage on the global assessment scale (75% versus 65%; p<0.232).

VR simulators offer a safe and accessible means for Orthopaedic trainees to prepare for and supplement their theatre-based experience. It is vital, therefore, to review and validate novel simulation-based systems and in turn facilitate their improvement. We intend to increase our sample size and expand this preliminary study through a second upcoming surgical course for Orthopaedic trainees in London.


Bone & Joint Open
Vol. 4, Issue 3 | Pages 129 - 137
1 Mar 2023
Patel A Edwards TC Jones G Liddle AD Cobb J Garner A

Aims

The metabolic equivalent of task (MET) score examines patient performance in relation to energy expenditure before and after knee arthroplasty. This study assesses its use in a knee arthroplasty population in comparison with the widely used Oxford Knee Score (OKS) and EuroQol five-dimension index (EQ-5D), which are reported to be limited by ceiling effects.

Methods

A total of 116 patients with OKS, EQ-5D, and MET scores before, and at least six months following, unilateral primary knee arthroplasty were identified from a database. Procedures were performed by a single surgeon between 2014 and 2019 consecutively. Scores were analyzed for normality, skewness, kurtosis, and the presence of ceiling/floor effects. Concurrent validity between the MET score, OKS, and EQ-5D was assessed using Spearman’s rank.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_16 | Pages 9 - 9
1 Dec 2021
Edwards T Soussi D Gupta S Patel A Liddle A Khan S Cobb J Logishetty K
Full Access

Abstract

Objectives

Non-technical skills including teamwork play a pivotal role in surgical outcomes. Virtual reality is effective at improving technical skills, however there is a paucity of evidence on team-based virtual reality (VR) training. This study aimed to assess if multiplayer virtual reality training was superior to solo training for acquisition of both technical and non-technical skills in learning the complex anterior approach total hip arthroplasty operation.

Methods

10 novice surgeons and 10 novice scrub nurses, were randomised to solo or team virtual reality training to perform anterior approach total hip arthroplasty. Solo participants trained with virtual avatar counterparts, whilst teams trained in pairs (surgeon and scrub nurse). Both groups underwent 5 VR training sessions over 6 weeks. Then, they underwent a real-life assessment in which they performed AA-THA on a high-fidelity model with real equipment in a simulated operating theatre. Teams performed together and solo participants were randomly paired up with a solo player of the opposite role. Videos of the assessment were marked by two blinded expert assessors. Outcomes were procedure time, procedural errors from an expert pre-defined protocol and acetabular component positioning. Non-technical skills were assessed using the NOTECHs II and NOTSS scores.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_16 | Pages 32 - 32
1 Dec 2021
Edwards T Khan S Patel A Gupta S Soussi D Liddle A Cobb J Logishetty K
Full Access

Abstract

Objectives

Evidence supporting the use of immersive virtual reality (iVR) training in orthopaedic procedures is rapidly growing. However, the impact of the timing of delivery of this training is yet to be tested. This study investigated whether spaced iVR training is more effective than massed iVR training for novices learning hip arthroplasty.

Methods

24 medical students with no hip arthroplasty experience were randomised to learning total hip arthroplasty using the same iVR simulation training either once-weekly or once-daily for four sessions. Participants underwent a baseline physical world assessment to orientate an acetabular component on a saw bone pelvis, and a baseline knowledge test. In iVR, we recorded procedural errors, time, numbers of prompts required and path lengths of the hands and head across 4 sessions. To assess skill retention, the iVR and baseline physical world assessments were repeated at one-week and one-month.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_1 | Pages 44 - 44
1 Feb 2021
Edwards T Patel A Szyszka B Coombs A Kucheria R Cobb J Logishetty K
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Background

Revision total knee arthroplasty (rTKA) is a high stakes procedure with complex equipment and multiple steps. For rTKA using the ATTUNE system revising femoral and tibial components with sleeves and stems, there are over 240 pieces of equipment that require correct assembly at the appropriate time. Due to changing teams, work rotas, and the infrequency of rTKR, scrub nurses may encounter these operations infrequently and often rely heavily on company representatives to guide them. In turn, this delays and interrupts surgical efficiency and can result in error. This study investigates the impact of a fully immersive virtual reality (VR) curriculum on training scrub nurses in technical skills and knowledge of performing a complex rTKA, to improve efficiency and reduce error.

Method

Ten orthopaedic scrub nurses were recruited and trained in four VR sessions over a 4-week period. Each VR session involved a guided mode, where participants were taught the steps of rTKA surgery by the simulator in a simulated operating theatre. The latter 3 sessions involved a guided mode followed by an unguided VR assessment. Outcome measures in the unguided assessment were related to procedural sequence, duration of surgery and efficiency of movement. Transfer of skills was assessed during a pre-training and post-training assessment, where participants completed multi-step instrument selection and assembly using the real equipment. A pre and post-training questionnaire assessed the participants knowledge, confidence and anxiety.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_4 | Pages 94 - 94
1 Apr 2018
Patel A Li L Qureshi A Deierl K
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Introduction

Hoffa fractures are rare, intra-articular fractures of the femoral condyle in the coronal plane and involving the weight-bearing surface of the distal femur. Surgical fixation is warranted to achieve stability, early mobilisation and satisfactory knee function.

We describe a unique type of Hoffa fracture in the coronal plane with sagittal split and intra-articular comminution. There is scant evidence in current literature with regards to surgical approaches, techniques and implants. We report of our case with a review of the literature.

Case report

A 40 year old male motorcyclist was involved in a high speed road traffic collision. X-rays confirmed displaced unicondylar fracture of the lateral femoral condyle. CT showed sagittal split of the Hoffa fragment and intra-articular comminution. MRI showed partial rupture of the anterior cruciate ligament. The patient underwent definitive surgical treatment via a midline skin incision and lateral parapatellar approach using cannulated screws, headless compression screws and anti-glide plate. Weightbearing was commenced at 8 weeks. Arthroscopy and adhesiolysis was performed at 12 weeks to improve range of motion. The patient was discharged at one year with a pain-free, functional knee.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_8 | Pages 26 - 26
1 Apr 2017
Li L Patel A Jundi H Parmar H
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Background

Focal resurfacing can treat localised articular damage of the knee not appropriate for arthroplasty or biological repair. Independent results on these implants are limited. We previously published early results showing significantly improved Knee Injury & Osteoarthritis Outcome Score (KOOS4) without complication or re-operation, demonstrating this system gives good analgesia and functional improvement in selected patients. We present long-term follow-up of these patients.

Methods

We prospectively evaluated medium- to long-term results in patients with localised, full-thickness articular cartilage defects of the knee undergoing HemiCAP resurfacing. All procedures were performed by one consultant surgeon. Post-operative rehabilitation was standardised. Outcome measures were KOOS4 score, visual analogue score (VAS), Kellgren and Lawrence arthritis grade, and re-operation rates.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_8 | Pages 65 - 65
1 Apr 2017
Patel A Li L Rashid A
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Background

Radial head fractures are the commonest fractures involving the elbow. The goals of treatment are to restore stability, preserve motion, and maintain the relative length of the radius. Fortunately, most simple uncomplicated fractures can be treated non-operatively. Choosing between fixation and radial head replacement for comminuted fractures remains difficult. Excision of radial head fractures is not an ideal option in unstable elbow injuries. The purpose of this systematic review was to search for and critically appraise articles directly comparing functional outcomes and complications for fixation (open reduction internal fixation, ORIF) versus arthroplasty for comminuted radial head fractures (Mason type 3) in adults.

Method

A comprehensive search of Medline, Embase and Cochrane databases using specific search terms and limits was conducted. Strict eligibility criteria were applied to stringently screen resultant articles. Three comparative studies were identified and reviewed.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_1 | Pages 75 - 75
1 Jan 2017
Anand A Li L Trigkilidas D Patel A
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We performed a systematic review to compare outcomes of cemented versus uncemented trapezio-metacarpal joint (TMCJ) replacement for treatment of base-of-thumb arthritis.

We assessed improvements in pain and function, range of movement (ROM), strength, complications and need for revision surgery. A thorough literature search was performed. A total of 481 studies were identified from the literature search (179 Medline, 253 Embase, 27 CINAHL, 22 Cochrane). Of 43 relevant titles 28 were selected for full-text review after assessment of the abstracts. Duplicate studies were removed. 18 studies met inclusion criteria on full-text review. All studies were of level IV evidence. There were no randomised controlled trials or meta-analyses. The studies were critically appraised using a validated scoring system.

Most studies reported good outcomes for pain and strength, and functional outcome was comparable for both groups. ROM was generally improved for both prosthetic types, however statistical calculation was lacking in many studies. Trapezial component loosening was the main problem for both cemented and uncemented prostheses, however radiological loosening did not necessarily correlate with implant failure.

This systematic review has found that both cemented and uncemented replacements generally give good outcomes for the treatment of TMCJ arthritis, however young, male, patients with manual occupations and with disease in the dominant hand and patients with poor trapezial bone stock appear to be at higher risk for implant failure due to cup loosening. We recommend the construction of a joint registry to record implantation and revision rates.


