Classifying trochlear dysplasia (TD) is useful to determine the treatment options for patients suffering from patellofemoral instability (PFI). There is no consensus on which classification system is more reliable and reproducible for the purpose of guiding clinicians’ management of PFI. There are also concerns about the validity of the Dejour Classification (DJC), which is the most widely used classification for TD, having only a fair reliability score. The Oswestry-Bristol Classification (OBC) is a recently proposed system of classification of TD, and the authors report a fair-to-good interobserver agreement and good-to-excellent intraobserver agreement in the assessment of TD. The aim of this study was to compare the reliability and reproducibility of these two classifications. In all, six assessors (four consultants and two registrars) independently evaluated 100 axial MRIs of the patellofemoral joint (PFJ) for TD and classified them according to OBC and DJC. These assessments were again repeated by all raters after four weeks. The inter- and intraobserver reliability scores were calculated using Cohen’s kappa and Cronbach’s α.Aims
Methods
Classifying trochlear dysplasia (TD) is useful to determine the treatment options for patients suffering from patellofemoral instability (PFI). There is no consensus on which classification system is more reliable and reproducible for this purpose to guide clinicians in order to treat PFI. There are also concerns about validity of the Dejour classification (DJC), which is the most widely used classification for TD, having only a fair reliability score. The Oswestry-Bristol classification (OBC) is a recently proposed system of classification of TD and the authors report a fair-to-good interobserver agreement and good-to-excellent intra-observer agreement in the assessment of TD. The aim of this study was to compare the reliability and reproducibility of these two classifications. 6 assessors (4 consultants and 2 registrars) independently evaluated 100 magnetic resonance axial images of the patella-femoral joint for TD and classified them according to OBC and DJC. These assessments were again repeated by all raters after 4 weeks. The inter and intra-observer reliability scores were calculated using Cohen's kappa and Cronbach's alpha. Both classifications showed good to excellent interobserver reliability with high alpha scores. The OBC classification showed a substantial intra-observer agreement (mean kappa 0.628)[p<0.005] whereas the DJC showed a moderate agreement (mean kappa 0.572) [p<0.005]. There was no significant difference in the kappa values when comparing the assessments by consultants to those by registrars, in either classification systems. This large study from a non-founding institute shows both classification systems to be reliable for classifying TD based on magnetic resonance axial images of the patella-femoral joint, with the simple to use OBC having a higher intra-observer reliability score compared to the DJC.
Positioning of the acetabular component in total hip arthroplasty has profound effects on the biomechanics, stability and wear of the prosthesis. Normal anatomical position in females is 57 degrees (50 – 67 degrees) inclination with 19 degrees (9 – 32 degrees) of anteversion, whilst in males 56 degrees of inclination (48 – 66 degrees) with 19 degrees (9 – 32 degrees) is normal. In total hip arthroplasty, inclination recommendation ranges from 30 – 50 degrees. The aim of this study was to radiographically measure acetabular component position in total hip arthroplasty and compare to normal values. The Widmer method was used by two independent observers to radiographically measure inclination in 522 patients using standard AP radiographs. Primary measures and variables were statistically analysed as was inter and intra observer reliability. All patients included within the study received total hip arthroplasty for age related degenerative changes to the hip. Operations were undertaken by 17 separate consultants or senior registrars under their care.Background
Method
We assessed the difference in hospital based and early clinical
outcomes between the direct anterior approach and the posterior
approach in patients who undergo total hip arthroplasty (THA). The outcome was assessed in 448 (203 males, 245 females) consecutive
patients undergoing unilateral primary THA after the implementation
of an ‘Enhanced Recovery’ pathway. In all, 265 patients (mean age:
71 years (49 to 89); 117 males and 148 females) had surgery using
the direct anterior approach (DAA) and 183 patients (mean age: 70
years (26 to 100); 86 males and 97 females) using a posterior approach.
