Abstract

Background

Defining optimal coronal alignment in Total Knee Replacement (TKR) is a controversial and poorly understood subject. Tibial bone density may affect implant stability and functional outcomes following TKR. Our aim was to compare the bone density profile at the implant-tibia interface following TKR in mechanical versus kinematic alignment.

Tibial bone density may affect implant stability and functional outcomes following total knee replacement (TKR). Our aim was to characterise the bone density profile at the implant-tibia interface following TKR in mechanical versus kinematic alignment. Pre-operative computed tomography scans for 10 patients were obtained. Using surgical planning software, tibial cuts were made for TKR either neutral (mechanical) or 3 degrees varus (kinematic) alignment. Signal intensity, in Hounsfield Units (HU), was measured at 25,600 points throughout an axial slice at the implant-tibia interface and density profiles compared along defined radial axes from the centre of the tibia towards the cortices. From the tibial centre towards the lateral cortex, trabecular bone density for kinematic and mechanical TKR are similar in the inner 50% but differ significantly beyond this (p= 0.012). There were two distinct density peaks, with peak trabecular bone density being higher in kinematic TKR (p<0.001) and peak cortical bone density being higher in mechanical TKR (p<0.01). The difference in peak cortical to peak trabecular signal was 43 HU and 185 HU respectively (p<0.001). On the medial side there was no significant difference in density profile and a linear increase from centre to cortex. In the lateral proximal tibia, peak cortical and peak trabecular bone densities differ between kinematic TKR and mechanical TKR. Laterally, mechanical TKR may be more dependent upon cortical bone for support compared to kinematic TKR, where trabecular bone density is higher. This may have implications for surgical planning and implant design.

Introduction

Patellar resurfacing affects patellofemoral (PF) kinematics, contact mechanics, and loading on the patellar bone. Patients with total knee arthroplasty (TKA) often exhibit adaptations in movement patterns that may be linked to quadriceps deficiency and the mechanics of the reconstructed knee [1]. Previous comparisons of PF kinematics between dome and anatomic resurfacing have revealed differences in patellar sagittal plane flexion [2], but further investigation of PF joint mechanics is required to understand how these differences influence performance. The purpose of this study was to compare PF mechanics between medialized dome and medialized anatomic implants using subject-specific computational models.

Introduction

Accurate measurement of knee motion is necessary for assessment of natural joint function and in the diagnosis of pathology. In particular, precise knowledge of natural knee mechanics provides useful metrics for comparison to knee function following total knee arthroplasty (TKA). Reported measurements of natural knee kinematics during activities of daily living are rare, and often do not include both tibiofemoral (TF) and patellofemoral (PF) articulations. What's more, most studies record knee motion of younger subjects that are not necessarily representative of the age range associated with degenerative changes and TKA. The purpose of this study was to measure TF and PF kinematics of healthy older adults as they performed activities of daily living, including tasks considered more demanding for the knee [1].

Objectives

Modularity in total knee arthroplasty, particularly in revisions, is a common method to fit the implants to a patient's anatomy when additional stability or fixation is needed. In such cases, it may be necessary to employ multiple points of modularity to better match the anatomy. Taper junction strength at each of these levels is critical to maintain the mechanical stability of the implant and minimize micromotion. This effect of distributed assembly loads through multiple tapers and the resulting strength of the construct have not been previously evaluated on this revision tibial implant. The purpose of this study was to evaluate the possible dissipation of impaction force through multiple taper connections as compared to a single connection.

Aims

We review our experience of Coonrad-Morrey total elbow arthroplasty (TEA) for fractures of the distal humerus in non-rheumatoid patients with a minimum of ten years follow-up.

We present a series of 23 total ankle replacements revised for balloon osteolysis and aseptic loosening with a hind-foot fusion nail without the use of bone graft. This is the largest series of total ankle replacements revised to a hindfoot fusion with a nail presented in the literature.

Initial assessment involved investigations to rule out infection and a CT scan of the ankle to assess the size of cysts. Patients underwent surgery in a single stage procedure. The surgery involved excision of the fibula and preparation of the sub-talar joint through a lateral incision; removal of the implant and preparation of the talar and tibial surface with flat cuts through an anterior incision and safe excision of the medial malleolus aided by a medial incision. The prepared surfaces were then compressed and fixed using a Biomet Phoenix Nail. Patients were then followed up to assess for clinical and radiographic union.

This study involved 18 male and 4 female patients with an average age of 67. All patients had AES ankle replacements (Biomet) in-situ, undergoing revision surgery for aseptic loosening with balloon osteolysis. At a mean follow up of 13.9 months, 96% (22/23) of ankles achieved osseous union across the tibio-talar joint with 1 patient achieving a partial union. 91% (21/23) of patients achieved union across the subtalar joint with 2 patients identified as having a non-union.