The Bone & Joint Journal
Vol. 98-B, Issue 9 | Pages 1234 - 1239
1 Sep 2016
Yu HM Malhotra K Butler JS Patel A Sewell MD Li YZ Molloy S

Aims

Patients with multiple myeloma (MM) develop deposits in the spine which may lead to vertebral compression fractures (VCFs). Our aim was to establish which spinopelvic parameters are associated with the greatest disability in patients with spinal myeloma and VCFs.

Patients and Methods

We performed a retrospective cross-sectional review of 148 consecutive patients (87 male, 61 female) with spinal myeloma and analysed correlations between spinopelvic parameters and patient-reported outcome scores. The mean age of the patients was 65.5 years (37 to 91) and the mean number of vertebrae involved was 3.7 (1 to 15).


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 14 - 14
1 May 2016
Manalo J Patel A Goyal N Fitz D Talati R Stulberg S
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Introduction

Three anatomic landmarks are typically used to estimate proper femoral component rotation in total knee arthroplasty: the transepicondylar axis (TEA), Whiteside's line, and the posterior condylar axis (PCA). Previous studies have shown that the presence of tibia vara may be accompanied by a hyperplastic posteromedial femoral condyle, which affects the relationship between the PCA and the TEA. The purpose of this study was to determine the relationship of tibia vara with the PCA.

Methods

Two hundred and forty-eight knees underwent planning for total knee arthroplasty with MRI. The MRI was used to characterize the relationship between the transepicondylar axis and the posterior condylar axis. Long-leg standing films (LLSF) were obtained to evaluate the medial proximal tibial angle. The MPTA is defined as the medial angle formed between a line along the anatomic axis of the tibia and a line along the tibial plateau.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 27 - 27
1 May 2016
Carroll K Patel A Carli A Cross M Jerabek S Mayman D
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Introduction

While implant designs and surgical techniques have improved in total knee arthroplasty (TKA), approximately 20% of patients remain dissatisfied. The purpose of this study was to determine if reproduction of anatomic preoperative measurements correlated to improved clinical outcomes in TKA.

Methods

We retrospectively reviewed95 patients (106 knees) who underwent a TKA between 2012 −2013 with a minimum of one year follow-up. All patients had a pre and post-operative SF-12 and WOMAC scores. Pre and 6 week post-operative radiographs were reviewed to compare restoration of coronal plane alignment, maintenance of joint line obliquity, and maintenance of tibial varus. Coronal alignment was defined as the angle formed between the mechanical axis of the femur and the the tibia. Joint line obliquity was defined as the angle between the mechanical axis of the limb and the line which best parallels the joint space at the knee. Tibial varus was compared between the preoperative proximal lateral tibial angle and the angle formed by the mechanical axis of the tibia and tibial component postoperatively.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 13 - 13
1 May 2016
Manalo J Patel A Goyal N Fitz D Talati R Stulberg S
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Introduction

Current techniques in total knee arthroplasty aim to restore the coronal mechanical axis to neutral. Preoperative planning has historically been based on long-leg standing films (LLSF) which allow surgeons to plan bony resection and soft tissue releases. However, LSSF can be prone to error if malrotated. Recently, patient-specific guides (PSG) utilizing supine magnetic resonance imaging (sMRI) have become an accepted technique for preoperative planning. In this study we sought to compare the degree of coronal deformity using LLSF and sMRI.

Methods

Two hundred thirty knees underwent planning for total knee arthroplasty with sMRI and LLSF. Coronal plane deformity was determined based on the femoral-tibial angle (FTA) as defined by the angle formed between a line from the center of the femoral head to the intercondylar notch and a line from the middle of the tibial spines to the middle of the ankle joint. Mechanical axis values from the sMRI were compared with values obtained from LLSF


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_4 | Pages 53 - 53
1 Jan 2016
Talati R Alvi H Sweeney P Patel A Stulberg SD
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Introduction

Total knee arthroplasty is effective for the management of osteoarthritis of the knee. Conventional techniques utilizing manual instrumentation (MI) make use of intramedullary femoral guides and either extramedullary or intramedullary tibial guides. While MI techniques can achieve excellent results in the majority of patients, those with ipsilateral hardware, post-traumatic deformity or abnormal anatomy may be technically more challenging, resulting in poorer outcomes. Computer-assisted navigation (CAN) is an alternative that utilizes fixed trackers and anatomic registration points, foregoing the need for intramedullary guides. This technique has been shown to yield excellent results including superior alignment outcomes compared to MI with fewer outliers. However, studies report a high learning curve, increased expenses and increased operative times. As a result, few surgeons are trained and comfortable utilizing CAN. Patient-specific instrumentation is an alternative innovation for total knee arthroplasty. Custom guide blocks are fabricated based on a patient's unique anatomy, allowing for the benefits of CAN but without the increased operative times or the high learning curve. In this study we sought to evaluate the accuracy of PSI techniques in patients with previous ipsilateral hardware of the femur.

Methods

After reviewing our database of 300 PSI total knee arthroplasty patients, 16 were identified (10 male, 6 female) using the Zimmer NexGen Patient Specific Instrumentation System. Fourteen patients included in the study had a preexisting total hip arthroplasty on the ipsilateral side [Figure 1], 1 had a sliding hip screw, and 1 patient had a cephalomedullary nail. Postoperative mechanical axis alignment measurements were performed using plain long-standing radiographs [Figure 2]. The American Knee Society Score was used to evaluate clinical outcomes postoperatively.


The Bone & Joint Journal
Vol. 97-B, Issue 12 | Pages 1683 - 1692
1 Dec 2015
Patel A James SL Davies AM Botchu R

The widespread use of MRI has revolutionised the diagnostic process for spinal disorders. A typical protocol for spinal MRI includes T1 and T2 weighted sequences in both axial and sagittal planes. While such an imaging protocol is appropriate to detect pathological processes in the vast majority of patients, a number of additional sequences and advanced techniques are emerging. The purpose of the article is to discuss both established techniques that are gaining popularity in the field of spinal imaging and to introduce some of the more novel ‘advanced’ MRI sequences with examples to highlight their potential uses.

Cite this article: Bone Joint J 2015;97-B:1683–92.


The Bone & Joint Journal
Vol. 97-B, Issue 9 | Pages 1170 - 1174
1 Sep 2015
Patel A Pavlou G Ahmad RA Toms A

In England and Wales more than 175 000 hip and knee arthroplasties were performed in 2012. There continues to be a steady increase in the demand for joint arthroplasty because of population demographics and improving survivorship. Inevitably though the absolute number of periprosthetic infections will probably increase with severe consequences on healthcare provision. The Department of Health and the Health Protection Agency in United Kingdom established a Surgical Site Infection surveillance service (SSISS) in 1997 to undertake surveillance of surgical site infections. In 2004 mandatory reporting was introduced for one quarter of each year. There has been a wide variation in reporting rates with variable engagement with the process. The aim of this article is to improve surgeon awareness of the process and emphasise the importance of engaging with SSISS to improve the quality and type of data submitted. In Exeter we have been improving our practice by engaging with SSISS. Orthopaedic surgeons need to take ownership of the data that are submitted to ensure these are accurate and comprehensive.

Cite this article: Bone Joint J 2015;97-B:1170–4.


The Bone & Joint Journal
Vol. 97-B, Issue 8 | Pages 1076 - 1081
1 Aug 2015
Patel A Pavlou G Mújica-Mota RE Toms AD

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are recognised and proven interventions for patients with advanced arthritis. Studies to date have demonstrated a steady increase in the requirement for primary and revision procedures. Projected estimates made for the United States show that by 2030 the demand for primary TKA will grow by 673% and for revision TKA by 601% from the level in 2005. For THA the projected estimates are 174% and 137% for primary and revision surgery, respectively. The purpose of this study was to see if those predictions were similar for England and Wales using data from the National Joint Registry and the Office of National Statistics.

Analysis of data for England and Wales suggest that by 2030, the volume of primary and revision TKAs will have increased by 117% and 332%, respectively between 2012 and 2030. The data for the United States translates to a 306% cumulative rate of increase between 2012 and 2030 for revision surgery, which is similar to our predictions for England and Wales.

The predictions from the United States for primary TKA were similar to our upper limit projections. For THA, we predicted an increase of 134% and 31% for primary and revision hip surgery, respectively.

Our model has limitations, however, it highlights the economic burden of arthroplasty in the future in England and Wales as a real and unaddressed problem. This will have significant implications for the provision of health care and the management of orthopaedic services in the future.

Cite this article: Bone Joint J 2015;97-B:1076–1081.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_15 | Pages 33 - 33
1 Oct 2014
Molloy S Butler J Patel A Bentom A Jassim S Sewell M Aftab S
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To assess the clinical and radiologic outcome of MM patients with thoracic spine involvement and concomitant pathologic sternal fractures with a resultant severe sagittal plane deformity.

A prospective cohort study (n=391) was performed over a 7-year period at a national tertiary referral centre for the management of multiple myeloma with spinal involvement. Clinical, serological and pathologic variables, radiologic findings, treatment strategies and outcome measures were prospectively collected. Pre-treatment and post-treatment clinical outcome measures utilised included EQ-5D, VAS, ODI and RMD scoring systems.