The groups were compared for age, gender, American Society of Anesthesiologists
grade, body mass index, the side of the operation, pre-operative
Oxford Hip Score (OHS) and attendance at ‘Joint school’. Mean follow-up
was 18.1 months (one to 50).Aims
Patients and Methods
The Direct Anterior Approach (DAA) offers potential advantages of quicker rehabilitation compared to posterior approach THR. The aim of this study was to compare hospital based and early clinical outcomes between these two groups with utilisation of Enhanced Recovery After Surgery (ERAS) protocol. Prospectively collected data for both cohorts were matched for age, gender, ASA grade, BMI, operation side, Pre-operative Oxford Hip score (OHS) and attendance at multi-disciplinary joint school. The pain scores at 0,1,2,3 post-op days, the day of mobilization, inpatient duration, complications, 28 days readmission rates and OHS at 6 and 24 months were compared.Introduction
Patients/Materials & Methods
Infection after knee arthroplasty is a devastating complication. Our aim is to present our outcomes of treating infected knee replacements at a tertiary referral centre. We performed a consecutive, retrospective case series of all revision knee arthroplasty for infection between January 2006 and December 2008. Case notes were reviewed and data collated on the date and institution of primary arthroplasty, procedures undertaken at our institution, microbiology and bone loss post first stage, serological markers (C-reactive protein, ESR) prior to second stage and outcome. During this three year period we performed 430 knee revision operations. 51 were in the presence of deep chronic infection. 90% were referred from other hospitals. Overall infection was successfully eradicated in 69%. Nineteen patients underwent repeat two-stage and overall eleven (58%) patients had successful eradication of infection with multiple two-stages. Of these 47% had F3/T3, the highest grading of Anderson Orthopaedic Research Institute bone loss indicating no metaphyseal bone. A further 12% had bicondylar deficiency on the tibia and no femoral metaphyseal bone (F3/T2b). Multidrug resistance present in 69% and 47% were infected with multiple organisms. All members of the unsuccessful outcome group had at least one multidrug resistant organism compared to 43% in the successful cohort (P=0.0002). Multiple organisms are associated with an unsuccessful outcome (P=0.056). Serological markers were not significantly different between the successful and unsuccessful outcome groups. Where the referring hospital had attempted revision and failed, the chance of eradicating infection dropped from 75% to 58% and the rate of above knee amputation was twelve times higher (3% vs. 36%). Custom constrained, rotating hinge prostheses enable aggressive soft tissue debridement including ligaments. Successful two-stage requires a multidisciplinary approach including tissue viability nurses, microbiologists and plastic surgeons. Where units lack revision expertise this series suggests early referral increases the chance of limb salvage.
Plasma levels of cobalt and chromium ions and
Metal Artefact Reduction Sequence (MARS)-MRI scans were performed
on patients with 209 consecutive, unilateral, symptomatic metal-on-metal
(MoM) hip arthroplasties. There was wide variation in plasma cobalt
and chromium levels, and MARS-MRI scans were positive for adverse reaction
to metal debris (ARMD) in 84 hips (40%). There was a significant
difference in the median plasma cobalt and chromium levels between
those with positive and negative MARS-MRI scans (p <
0.001).
Compared with MARS-MRI as the potential reference standard for the
diagnosis of ARMD, the sensitivity of metal ion analysis for cobalt
or chromium with a cut-off of >
7 µg/l was 57%. The specificity was
65%, positive predictive value was 52% and the negative predictive
value was 69% in symptomatic patients. A lowered threshold of >
3.5 µg/l for cobalt and chromium ion levels improved the sensitivity
and negative predictive value to 86% and 74% but at the expense
of specificity (27%) and positive predictive value (44%). Metal ion analysis is not recommended as a sole indirect screening
test in the surveillance of symptomatic patients with a MoM arthroplasty.
The investigating clinicians should have a low threshold for obtaining
cross-sectional imaging in these patients, even in the presence
of low plasma metal ion levels.