1 patient with a subtalar non-union suffered a broken nail and required revision surgery. The only other identifiable complication was a single patient sustained a stress fracture at the proximal tip of the nail, which was treated conservatively.

We believe this method is a reliable and reproducible method of achieving osseous union following a failed total ankle replacement without using graft. Although patients may have a leg length discrepancy, none have requested leg lengthening.

Distal clavicle fractures have a significant non-union rate, and are often managed operatively. Many of the fixation devices used have a high complication rate or require removal. An arthroscopic technique using the Tightrope device (Arthrex) has been used in our institution. We aimed to describe our initial results.

Eighteen cases were identified retrospectively, and the notes and radiographs reviewed. Twelve patients were male, six female, with mean age 33 years. All fractures were displaced, lateral to the coraco-clavicular ligament complex: six showed marked comminution. Mean follow-up was thirteen weeks. Fifteen fractures united, with a mean radiological time to union of 8 weeks (range 6-13 weeks). There were three surgical complications. In one, the clavicular button was not seated correctly on bone, and early failure required revision surgery. In another, there was inadequate reduction, radiographic non-union at five months and subsequent device failure. In the last, there was radiographic non-union, but the patient was asymptomatic.

The arthroscopic tightrope device provides minimally invasive stabilisation and reliable union. The complications seen were related to incorrect technique, and anticipate the complication rate to diminish as the technique is developed. We recommend the use of this technique for the stabilisation of distal clavicle fractures.

Total elbow arthroplasty (TEA) has been shown to be a treatment option for elderly patients with complex distal humeral fractures and osteoporotic bone. The published results have often included rheumatoid patients who traditionally would be expected to do well from elbow arthroplasty. Only short-term results have been published using this technique in non-rheumatoid patients.

The current study contains the largest number and longest follow-up of non-rheumatoid patients whose fractures have been treated with a non-custom TEA. In total there were 26 patients, mean age 72 years, 22 female and 4 male, 25% dominant arm. The mean follow-up was of 5 years. There was 1 case of loosening, 1 radial nerve palsy and 2 cases of heterotrophic ossification. At final review the mean range of flexion/extension was 97.5 degrees and the mean range of pronation/supination was 151.75 degrees. The mean Mayo Elbow Performance score was 92.

We would suggest that TEA provides a very satisfactory outcome in elderly patients with complex distal humeral fractures, the benefit of which can be observed at a mean of 5 years.

Background: Intra-articular distal humeral fractures in the elderly are difficult to treat. There is evidence in the literature to support the use of both open reduction and internal fixation (ORIF) and total elbow arthroplasty (TEA) as primary procedures, although we have been unable to find any direct comparisons of outcome.

Methods: This study reports the results of ORIF in 12 elderly patients with distal humeral fractures and compares the outcome with 12 matched patients who had undergone TEA. All procedures were performed by two Consultant elbow surgeons. The Coonrad-Morrey TEA was used in all cases of TEA and a double-plating technique was used in all ORIFs. Both groups of patients were similar with respect to fracture configuration, age, sex, comorbidity and hand dominance. The mean follow-up in both groups of patients was over 30 months.

Results: At final review, patients who had had a TEA had a mean Mayo score of 91 and a range of flexion/extension of 90 degrees. There was 1 superficial wound infection that resolved with antibiotics, 1 temporary radial nerve palsy, and 1 case of heterotrophic ossification The ORIF group had a mean Mayo score of 89 (p> 0.05) and a range of flexion/extension of 112 degrees (P=0.03). There was 1 case of heterotrophic ossification, 2 cases of ulnar nerve compression that needed decompression and 1 superficial wound infection that resolved with antibiotics. All the fractures united.

Conclusion: This study indicates that both treatment modalities can lead to excellent results. ORIF has the advantage of preserving the joint and once union has occurred has a low risk of long term complications.

A prospective study on the management of 23 patients with complex high energy tibial fractures was carried out to assess the outcome following the use of different external fixators. They were all followed up clinically and radio logically till fracture union.

The average age 42 years (range 13–77 years) 17 male & 6 females. Fourteen were closed and 9 open. Eight were falls from height, 9 RTAs, one crush injury and one assault. All of the open fractures were grade 3. Six patients had proximal tibial fractures (one Schatzker Type-II, one Type-IV, two Type-V and two Type-VI) They united at an average of 20 weeks (range 10–40 weeks). Seven were Shaft fractures average duration to union 30 weeks (range 8–104 weeks), and eight were Pilon fractures (Two Ruedi & Allgower Type-II & Six Type-III) they united at an average duration of 13 weeks (range 7–20 weeks)

All patients achieved clinical and radiological union at a mean duration of 22 weeks. Sheffield Ring fixator [SRF] was used primarily in 11 patients, none failed. Two had initial monolateral fixators which were converted to SRF. Two were managed with Illizarov frames and three with hybrid fixators. Seven patients had an initial monolateral fixator, two failed and were converted to a Sheffield fixator, 2 planned conversion to an intramedullary nail, one developed a delayed union and was converted to a Sheffield fixator, only two continued till union. Nine patients developed pin tract infection needing Antibiotics, three of them developed Osteomyelitis, Four had failure of fixation needing a second operation.