13 MM patients presented with a severe symptomatic progressive sagittal plane deformity with a history of pathologic thoracic compression fractures and concomitant pathologic sternal fracture. All patients with concomitant sternal fractures displayed the radiographic features and spinopelvic parameters of positive sagittal malalignment and attempted clinical compensation. All patients had poor health related quality of life measures when assessed.

Pathologic sternal fracture in a MM patient with thoracic compression fractures is a risk factor for the development of a severe thoracic kyphotic deformity and sagittal malalignment. This has been demonstrated to be associated with a very poor health related quality of life.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_15 | Pages 30 - 30
1 Oct 2014
Molloy S Aftab S Patel A Butler J Balaji V Wilson L Lee R
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To assess screw malposition rates and complications associated with pedicle screw insertion using 3D navigation technology.

A retrospective study was undertaken for all cases where O-arm® and StealthStation® systems were used over a 2-year period. The primary outcome measure was return to theatre rates for pedicle screw malposition.

A total of 938 screws were inserted (934 thoracolumbar and 4 cervical), and 103 patients underwent spinal fixation using O-arm® and StealthStation® navigation. 64 were revision cases and 39 primary cases. Average number of levels was 4.6. There were a total of 10 complications: 3 infections, 1 DVT, 1 PE, 1 fast atrial fibrillation (AF), 1 screw malposition, 1 non-union, 1 undisplaced vertebral body fracture and 1 nerve root compression following osteotomy. The percentage return to theatre for screw malposition using 3D navigation was 1% of patients and 0.1% of pedicle screws. No patients developed permanent neurological compromise.

These systems provide accuracy that is comparable to traditional 2D fluoroscopic techniques. We advocate their use in the safe insertion of pedicle screws in complex revision deformity cases where original anatomical landmarks are absent or obscured. We also believe that radiation exposure is considerably less with navigation especially in these complex and revision cases.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 96 - 96
1 Jul 2014
Geurts J Patel A Helmrich U Hirschmann M Müller-Gerbl M Valderrabano V Hügle T
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Summary Statement

Cross-talk between cells from immune and bone system might play a role in molecular regulation of subchondral bone sclerosis in osteoarthritis. Macrophages, B-lymphocytes and tartrate-resistant acid phosphatase activity are specifically increased in sclerotic subchondral bone of patients with knee osteoarthritis.

Background

Recent investigations have provided substantial evidence that distinct molecular and morphological changes in subchondral bone tissue, most notably sclerosis, play an active and important role in the pathogenesis of OA. The cellular and molecular regulation of this pathological process remains poorly understood. Here, we investigated whether osteoimmunology, the reciprocal signaling between cells from the immune and bone system, is involved in OA subchondral bone sclerosis.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_2 | Pages 21 - 21
1 Jan 2014
Ribee H Bhalla A Patel A Johnson B Leah J Bailey A Chapman C Bing A Hill S Laing P Makwana N Thomason K Marquis C
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Introduction:

Plantar Fasciitis is an extremely common and challenging problem that presents itself to foot and ankle practitioners. Many different treatment modalities are available for this condition, with little proven benefit. ECSWT was approved for use by the FDA for the treatment of chronic proximal plantar fasciitis in 2002 and NICE published guidance in 2009 recommending its use in refractory cases.

Methods:

Patients who diagnosed with ultrasound scan, and for whom other treatments were unsuccessful, underwent treatment on an outpatient basis. They had three 4–5 minute sessions, once a week. A Spectrum machine was used delivering 10 Hz waves in 500 preset pulses at 2 bar pressure, followed by 2000 preset pulses at 2.5 bar pressure. Pre- and 3 month post-treatment pain levels were recorded using a 10 point Visual Analogue Scale.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 539 - 539
1 Dec 2013
Alvi H Luo M Talati R Sweeney P Patel A Yaffe M Stulberg SD
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Introduction:

Total knee arthroplasty (TKA) is an effective operation for the management of osteoarthritis of the knee. Conventional technique utilizing manual instrumentation (MI) allows for reproducible and accurate execution of the procedure. The most common techniques make use of intramedullary femoral guides and either extrameduallary or intrameduallary tibial guides. While these methods can achieve excellent results in the majority of patients, those with ipsilateral hardware, post-traumatic deformity or abnormal anatomy may preclude the accurate use of these techniques.

Patient-specific instrumentation (PSI) is an alternative innovation for total knee arthroplasty. Utilizing magnetic resonance imaging (MRI) or computed tomography (CT), custom guide blocks are fabricated based on a patient's unique anatomy. This allows for the benefits of computer assisted navigation (CAN) but without the increased operative times or the high learning curve associated with it. Furthermore it allows the use of familiar cutting blocks and guides to check the accuracy of the PSI guide blocks. In this study we sought to evaluate the accuracy of PSI techniques in patients with previous ipsilateral hardware, which would make the use of MI technically challenging and possibly subject to inaccuracy.

Methods:

After reviewing our database of 300 PSI total knee arthroplasty patients, 16 patients were identified (10 male, 6 female) using the Zimmer NexGen Patient Specific Instrumentation System. Fourteen patients included in the study had a preexisting total hip arthroplasty on the ipsilateral side, 1 had a preexisting sliding hip screw, and 1 patient had a preexisting cephalomedullary nail. Postoperative mechanical axis alignment measurements were performed using plain long-standing radiographs. The American Knee Society Score was used to evaluate clinical outcomes postoperatively.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 67 - 67
1 Dec 2013
Goyal N Patel A Yaffe M Luo M Stulberg SD
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Introduction:

Patient specific instrumentation (PSI) generates customized guides from a magnetic resonance imaging based preoperative plan for use in total knee arthroplasty (TKA). PSI software must be able to accommodate differences in implant design. The purpose of the present study was to determine whether any differences in the accuracy of limb alignment, component alignment, component sizing, or bony resection could be identified in patients undergoing PSI TKA with identical PSI software and one of two different implant systems.

Methods:

In this case-control study, two different implant systems from the same manufacturer were evaluated in 37 consecutive PSI TKA (Group 1) and 123 consecutive PSI TKA (Group 2) performed by a single surgeon. A third group (Group 3) consisted of 12 consecutive TKA performed with manual instrumentation and the same implant system as Group 1. Identical software was used to generate a preoperative plan from which planned limb alignment, component alignment, component sizes, and bony resection were determined. Intraoperatively, actual component sizes, bony resection, and recut frequency were determined. Long-standing and lateral radiographs were obtained preoperatively and 4-weeks postoperatively to evaluate limb and component alignment.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 176 - 176
1 Dec 2013
Stulberg SD Alvi H Talati R Patel A Yaffe M
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Introduction:

Patient specific instrumentation (PSI) is an innovative technology in total knee arthroplasty. With the use of a preoperative MRI or CT scan, custom guide blocks are individually manufactured for each patient. Contrary to other TKA technologies such as computer-assisted surgery, PSI utilizes measured resection technique rather than a primarily ligament balancing technique. This has the potential to negatively affect the operating surgeon's ability to achieve optimal soft tissue balancing, which is especially critical in patients with severe lower extremity malalignment. Despite early research suggesting that PSI is accurate, has a low learning curve, and can reduce OR time, it remains unclear whether a surgeon using PSI can achieve optimal soft tissue balancing using a measured resection technique. The purpose of this study is to evaluate the efficacy of PSI in patients with severe preoperative limb alignment deformities.

Methods:

Fifty PSI total knee arthroplasties were performed on 46 patients (21 male, 25 female) using the Zimmer NexGen Patient Specific Instrumentation system. Each patient included in the study had a minimum preoperative deformity of at least 10° varus or valgus measured on preoperative long leg standing radiographs, Zimmer preoperative software or both. Forty-three of the included knees had a varus deformity and 7 had a valgus deformity. Preoperative mechanical axis alignment measurements were obtained using the PSI preoperative planning software and were manually calculated using pre-operative long leg standing radiographs. Postoperative mechanical axis alignment measurements were calculated using plain long leg standing radiographs. The Knee Society Scoring System was used to evaluate clinical and functional outcomes at 1 to 6 months postoperatively.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_28 | Pages 106 - 106
1 Aug 2013
Alvi H Talati R Patel A Yaffe M Stulberg S
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Introduction

Patient specific instrumentation (PSI) is an innovative technology in total knee arthroplasty (TKA). With the use of a preoperative MRI or CT scan, custom guide blocks are individually manufactured for each patient. Contrary to other TKA technologies such as computer-assisted surgery, PSI utilises measured resection technique rather than a primarily ligament balancing technique. This has the potential to negatively affect the operating surgeon's ability to achieve optimal soft tissue balancing, which is especially critical in patients with severe lower extremity malalignment. Despite early research suggesting that PSI is accurate, has a low learning curve, and can reduce operating room time, it remains unclear whether a surgeon using PSI can achieve optimal soft tissue balancing using a measured resection technique. The purpose of this study is to evaluate the efficacy of PSI in patients with severe preoperative limb alignment deformities.