Late stage medial unicompartmental osteoarthritic disease of the knee can be treated by either Total Knee Replacement (TKR) or Unicompartmental Replacement (UKR). As a precursor to the TOPKAT study this work tested the postulate that individual surgeons show high variation in the choice of treatment for individual patients. Four surgeons representing four different levels of expertise or familiarity with partial knee replacement (UKR design centre knee surgeon, specialist knee surgeon, arthroplasty surgeon and a year six trainee) made a forced choice decision of whether they would perform a TKR or UKR based on the same pre-operative radiographic and clinical data in 140 individual patients. Consistency of decision was also evaluated for each surgeon 3 months later and the effect of additional clinical data was also evaluated. The sample consisted of the 100 patients who had subsequently undergone UKR and 40 who had undergone TKR.Purpose
Method
To evaluate the results of Elastic Stable Intramedullary Nailing (ESIN) for displaced, unstable paediatric forearm diaphyseal fractures. A retrospective, consecutive series study of 60 patients treated with ESIN between February 1996 and July 2005.Aims
Method
The surgical correction of hammertoe deformity of the lesser toes is one of the most commonly performed forefoot procedures. In general, percutaneous Kirschner wires are used to provide fixation to the resected proximal interphalangeal joint. Although these wires are effective, issues such as pin tract infection as well as difficult postoperative management by patients make alternative fixation methods desirable. The biomechanical studies suggested that the bioabsorbable implant would be a suitable fixation device for the hammer toe procedure. These wire are made of a copolymer of 82% poly-L-lactic acid and 18% polyglycolic acid. The aim of our study was to assess the clinical outcome of these two implants. We compared 100 consecutive proximal interphalangeal joint fusions performed with each implant. There was no statistically significant difference in the fusion rate at six months using either implant. However, there was significant statistical difference in cost, rate of infection, implant migration, recurrence of deformity, patient’s return to driving, walking with routine foot wear and satisfaction. There was 11% rate of reactive inflammation in the absorbable wire group but no infection. The study shows the absorbable wires are safe for fusion of proximal inter phalangeal joints.
We aimed to audit the results of one stop fragility fracture risk assessment service at fracture clinic for non-hip fractures in 50–75 years old patients at Newcastle General Hospital. Currently, fewer than 30% of patients with fragility fractures benefit from secondary prevention in the form of comprehensive risk assessment and bone protection because of multifactorial reasons. We have a fragility fracture risk assessment service staffed by an Osteoporosis Specialist Nurse equipped with a DEXA scanner located at the fracture clinic itself. We carried out a retrospective audit of 349 patients of 50–75 years with suspected non-hip fractures referred from A&
E Department from October 2006 to September 2007. Patients over 75 years were excluded because as per NICE guidelines, they should receive bone protection without need of a DEXA scan. Out of these 349 patients with suspected fractures, 171 had fragility fractures. Median age was 64 years. 69 patients had humerus fracture, 65 had forearm fracture and 23 patients had ankle fracture and 14 had metatarsal fractures. Fracture risk assessment was carried out in 120 (70%) patients. Thirty Seven (31%) patients had osteoporosis and bone protection was recommended to GP. 38 (32%) had osteopenia and lifestyle advice was provided. 45 (37%) had normal axial bone densitometry. 90% patients had DEXA scan at the same time of fracture clinic appointment. Patients with male gender, undisplaced fracture and fewer fracture clinic appointments were more likely to miss fracture risk assessment. Our experience suggests that locating fragility fracture risk assessment service co-ordinated by an Osteoporosis Specialist Nurse at fracture clinic is an efficient way of providing secondary prevention for patients with fragility fractures. This can improve team communication, eliminate delay and improve patient compliance because of ‘One Stop Shop’ service at the time of fracture clinic appointment.
The kappa values for intra-observer agreement were from 0.34 to 0.69 (P<
0.001) for different observers. The observed agreement for these observers was from 70% to 94%. Only two most senior observers had good agreement.
The correct positioning of implant components in total knee replacement (TKR) is important for a successful long-term outcome. In order to address the problems inherent with conventional alignment methods, several computer-assisted navigation systems (CAS) have been developed. Despite numerous reports of clinical outcomes and system reliability, there is a lack of studies independently evaluating the precision and accuracy of such systems. We report on the design and development of a method and device to evaluate the accuracy of such a computer-assisted navigation system in two situations; 1) Normal or near-normal lower limb mechanical axis, and 2)Simulated femoral and/or tibial extra-articular deformity in either varus/valgus (x), internal/external rotation (y) or flexion/extension (z) planes. The system assessed was the Ci Knee-CAS navigation system (BrainLab/De Puy). This image-free system requires the registration of specific anatomical points to identify the mechanical axis of the lower limb and therefore provide information on resection level and alignment. In order to precisely measure and accurately reproduce these points we constructed a phantom device along anatomical guidelines, with lockable joints located at the mid-shaft of both femur and tibia. We then identified geometric CAS data; 1) Tibial resection height, and 2) Tibial resection plane, and using specially written software compared this against validated co-ordinate measurements independently obtained by a FaroArm co-ordinate measurement system (FARO Technologies, USA). This enabled data from the navigation system to be directly compared against highly accurate reference measurements. Accuracy of the system was then assessed with both normal mechanical alignment of the lower limbs and simulated extra-articular deformity.