Methods

Fifty PSI total knee arthroplasties were performed on 46 patients (21 male, 25 female) using the Zimmer NexGen Patient Specific Instrumentation system. Each patient included in the study had a minimum preoperative deformity of at least 10° varus or valgus measured on preoperative long leg standing radiographs, Zimmer preoperative software or both. Forty-three of the included knees had a varus deformity and 7 had a valgus deformity. Preoperative mechanical axis alignment measurements were obtained using the PSI preoperative planning software and were manually calculated using preoperative long leg standing radiographs. Postoperative mechanical axis alignment measurements were calculated using plain long leg standing radiographs. The Knee Society Scoring System was used to evaluate clinical and functional outcomes at 1 to 6 months postoperatively.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 301 - 301
1 Mar 2013
Patel A Patel R Thomas D Stulberg SD Bauer T
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Introduction

Modular femoral necks have shown promising clinical results in total hip arthroplasty (THA) to optimize offset, rotation, and leg length. Given the wide variety of proximal femoral morphology, fine-tuning these kinematic parameters can help decrease femoroacetabular impingement, decrease wear rates and help prevent dislocations. Yet, additional implant junctions introduce additional mechanisms of failure. We present two patients who developed an abnormal soft tissue reaction consistent with a metal hypersensitivity reaction at a modular femoral neck/stem junction requiring revision arthroplasty.

Methods

Two patients underwent THA for primary osteoarthritis with the same series of components: 50 mm shell, a 36 mm highly-crosslinked polyethylene liner, uncemented titanium alloy modular stem with a 130 degree Cobalt Chromium (CoCr) modular femoral neck, and 36 mm CoCr head with a +5-mm offset. Patient 1 was a 63 year-old female who had an uneventful post-operative course but presented seven months later with progressive pain in the left hip. Patient 2 was an 80 year-old female who did well post-operatively, but presented with limp and persistent pain at 10 months post-op.

An initial evaluation of a painful THA to rule out aseptic loosening, infection, mal-positioning, loosening and osteolysis included radiographs, lab work (CBC, ESR, CRP, Cobalt & Chromium levels) and Metal Artifact Reduction Sequence (MARS) MRI.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 362 - 362
1 Mar 2013
Yaffe M Patel A Luo M Chan P Cayo M Stulberg SD
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Introduction

Patient specific instruments (PSI) and computer-assisted surgery (CAS) are innovative technologies that offer the potential to improve the accuracy and reproducibility with which a total knee arthroplasty (TKA) is performed. It has not been established whether clinical, functional, or radiographic outcomes between PSI, CAS, and manual TKA differ in the hands of an experienced TKA surgeon. The purpose of this study was to evaluate clinical, functional and radiographic outcomes between TKA performed with PSI, CAS, and manual instruments at short-term follow-up. Our hypothesis was that at early follow-up, we would be unable to elucidate any significant differences between the groups using the most commonly utilized outcomes measures.

Methods

40 PSI, 38 CAS, and 40 manual TKA were performed by a single surgeon. The groups were similar in regards to age, sex, and preoperative diagnosis. The Knee Society Scoring System was used to evaluate patient clinical and functional outcome scores preoperatively and at 1 and 6 months postoperatively. Long-standing AP radiographs were obtained pre and postoperative to evaluate mechanical axis alignment.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 300 - 300
1 Mar 2013
Patel A Yaffe M Talati R Meisles J Ghate R Stulberg SD
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Introduction

Proper femoral component rotation is a crucial factor in successful total knee arthroplasty (TKA). Femoral component rotation using anatomic landmarks has traditionally been established by referencing the transepicondylar axis (TEA), Whiteside's Line (WSL), or the posterior condylar axis (PCA). TEA is thought to best approximate the flexion-axis of the knee, however WSL or PCA are commonly used as surrogates of the TEA in the operating room due to their accessibility. The relationship of these anatomic landmarks has been previously investigated in anatomic and computed tomography based studies. The relatively few knees evaluated have limited the power of these studies. Patient Specific Instrumentation (PSI) utilizing magnetic resonance imaging (MRI) is an emerging technology in total knee replacement. The purpose of this study was to use magnetic resonance imaging based planning software to assess the relationship of WSL and PCA to the TEA and to determine if the relationships were influenced by the magnitude of the pre-operative coronal deformity.

Methods

Five hundred sixty total knee replacements were performed in 510 patients utilizing PSI. The Materialize preoperative planning software was utilized to determine the rotational relationships of TEA, WSL, and PCA (Fig 1). The coronal plane deformity of each patient was also evaluated utilizing the MRI-based imaging and planning software.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_1 | Pages 108 - 108
1 Jan 2013
Patel A Anand A Alam M Anand B
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Background

Both-bone diaphyseal forearm fractures constitute up to 5.4% of all fractures in children under 16 years of age in the United Kingdom. Most can be managed with closed reduction and cast immobilisation. Surgical fixation options include flexible intramedullary nailing and plating. However, the optimal method is controversial.

Objectives

The main purpose of this study was to systematically search for and critically appraise articles comparing functional outcomes, radiographic outcomes and complications of nailing and plating for both-bone diaphyseal forearm fractures in children.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_1 | Pages 226 - 226
1 Jan 2013
Patel A Anand A Anand B Alam M
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Introduction

Indications for the use of external fixation include damage control orthopaedics, definitive fracture treatment, deformity correction and leg lengthening. Despite many advances in the development of external fixation techniques, pin-tract infection and loosening are still significant complications. They are the most commonly occurring complications during limb lengthening using external fixation, with some studies reporting an incidence of up to 80%.

Objectives

The main aim of this systematic review was to investigate HA-coated versus uncoated external fixator pins used in patients undergoing leg lengthening and determine benefits in terms of pin loosening, infection and loss of reduction/malunion.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLI | Pages 96 - 96
1 Sep 2012
van Dijck S Young S Patel A Zhu M Bevan W Tomlinson M
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Acute achilles tendon ruptures are increasing in incidence and occur in 18 per 100 000 people per year, however there remains a lack of consensus on the best treatment of acute ruptures. Randomised studies comparing operative versus non-operative treatment show operative treatment to have a significantly lower re-rupture rate, but these studies have generally used non-weight bearing casts in the non-operative group.

Recent series utilizing more aggressive non-operative protocols with early weight-bearing have noted a far lower incidence of re-rupture, with rates approaching those of operative management. Weight bearing casts may also have the advantages of convenience and an earlier return to work, and the purpose of this study was to compare outcomes of traditional casts versus Bohler-iron equipped weight-bearing casts in the treatment of acute Achilles tendon ruptures.

83 patients with acute Achilles tendon ruptures were recruited from three Auckland centres over a 2 year period. Patients were randomised within one week of injury to receive either a weight-bearing cast with a Bohler iron or a traditional non weight-bearing cast. A set treatment protocol was used, with a total cast time of eight weeks. Patients underwent detailed muscle dynamometry testing at 6 months, with further follow up at 1 year and at study completion. Primary outcomes assessed were patient satisfaction, time to return to work, and overall re-rupture rates. Secondary outcomes included return to sports, ankle pain and stiffness, footwear restrictions, and patient satisfaction.

There were no significant differences in patient demographics or activity levels prior to treatment. At follow up, 1 patient (2%) in the Bohler iron group and 2 patients (5%) in the non weight bearing group sustained re-ruptures (p=0.62). There was a trend toward an earlier return to work in the weight-bearing group, with 58% versus 43% returning to work within 4 weeks, but the difference was not significant. 63% of patients in the weight bearing group reported freedom from pain at 12 months compared to 51 % in the non weight bearing group. There were no statistically significant differences in Leppilahti scores, patient satisfaction, or return to sports between groups.

Weight-bearing casts in the non-operative treatment of Achilles tendon ruptures appear to offer outcomes that are at least equivalent to outcomes of non-weight bearing casts. The overall rerupture rate in this study is low, supporting the continued use of initial non-operative management in the treatment of acute ruptures.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 143 - 143
1 Sep 2012
Korduba L Loving L Klein R De Luise M Patel A Kester M
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INTRODUCTION

Many studies have looked at the effects of titanium tibial baseplates compared to cobalt chrome baseplates on backside wear. However, the surface finish of the materials is usually different (polished/unpolished) [1,2]. Backside wear may be a function not only of tray material but also of the locking mechanism. The purpose of this study was to evaluate the wear performance of conventional polyethylene inserts when mated with titanium tibial trays or cobalt chrome tibial trays that both have non-polished topside surfaces.

MATERIALS AND METHODS

Three titanium (Ti) trays were used along with three cobalt chrome (CoCr) trays. The Ti trays underwent Type II anodization prior to testing. All trays were Triathlon® design (Stryker Orthopaedics, Mahwah, NJ). Tibial inserts were manufactured from GUR 1020 conventional polyethylene then vacuum/flush packaged and sterilized in nitrogen (30 kGy). Appropriate sized CoCr femoral components articulated against the tibial inserts (Triathlon®, Stryker Orthopaedics, Mahwah, NJ).

Surface roughness of the tibial trays was taken prior to testing using white light interferometry (Zygo Corp, Middlefield, CT). A 6-station knee simulator (MTS, Eden Prairie, MN) was used for testing. Two phases were conducted. The first phase used a normal walking profile, as dictated by ISO 14243-3 [3]. The second phase used waveforms created specifically for stair climbing kinematics. Testing was conducted at a frequency of 1 Hz for 2 million cycles for each test with a lubricant of Alpha Calf Fraction serum (Hyclone Labs, Logan, UT) diluted to 50% with a pH-balanced 20-mMole solution of deionized water and EDTA (protein level = 20 g/l) [4]. The serum solution was replaced and inserts were weighed for gravimetric wear at least every 0.5 million cycles. Standard test protocols were used for cleaning, weighing and assessing the wear loss of the tibial inserts [5]. Soak control specimens were used to correct for fluid absorption with weight loss data converted to volumetric data (by material density). Statistical analysis was performed using the Student's t-test (p<0.05).


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 36 - 36
1 Sep 2012
Jacofsky D D'Alessio J Patel A Kester M
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INTRODUCTION

Recent studies indicated that the knee has a single flexion/extension axis but debated the location of this axis. The relationship of the flexion/extension axis in the coronal plane to the mechanical axis has received little attention. The purpose of this study was to investigate the relationship of the various axes and references with respect to the mechanical axis in the coronal plane

MATERIALS AND METHODS

Subjects were prospectively scanned into a Virtual Bone Database (Stryker Orthopaedics, Mahwah, NJ). Database is a collection of body CT scans from subjects collected globally. Only CT Scans that met the following qualifications were accepted: ≤1 mm voxels and had slice thickness that was equal to the spacing between the slices (≤ 1.0mm).

For each CT Scan, a frontal plane was created through the 2 most posterior points of the medial/lateral condyles and the most posterior point of the trochanter. Then, a transverse plane was created perpendicular to the frontal plane and bisects the 2 most distal points on the medial/lateral condyles. Finally, a saggital plane was created that was perpendicular to the frontal and transversal planes.

The following axes were identified: Mechanical Axis of the Femur (MAF) (line between the center of the femoral head and the center of the knee sulcus); Transepicondylar Axis Posterior Cylindrical Axis (PCA) (line between the Medial/Lateral Condylar Circle – best fit circle to three points identified on surface).

Measurements made: Angle of MAF and the Joint-Line (Femoral Joint Angle), Angle of the MAF and the Transepicondylar Axis (Femoral TE Angle), and Angle of the MAF and the Posterior Cylindrical Axis (Femoral PC angle). Angles measuring 90° were neutral or perpendicular to the MAF. Angles measured <90° were valgus and >90° were varus.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 519 - 519
1 Sep 2012
Ahmad M Sivaraman A Rai A Patel A
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Background

Distal tibial metaphyseal fractures pose many complexities. This study assessed the outcomes of distal tibial fractures treated with percutaneously inserted medial locking plates.

Methods

Eighteen patients were selected based on the fracture pattern and classified using the AO classification and stabilised with an AO medial tibial locking plate. Time to fracture union, complications and outcomes were assessed with the American Orthopaedic Foot and Ankle Society ankle score at 12 months.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 113 - 113
1 Sep 2012
Mont M Dethmers D McElroy M Johnson A Patel A Kester M
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Summary

Single use instrumentation had a significant reduction on OR Turnover time and instrument setup/clean up time compared to traditional instrumentation.

Introduction

Recently, focus has shifted to improving OR efficiency by surgeons and hospital admin. The purpose of this study was to determine the effect of traditional instrumentation vs. single use instrumentation (SUI) on OR efficiency in navigated primary TKA.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 141 - 141
1 Sep 2012
Patel R Puri L Patel A Albarillo M
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Introduction

Joint reconstruction remains a successful and popular surgery with advances in approaches, implants and techniques continually forthcoming. Various methods of skin closure exist to address issues in efficiency, aesthetics, and barrier to infection. While subcuticular skin closure techniques offer an aesthetic advantage to conventional skin stapling, no measurable differences have been reported. Furthermore, newer barbed sutures, such as the V-loc absorbable suture, theoretically distribute tension evenly through the wound and help decrease knot-related complications. To our knowledge, no literature exists on the rate of wound complications in joint arthroplasty with the use of V-loc suture for skin closure. We hypothesize that despite theoretical gains, skin closure with a V-loc (Covidien, Mansfield, MA) absorbable suture should be performed with caution.

Methods & Materials

A retrospective chart review was conducted of 278 consecutive primary joint reconstruction cases performed by a single surgeon in 12 months from July 2009 through June 2010. Pre-operative history & physical reports were evaluated for co-morbidities (i.e diabetes mellitus), smoking status and body mass index (BMI). Operative dictations by the attending surgeon provided information on the surgical procedure, use of drain, wound closure technique and type of suture/staple used for skin closure. Skin was closed by the primary surgeon and his chief resident. Wounds were closed via staple gun or subcuticular stitch (3-0 Biosyn vs V-Loc) in a consecutive manner, depending on the surgeon's preference in that period. Post-operative clinic notes were reviewed to determine the occurrence of wound complications, issuance of antibiotic prescriptions, or return to the operating room. The cohort consisted of 106 males and 161 females at an average age of 63 years (range: 18–92). Overall, there were 153 procedures at the knee (including TKA, uni-compartmental arthroplasty, patello-femoral arthroplasty) and 125 procedures at the hip (including THA and hemi-arthroplasty).


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 142 - 142
1 Sep 2012
Patel A Williams J Travers C Stulberg SD
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Introduction

It is thought that socioeconomic status and cultural upbringing influence the patient based outcomes of total joint arthroplasty. Previous studies have shown that patients in a lower socioeconomic class had surgery at an earlier age, increased comorbidities, increased severity of symptoms at presentation, and less satisfaction with the outcome. The purpose of this study was to compare the 1) reasons for undergoing total joint replacement and 2) satisfaction with the outcome among patients in different cultures and socioeconomic categories. We hypothesized that the overall reasons for undergoing surgery would be similar among all groups.

Method

Patients undergoing total hip or knee arthroplasty were divided into groups based on their country of residence and socioeconomic status. The patients were asked to rank their reasons for undergoing surgery preoperatively from 1 to 4 according to importance. They were also asked to state how much relief of pain or improvement in function they expected to obtain. They were then asked to complete a questionnaire assessing their satisfaction with surgery 6 months post-operatively. These results were then compared across the three groups.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 221 - 221
1 Sep 2012
Yaffe M McCoy B Patel A Stulberg SD
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Introduction

Computer-assisted surgery (CAS) is a tool developed to allow accurate limb and implant alignment in TKA. The strength of the technology is that it allows the surgeon to assess soft tissue balance and ligament laxity in flexion and extension. The accuracy of this ligament balancing technology depends upon an accurate determination of femoral component size. This size is established with intraoperative surface registration techniques. Customized instrumentation (CI) is a measured resection technique in which component size is established on preoperative 3D MRI reconstructions. The purpose of this study is to determine how these two computer-based technologies compare with regard to the accuracy with which femoral component size is established in TKA.

Methods

67 TKA were performed using CI and 30 TKA were performed using CAS by a single surgeon. CI-predicted and CAS-predicted femoral component size were compared to actual component selection. The process by which CI and CAS perform an anatomic registration was evaluated.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 139 - 139
1 Sep 2012
Patel A Yaffe M McCoy B Stulberg SD
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Introduction

Most surgeons utilize one of three axis options in conventional total knee arthroplasty (TKA), the transepicondylar axis (TEA), Whiteside's line (WSL) or the posterior condylar axis (PCA) with an external rotation correction factor. Each option has limitations and no clear algorithm has been determined for which option to use and when. Many surgeons believe the TEA to be the gold standard for determining rotation however it can be difficult to access intraoperatively. WSL and PCA have been used as surrogates for determining axial rotation in conventional TKA but may also be prone to error. MRI based preoperative planning systems overcome intraoperative limitations while accounting for the individual anatomy of each patient, thus helping optimize femoral component rotation. The goal of this study was to examine if coronal plane deformity had any effect on the relationship of conventional referencing options such as WSL and PCA to the TEA.

Methods

Utilizing a preoperative planning software based on MRI, we compared the preoperative posterior femoral condyle resections for three different axis options in 176 TKA. The difference in bone resection amount was used to determine the rotational differences between the axis options in all knees. Assuming that the TEA was the ideal rotational axis, we compared the TEA to both WSL and PCA. A 1-sample t-test and paired t-test were then used to determine if there was a significant rotational difference between the various axis options when accounting for degree and direction of preoperative deformity in the coronal plane.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 91 - 91
1 Sep 2012
Korduba L Le K Herrera L Essner A Patel A Kester M Hept J
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INTRODUCTION

For cementless TKA, highly crosslinked UHWMPE is traditionally used with modular components because of manufacturing and sterilization complexities of monoblock metal-backed components. However, it would be very useful to have a highly crosslinked UHMWPE monoblock metal-backed cementless component to address historical clinical issues. The purpose of this study was to evaluate the wear properties of a unique process for achieving a monoblock metal-backed cementless component featuring highly crosslinked polyethylene to standard highly crosslinked UHWMPE.