To determine the effect of experience of the operator and the effect of type of anaesthesia used on re-manipulation rates of fracture distal radius manipulated in A&
E, a retrospective review of distal radius fractures manipulated in A&
E between January 2000 and January 2001. Operators were divided into two categories: junior (SHO grade) and senior (higher grade) doctor. 54 patients with fracture distal radius had manipulation in A&
E. 15 male and 39 female patients with mean age of 61 years (52 for males and 63 for females) were included. 42 (78%) fractures were manipulated under haematoma block (18 by junior, 23 by senior doctor) and 12 (22%) fractures were manipulated under Bier block (1 by junior, 11 by senior doctor). Operator’s grade was not clearly mentioned in one case. 13 out of 54 patients (24%) needed fracture re-manipulation under general anaesthesia. 12 out of 42 fractures manipulated under haematoma block (30%) needed re-manipulation compared to only one out of 12 fractures (8%) manipulated under Bier block (p=0.25). 9 out of 19 fractures manipulated by junior doctors needed re-manipulation compared to only 4 out of 34 fractures manipulated by senior doctors (p=0.007). Haematoma block was used for 18 out of 19 cases by junior doctors and for 23 out of 34 cases by senior doctors (p=0.038). Average number of fracture clinic follow-ups was 4 (range 2 to 8). Junior doctors had significantly higher preference for haematoma block and significantly higher re-manipulation rate. Re-manipulation rates were higher with fractures manipulated under haematoma block compared to Bier block. Adequate training and supervision should be provided for SHOs while performing such procedures in A&
E. Use of Bier block as a regional anaesthesia for manipulation of distal radius fractures in A&
E should be encouraged.
The Phantom based Computer assisted orthopaedic surgical system (CAOSS) has been developed collaboratively by the University of Hull and the Hull Royal Infirmary, to assist in operations like dynamic hip screw fixation. Here we present summary of our system. CAOSS comprises a personal computer based computer system, a frame grabber with video feed from a C-arm image intensifier, an optical tracking system and a radiolucent registration phantom which consists of an H arrangement of 21 metal balls. The phantom is held in position by the optically tracked end-effector. Knowing the optical position of the phantom, a registration algorithm calculates the position of C-arm in coordinate space of the optical tracking system. Computer based planning uses an anteroposterior (AP) and lateral image of the fracture. Marks are placed on the 2D projections of femoral shaft, neck and head on the computer screen, which are then used to create 3D surgical plan. The computer then plans a trajectory for the guide wire of DHS. The depth of the drill hole is also calculated. The trajectory is then shown on both AP and lateral images on the screen. CAOSS meets all the requisite of electrical and electromagnetic radiation standards for medical equipment. There has been extensive validation using software simulation, performance evaluation of system components, extensive laboratory trials on plastic bones. The positional accuracy was shown to be within 0.7mm and angular accuracy to be within 0.2°. The system was also validated using Coordinate Measurement Machine. Our system has the unique feature of the registration phantom which provides accurate registration of the fluoroscopic image.
Our aim was to assess the reproducibility and the reliability of the Weber classification system for fractures of the ankle based on anteroposterior and lateral radiographs. Five observers with varying clinical experience reviewed 50 sets of blinded radiographs. The same observers reviewed the same radiographs again after an interval of four weeks. Inter- and intra-observer agreement was assessed based on the proportion of agreement and the values of the kappa coefficient. For inter-observer agreement, the mean kappa value was 0.61 (0.59 to 0.63) and the proportion of agreement was 78% (76% to 79%) and for intra-observer agreement the mean kappa value was 0.74 (0.39 to 0.86) with an 85% (60% to 93%) observed agreement. These results show that the Weber classification of fractures of the ankle based on two radiological views has substantial inter-observer reliability and intra-observer reproducibility.