MATERIALS AND METHODS

The knee system used for testing consisted of cobalt chrome femoral components and tibial trays (Triathlon®, Stryker Orthopaedics, Mahwah, NJ). Modular tibial inserts were machined from GUR 1020 polyethylene that was irradiated to 30 kGy and annealed three times (Modular, n=5) (X3, Stryker Orthopaedics, Mahwah, NJ). Monoblock tibias were direct compression molded to a metal substrate and then irradiated to 30 kGy and annealed three times. For the purposes of this test, the polyethylene was removed from the monoblock component and machined into a standard tibial insert (Monoblock, n=5).

A 6-station knee simulator was utilized for testing (MTS, Eden Prairie, MN). All motion and loading was computer controlled and waveforms followed ISO 14243-3 [1]. Testing was conducted at a frequency of 1 Hz for 3 million cycles. The lubricant used was Alpha Calf Fraction serum (Hyclone Labs, Logan, UT) diluted to 50% with a pH-balanced 20-mMole solution of deionized water and EDTA [2]. The serum solution was replaced and inserts were weighed for gravimetric wear at least every 0.5 million cycles. Standard test protocols were used for cleaning, weighing and assessing the wear loss of the tibial inserts [3]. Soak control specimens were used to correct for fluid absorption with weight loss data converted to volumetric data (by material density). Statistical analysis was performed using the Student's t-test with significance determined at the 95% confidence level (p < 0.05).


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 102 - 102
1 Sep 2012
Leibowitz E Logan S Schmidig G Schinski J Kester M Patel A
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Traditional instrumentation relies on rigid IM rods to determine the distal femoral resection which influences size and orientation of the femoral component. Anterior femoral bowing may unexpectedly affect implant sizing. The purpose of this study was to determine the sensitivity of a flexible rod to the femoral anterior bow versus a traditional rod.

A database of 93 Asian bone models from CT images was utilized. The bones were subdivided into those having proximal third, distal third, or overall femoral bows. Only the latter group was selected for further analysis, which consisted of 54 with an average bow of 98cm (±20cm). The rigid and flexible rods were placed iteratively so that the proximal portion of the rod touched the anterior cortical-cancellous boundary and no portion of the rod protruded through that boundary. The flexible rod was allowed to flex, as a substantially thin central portion flexes exclusively in the sagittal plane. The relative angle difference between the position of the flexible and rigid rod were calculated.

Three femura were chosen from the subset with bows of 123cm, 100cm and 78cm. The femura showed differences between the rigid and flexible rod of 7.5°, 4.5° while no significant angle measured for the smallest bow. Implants were virtually assembled onto the bones and the greatest bowed femur's component reduced one size from the rigid to the flexible rod orientation.

The results of this study show that higher bowed femura yielded larger angular deviations between rigid and flexible rods. For higher bowed femura, the flexible rod allows smaller components to be implanted. The flexible rod serves the same purpose as a conventional rod by defining the distal valgus orientation but allows component orientation in the sagittal plane closer to the femoral bow.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVII | Pages 47 - 47
1 Jun 2012
Miller N Justice CM Marosy B Patel A Swindle K
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Introduction

Idiopathic scoliosis (IS) has been associated with several genetic loci in varying study populations, reflecting the disorder's genetic complexity. One region of interest is on chromosome 17, flanking regions linked to neurofibromatosis type 1 (NF1). This region is of particular relevance because the most common osseous manifestation in NF1 is scoliosis (10–30% of patients). This alludes to a potential genetic correlation within this region affecting spinal development or stability. The objective of this research is to identify candidate genes within this region that are statistically linked to IS.

Methods

An initial population of IS families recruited through approval by the institutional review board (202 families; 1198 individuals) had DNA harvested from blood, and underwent genomic screening, finemapping, and statistical analyses. We identified a specific familial subset: families with males having undergone surgery for scoliosis (17 families, 147 individuals). The initial genome-wide scan indicated that this subset was linked to chromosome 17q.11.2. The most prominent marker, D17s975, (p=0·0003) at 25.12 Mb is adjacent to the NF1 deletional region. We then analysed a custom panel of single-nucleotide polymorphisms (SNPs) extending from 18·30–31·47 Mb for linkage through Taqman SNP assay protocol. With allele specific fluorescent tags, allelic discrimination was done with real-time PCR.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IX | Pages 56 - 56
1 Mar 2012
Arumilli B Ng A Oyekanmi F Patel A Ellis D Hirst P
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Background

The cemented mobile bearing metal backed low contact stress patellofemoral arthroplasty (LCS PFA) is a newer design belonging to the second generation of inlay type implant, based on the more successful knee arthroplasty model. The advantage is the patella can articulate with the trochlear implant as well as the femoral component of a total knee replacement (TKR).

Patients

This series is a cohort of 21 patients who underwent 24 (3 bilateral) unicompartmental PFA replacements for isolated patellofemoral osteoarthritis. We have used the mobile bearing LCS PFA in all of them. There were 3 males and 18 females. Average age was 51(40-58) years. The Oxford Knee score was used to assess the results.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IV | Pages 147 - 147
1 Mar 2012
Costa M Patel A Donell S
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Background

Shockwave therapy has been shown to induce osteoneogenesis in animal models. The mechanism of action is unclear, but experimental evidence suggests micro-fracture formation and increased blood flow as the most likely explanation. Several reports from Europe have suggested good results from the treatment of delayed fracture union with shock-waves. We present the results of a randomised double-blind placebo-controlled pilot study.

Method

Fourteen patients with clinically and radiologically confirmed delayed union of long-bones consented to enter the trial. The treatment group had a single application of 3000 high-energy shockwaves using the Stortz SLK unit with image intensifier control. The control group had the exactly the same treatment but with an ‘air-gap’ interposition to create a placebo-shockwave. Each patient was followed-up with serial radiographs as well as visual analogue pain scores and EuroQol assessments. All of the patients were reviewed for a minimum of three years post treatment.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 485 - 485
1 Nov 2011
Pollintine P Harrison S Patel A Tilley D Miles A Gheduzzi S
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Introduction: Vertebroplasty is used to treat painful osteoporotic vertebral fractures, and involves transpedicular injection of bone cement into the fractured vertebral body. During injection, the fluid cement begins to “harden” to a solid, enabling it to support mechanical load. But the mechanical efficacy of vertebroplasty can be improved by using cements which disperse evenly throughout the vertebral body during injection (1). We hypothesise that a better cement dispersion is obtained with cements that have a slower viscosity increase during hardening. We test this using a numerical model.

Methods: A computer model mimicking the plate- and rod-like morphologies of cancellous bone was loaded into a commercial fluid dynamics package (CFX). During injection, viscosity increased linearly with time to simulate the hardening behaviour of the cement (2). The rate of viscosity increase was altered to mimic the hardening behaviour of 5 different cements, with the rates of increase chosen to encompass the hardening behaviour of commercial vertebroplasty cements (1). Simulations were run for 13 seconds, with cement injection at 1.5 mm/s. Cement dispersion was quantified by the proportion of marrow replaced by cement during injection. Injection pressure was also recorded.

Results: Injection pressure increased with time (p< 0.001), and maximum pressure correlated with the rate of viscosity increase (r2=0.7). The proportion of marrow replaced at the end of the experiment was inversely proportional to the rate of viscosity increase (r2=0.85). Cements with a rapidly increasing viscosity do not fully infiltrate regions of bone with plate-like morphologies, leading to a poorer cement dispersion.

Conclusion: Cements with slower hardening characteristics are dispersed more evenly throughout cancellous bone. Such cements may provide safer and more effective vertebroplasty procedures.

Conflicts of Interest: None

Source of Funding: Bupa Foundation


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_I | Pages 26 - 26
1 Jan 2011
Davis B Jani B Patel A
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Printed plain radiographs have traditionally been the method of image transfer between hospitals, but the advent of digital imaging has revolutionised modern day radiology. It is now commonplace for compact discs to be used as the transport media for digital images, the theoretical advantages being ease of transport and storage, integration with PACS systems and the ability to perform image manipulation. However, in our tertiary referral centre for pelvic and acetabular trauma, we noted problems with digital image transfer using this method.

We examined the last 25 compact discs sent to our unit for functionality on 3 separate computers. Only 17/25 discs loaded on all computers, and 2 discs failed to load on any computer. 9 of the remaining 23 discs did not allow image manipulation, and 1 disc would not allow retrieval of all the contained images. 5 of the 23 discs took longer than 5 minutes to retrieve the contained images. In summary, we classed 10 of the 25 discs as acceptable. Patient transfer to our unit was not delayed, but 4 patients underwent repeat CT scans due to incomplete imaging

Digital technology has made great advances into medical imaging. Standardisation using the DICOM format for image creation has attempted to eliminate issues of compatibility, but variation in software used to produce and view images can still vary from these standards. Technical errors in the creation of discs should be eliminated at source, and it is mandatory that referring units check the functionality of discs before they are sent. In this way, the potential for delay to transfer and subsequent repeat exposure to ionising radiation can be avoided.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_I | Pages 36 - 36
1 Jan 2011
Kanabar P Patel A
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Our aim was to analyse radiological outcome of proximal humerus fractures treated with Philos plate and to assess its usefulness in treatment of malunion and non-union.

Seventy-seven patients were treated with Philos plate (24 men and 53 women). Mean age was 61 years (15–88). There were 66 acute fractures, 6 nonunion, 4 mal-union and one periprosthetic fracture. Acute fractures included 29 two part, 30 three part and five 4 part fractures. Seven had associated dislocation. There were two head splitting fractures. Deltopectoral approach was used in all. No acute fractures were bonegrafted however all nonunions had bonegraft.

Postoperative radiographs were available for review for 59. Average union time was 12 weeks (8–24). Satisfactory union occurred in 51 (86.4%). Twenty-three (39 %) fractures had inadequate reduction. Malplacement of plate was observed in 25 (42%) leading to significant malunion in 11.8%. Satisfactory union was occurred in all of last 30 patients. Nonunion occurred in 2 with infection in one. Other complications included screw penetration into glenohumeral joint, avascular necrosis, screw backing out and tuberosity detachment. Philos plate fixation was used for treatment of 6 nonunions, 4 malunions and one periprosthetic fracture with satisfactory outcome in all.

Relatively high rate of complications was observed in early cases in this series. This could be attributed to the steep learning curve with this technique. Emphasis should be put on careful and adequate reduction of fracture and optimal placement of plate (about 8 mm from the tip of tuberosity) to avoid impingement and to achieve correct screw placement in the humeral head.

In conclusion, Philos plate has been of benefit in management of complex fractures as well as management of non-union of proximal humerus. Quality of reduction and optimal placement of plate appear to be the two most important parameters for a successful outcome.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_I | Pages 23 - 23
1 Jan 2011
Patel A Jani B
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As part of the workup long length femur radiograph may be carried out pre-operatively in patients presenting with a proximal femur fracture in order to rule out distant metastasis in patients with a history of malignancy but also in some patients in whom a suspicion of possible distal abnormality is aroused by the configuration of the proximal fracture

Using our unit’s database we identified all patients (n=689) presenting with a proximal femoral fracture between Sept 2006 and August 2007 at the Norfolk and Norwich University hospital in Norwich.

Of 689 patients, 92 patients (13.2%) had long length femur radiograph performed before surgery. Indications included history of cancer (39), subtrochantric fractures (14), spontaneous fracture without any fall(2), paget s disease(1), early onset osteoporosis(1) while no clear indication was available in 35 patients. Five patients (5.5%) were found to have some abnormality. Three of the 39 patients with a history of previous cancer were found to have a distal femur metastasis. Two of the 35 patients where a clear indication was not apparent had abnormal findings: one patient had a distal femur infarction and another was found to have a distal femoral malunion. In both cases long leg films did not influence choice of implant. Of the 39 patients with a previous history of cancer, 24 had short implants (hemi-arthroplasty, intramedullary device, DHS), 14 had long implants and one patient died before the operation.

Long length femoral radiographs appear to be indicated in patients with a documented history of a cancer as it helps to decide whether to use a long or short implant. However in patients without a history of malignancy, long leg films were of no value in decision making even if the configuration of the fracture was suspicious.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 238 - 238
1 Mar 2010
Pollintine P Harrison S Patel A Tilley D Miles A Gheduzzi S
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Introduction: Vertebroplasty is increasingly used in the treatment of painful osteoporotic vertebral fractures, and involves transpedicular injection of bone cement into the fractured vertebral body. Effective infiltration of the vertebral body cancellous bone by the cement is determined by the cement viscosity, and by the permeability of the bone. However, it is unclear how permeability is influenced by regional variations in porosity and architecture of bone within the vertebral body. The aim of the present study was to investigate how permeability is influenced by porosity and architecture of cancellous bone mimics.

Methods: Cylindrical polyamide mimics of two types of cancellous bone structures were fabricated using selective laser sintering (SLS) techniques. Structure A had the rod-like vertical and horizontal trabeculae typical of the anterior vertebral body, while structure B had oblique trabeculae typical of the posterior-lateral vertebral body. Structure B had fewer trabeculae than A. Porosities of 80 and 90% were represented for both structures. Golden syrup, which has a viscosity similar to bone cement1, was injected into the mimics at a constant speed using a ram driven by a materials testing machine. Pressure drop measurements across the mimic, made using a differential pressure transducer, were obtained at five different injection speeds. Permeability of each mimic was calculated from these measurements2. Two more repeat permeability measurements were performed on each mimic.

Results: Repeat measurements were always within 12% of the mean value. For structure A the mean permeabilities were 1.26×10-7 and 1.82×10-7m2 for the 80 and the 90% porosity mimics respectively. The corresponding mean permeabilities for structure B were 1.92×10-7 and 2.86×10-7m2.

Discussion: These preliminary results indicate that higher permeabilities occur in structures with higher porosities, and with structures containing fewer trabeculae that are arranged obliquely. Since permeability is a determinant of cement infiltration, taking into account patient-specific bone architecture parameters may improve the safety and clinical outcome of vertebroplasty. Future experiments will clarify in more detail the architectural parameters that have greatest effect on permeability.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 133 - 133
1 Mar 2010
Taylor RM Bernero J Patel A Brodke D Khandkar A
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Background: Implantable grade silicon nitride (Si3N4), such as MC2 TM from Amedica, is an attractive alternative to the common bearing materials used today for spinal and orthopedic applications. Ceramic bearings used in total hip arthroplasty (THA) consist of a femoral head (ball) articulating inside an acetabular cup (socket); the ball and socket are made of alumina (Al2O3) or Al2O3-based composite materials such as zirconia toughened alumina. Extensive studies on the mechanical, imaging and tribological characteristics of MC2 for spinal implants have been conducted. This paper summarizes some of the results from these studies.

Methods: Si3N4 materials properties were evaluated per ASTM standards C-1161 for flexural strength and E-399 for toughness, using the single edge notched beam method. Strength was also measured after subjecting the ceramic to accelerated aging conditions. Imaging compatibility of the MC2, PEEK, titanium, cobalt-chromium (CoCr) and trabecular metal discs was determined under a variety of imaging methods, including MRI. Wear testing of Si3N4 acetabular cups articulating against Si3N4 and CoCr femoral heads was also conducted. Biocompatibility evaluation of the Si3N4 was conducted per ISO 10993 protocols.

Results: MC2 Si3N4 exhibits improved mechanical properties over modern Al2O3 and Al2O3-based composite THA bearings, with a flexural strength of 920 ± 70 MPa, a Weibull modulus of 19, and a fracture toughness of 10 ± 1 MPa.m1/2. Accelerated aging of Si3N4 did not adversely affect the flexural strength. The imaging comparison study showed that Si3N4 did not exhibit any MRI imaging artifacts similar to PEEK, but unlike the metallic materials used for spinal implants. In wear tests using a hip simulator, Si3N4 acetabular cups produced low volumetric wear when articulating against Si3N4 or CoCr femoral heads. The implantable grade Si3N4 material was also found to be biocompatible.

Conclusions: Si3N4 exhibits a superior combination of properties including strength, toughness, MRI compatibility, and wear resistance. This may allow spinal implants with an important combination of properties than hitherto possible, including a wider range of design options, improved anatomic fit and imaging compatibility. Additionally, spinal vertebral body replacement implants were tested in static and fatigue conditions per the ASTM F 2077 and have been cleared by the FDA. An MC2 Si3N4 based total cervical disc implant has been designed and is undergoing pre-clinical testing. The versatility of the MC2 Si3N4 ceramic may enable its use in total disc replacements owing to its combination of superior wear resistance and imaging compatibility.


Compared with general anaesthesia, brachial plexus (BP) anaesthesia improves patient satisfaction and accelerates hospital discharge after ambulatory hand surgery; however, variable success rates and typical onset times up to 30 minutes have limited its widespread use. Increasing availability of high-resolution portable ultrasound has renewed interest in more proximal approaches to the BP, previously thought to carry unacceptable risk. The aim of this study was to compare the onset times of ultrasound guided supraclavicular and infraclavicular BP block in patients undergoing ambulatory hand surgery.

With ethics committee approval, patients presenting for hand surgery were prospectively randomised to either supraclavicular (trunks/divisions) or infraclavicular (cords) BP block. A single experienced operator (MF) placed all blocks using ultrasound only guidance. A blinded observer (AP, SY) assessed pinprick sensory and motor block on 3-point scale (normal=2, reduced=1, absent=0) in the median, ulnar, radial and musculocutaneous nerve territories every five minutes, or until blocks were complete. A single general anaesthesia without influence from the unblended anaesthetist.

Of the first 27 patients recruited, block placement details and Intraoperative data are presented in There was a trend to faster onset times and higher success in group infraclavicular, however, this did not reach statistical significance.

Interim results are so far inconclusive for the superiority of one approach. Both techniques were well tolerated and had a high success rate for surgical anaesthesia.


The Journal of Bone & Joint Surgery British Volume
Vol. 90-B, Issue 11 | Pages 1401 - 1406
1 Nov 2008
Patel A Calfee RP Plante M Fischer SA Arcand N Born C

Methicillin-resistant Staphylococcus aureus (MRSA) has become a ubiquitous bacterium in both the hospital and community setting. There are two major subclassifications of MRSA, community-acquired and healthcare-acquired, each with differing pathogenicity and management. MRSA is increasingly responsible for infections in otherwise healthy, active adults. Local outbreaks affect both professional and amateur athletes and there is increasing public awareness of the issue. Health-acquired MRSA has major cost and outcome implications for patients and hospitals. The increasing prevalence and severity of MRSA means that the orthopaedic community should have a basic knowledge of the bacterium, its presentation and options for treatment.

This paper examines the evolution of MRSA, analyses the spectrum of diseases produced by this bacterium and presents current prevention and treatment strategies for orthopaedic infections from MRSA.


The Journal of Bone & Joint Surgery British Volume
Vol. 90-B, Issue 10 | Pages 1380 - 1381
1 Oct 2008
Patel A Calfee R Thakur N Eberson C

Iliacus haematoma is a relatively rare condition, which may cause a local compressive neuropathy. It is usually diagnosed in adults with haemophilia or those on anticoagulation treatment and may occur after trauma. We present the case of a healthy 15-year-old boy with a femoral neuropathy due to an iliacus haematoma which resolved following conservative treatment.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 300 - 301
1 Jul 2008
Patel A Albrizio M
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Introduction: Obesity is detrimental to the health of an individual, however does a high body mass index (BMI) actually determine post operative morbidity following hip replacement surgery?

Methods: 550 consecutive primary hip replacement patients were included in this study. Patients were followed up at four weeks, six weeks and one year following surgery. Any complication that the patient had was recorded and listed either as local or general. The complications were further sub divided into minor and major depending on the risk they posed to the patient or the joint.

Results: The average BMI of our patients was 28.3 (4.3). 56 (10%) patients had a complication following hip replacement surgery. The group who did not have any complications had an average BMI of 28.13 (SD=4.6) while the group who sustained complications had an average BMI of 29.46 (SD=5.8) with a p value of 0.104 (Student t-test). When BMI was grouped in values of 5 starting from < 25 and ending with > 35 the p value was 0.029 (chi square test). Odds ratios for grouped BMI varied from 0.086–1.61(95% CI 1.01–1.08) (p=0.086). Odds ratios for individual surgeons ranged from 0.96–2.41 (p=0.024)

Discussion: When we looked at the overall BMI there was no significant difference between the group who had a complication and the group who did not have a complication, however when the BMI was split into groups those patients in group 30–34 and 35+ experienced a higher rate of complications. The final odds of BMI was 1.05 (1.01,1.09). There was a higher complication rate in the groups other than the ideal BMI of 25–29, and even a fall in BMI caused an increase in the complication rates.

Conclusions: Obese individuals are at a higher risk of developing a complication following surgery, however the operating surgeon also has an influence on the complication rate following hip replacements.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_I | Pages 40 - 40
1 Mar 2006
Patel A Venkatesh B
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The authors would like to present a retrospective study conducted on 178 patients having undergone a hip replacement. The aim of this study was to look at the immediate and short-term complications of hip replacement in relation to the body mass index (BMI).

Patients ranging from age 49 to 90 were included in this study with an average age of 67.5. BMI ranged from 18 to 41. Length of stay ranged from 3 days to 76 days with an average of 11.5 days. Follow up of each patient included any wound complications, time to mobilisation and time to discharge. Operative blood loss and need to transfusion were also looked at. Blood loss was found to be from 150 mls to 2400 mls.

A large number of orthopaedic surgeons use a BMI value of 35 as the upper cut off point to refuse elective surgery. Using the Null hypothesis the authors wanted to prove that a higher BMI resulted in higher complication rates. Statistical analysis of the data however did not show a significant relationship between BMI and early complications in hip replacement surgery. Parameters measured had a higher relationship to individual surgeons rather than the BMI.

The authors would like to conclude that using the BMI as a predictor of a higher rate of short-term complications and refusing surgery to patients with a higher BMI is not justified.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 336 - 337
1 Sep 2005
Logan K Costa M Patel A
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Introduction and Aims: To evaluate the results of humeral nailing with the new Fixion inflatable humeral nail.

Method: We retrospectively studied 42 patients with acute humeral fractures (20), delayed and non-union (12) and pathological fractures (10), who where treated with an inflatable humeral nail and had a minimum follow-up of six months. Our primary outcome measures were clinical and radiological union. Secondary outcome measures were revision of the nail, screening time and operative time. We made a clinical assessment of the patients using the Constant score of the shoulder and a measure of health-related quality of life, using the EuroQol EQ-5D questionnaire.

Results: In patients with acute fractures 16/19 (84%) went on to clinical and radiological union (1/20 patients died four weeks post-operatively from bronchopneumonia). All of the patients with delayed and non-union of humeral fractures went on to clinical and radiological union. In the patients with pathological fractures, the nail provided good palliative symptom relief. Average screening time was 40.5 seconds (21–107). Average operative time was 71 minutes (26–142). Constant score of the shoulder had a median of 67 (SIQ 46.5–77.5) in the affected arm and 87 (SIQ 74–89) in the normal arm.

Conclusion: The treatment of humeral fractures using the inflatable intramedullary nail is a simple and safe technique, avoiding the time and complications associated with distal locking. Its seems to be an appropriate technique with excellent results in those patients with delayed and non-union of humeral fractures, and provides effective palliation in patients with pathological fractures. Its efficacy in patients with acute fractures is comparable to other intramedullary nails. In our experience, it is particularly effective in the multiply injured and the infirm because of the speed and ease of insertion.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_III | Pages 339 - 339
1 Mar 2004
Shah N Anderson A Patel A Donnell S
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Aims: The aim of this study was to þnd out if undisplaced displaced distal radial fractures require plaster immobilisation. Methods: In this prospective study, undisplaced distal radial fractures were divided into two groups; plaster immobilisation was used for one group while removable volar splint was used for the other group. Follow up was at six weeks, three months and six months. Patients were assessed by clinical examination, grip strength, radiological assessment, EQ-5D and a Short Form 12 questionnaire. Results: At 3 months, no difference was found between the two groups in clinical evaluation, radiological assessment, the functional outcome, grip strength, and visual analogue score for pain. Conclusions: We conclude that undisplaced distal radius fractures can probably be treated with out a plaster cast and put straight into wrist orthosis.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 339 - 339
1 Nov 2002
Breakwell L Deas M Patel A Patel S Harland S Stirling AJ
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Objective: To compare the presentation, diagnosis and treatment of spinal tuberculosis in two cities, one in the UK, and one in Malaysia

Design: Retrospective comparison over a five-year period from June 1995. The Centres studied were the Royal Orthopaedic and Queen Elizabeth Hospitals, Birmingham (UK), and the Kuala Lumpur General Hospital (KL), Malaysia.

Subjects: There were 80 patients (29 females, mean age 42) in the KL group, and 19 patients (8 females, mean age 45) in the UK group.

Outcome measures: Frankel grading before and after treatment were measured for both groups.

Results: KL patients had higher rates of immunocompromise, and had fewer spinal levels involved, 2.1 compared with 2.6 (p-−0.04). There were 65 procedures, 58 positive ZN stains, and 65 positive cultures as compared with 24, 2 and 9 in Birmingham respectively. Improvement in Frankel grading was seen in four patients in UK (5 grades), and in 17 patients in KL (29 grades).

Conclusions: Although the two groups exhibited similar demographics, the rate of immunocompromise-related tuberculosis, severity of neurological deficit, and type of surgery undertaken differed significantly. Reasons for the difficulty in identifying the tubercle bacillus in Birmingham are discussed.


The Journal of Bone & Joint Surgery British Volume
Vol. 73-B, Issue 2 | Pages 330 - 334
1 Mar 1991
Bridle S Patel A Bircher M Calvert P

We have prospectively compared the fixation of 100 intertrochanteric fractures of the proximal femur in elderly patients with random use of either a Dynamic Hip Screw (DHS) or a new intramedullary device, the Gamma nail. We found no difference in operating time, blood loss, wound complications, stay in hospital, place of eventual discharge, or the patients' mobility at final review. There was no difference in failure of proximal fixation: cut-out occurred in three cases with the DHS, and twice with the Gamma nail. However, in four cases fracture of the femur occurred close to the Gamma nail, requiring further major surgery. In the absence of these complications, union was seen by six months in both groups.


The Journal of Bone & Joint Surgery British Volume
Vol. 68-B, Issue 2 | Pages 182 - 184
1 Mar 1986
Signoret F Feron J Bonfait H Patel A

We report three patients in whom a fractured odontoid process was associated with a fracture of the superior articular process of the second cervical vertebra. Although there were no signs of neurological disorder, damage to the C1-C2 joint in all three patients made fusion necessary. Forced lateral flexion is suggested as the possible mechanism of injury.