Two developed malunion, one managed with total knee replacement, another required Ankle fusion. The average SF 12 score for the Sheffield group PCS was 52.1 and MCS of 51.7. For the Monolateral fixator group PCS was 47.2 and MCS of 48.1. For the Hybrid fixator group PCS of 34.7 and MCS of 42.7 and for the Ilizarov group PCS was 39.85 and MCS was 55.05.

In this cohort of complicated High energy Tibial fractures, those managed with Circular Frames especially SCF augmented with interfragmantary screws proved to be most successful with a very lower failure rate and better patient satisfaction.

Introduction: We prospectively followed all hip fracture patients admitted between 2004–2006, identified cases where the intention was to treat conservatively and compared their functional outcome and mortality with a similar cohort treated surgically over the same period.

Methods: We recorded length of hospital stay, place of discharge, pre and post-fracture mobility and residence, 30 day and 1 yr mortality, re-admission and delayed surgery. The group treated surgically was recruited and matched for age, gender, pre and post fracture mobility, mental confusion and independence with the conservatively treated group.

Results: 25 patients were treated conservatively. 22 patients treated surgically over the same period were recruited. The mean hospital stay was 13 days in both groups. There were 4 extracapsular (3 displaced) and 21 intracapsular fractures (5 displaced) in the conservative arm and 11 extracapsular and 9 intracapsular fractures in the surgically treated arm. 4 patients from the conservative treatment group underwent late surgery 20 days – 2 months after the index event. Surgically treated group had 11 dynamic screw fixation, 1 cannulated screw, 1 total hip replacement and 7 hemiarthroplasty. 9/14 of the conservatively treated patients were mobile independently or with aid after treatment compared to 11/16 patients after surgery. 7/16 patients treated conservatively were living independently in their own residence, compared to 10/14 patients in the operatively treated patients. 1 month and 1 year mortality in conservatively treated group was 4/21 and 7/21 respectively compared to 1/20 and 5/20 in the operative fixation group. There was no statistically significant difference in mobility, residence or mortality between the two groups (Fisher exact test, p > 0.05).

Discussion: Conservative management after hip fracture in medically unfit patients does not result in statistically significant difference in functional outcome or mortality compared to patients treated surgically.

Introduction: Distal radius metaphyseal fractures in children are not uncommon, but when they occur proximal to the insertion of the pronator quadratus muscle, reduction and maintenance of reduction can be challenging. The deforming forces at the fracture site result in pronation and shortening of the distal fragment. Manual manipulation of this fracture often results in tearing of the dorsal periosteum and hence renders this fracture highly unstable.

Aim: We present a novel easily reproducible mini-open surgical technique and functionally and radiologically evaluate a series of eleven patients who have undergone this technique.

Materials and Methods: The surgical technique consists of a mini-open intrafocal image intensifier guided reduction technique with percutaneous k-wiring fixation. Five males and six females with an average age of 8.8 years (range 5 to 13 years), who sustained a pronator quadratus distal radius fracture and subsequently underwent this surgical technique from 2005 to 2007, were evaluated both radiologically in terms of radial length, radial tilt and volar tilt compared with the contralateral limb and functionally using the Mayo Modified wrist score and the patient related wrist evaluation questionnaire.

Results: Patients were followed up for an average of 18 months (range 2–31 months). All patients achieved clinical and radiological union. No patient required remanipulation for loss of reduction. Radiological outcome measures similar to contralateral limb with good functional scores. No complications were noted. All patients returned to preoperative level of function

Conclusion: This minimally invasive technique has been shown to be technically easy, reliable and reproducible with excellent results and low risk of displacement compared to other techniques used to treat this potentially challenging fracture.

Total elbow arthroplasty (TEA), as a primary procedure and open reduction and internal fixation (ORIF) have been used to treat complex intra-articular distal humeral fractures in elderly patients. The failure rate after ORIF is high and TEA has often been used as a salvage procedure. Although satisfactory results have been reported after TEA as a primary procedure, there are no publications reporting the results of TEA after failed internal fixation (FIF). In this study we compared the results of patients that had TEA after FIF with those that had had primary arthroplasty (PA). We reviewed the results of 9 consecutive patients who had FIF with 12 patients who had PA. All the operations were performed by one surgeon using the same technique and same prosthesis. Both groups of patients were similar with respect to ages, sex, co-morbidity and hand dominance. The mean follow-up for both groups of patients was 5 years. At final review, patients who had had FIF had a mean Mayo score of 68 and a range of flexion/extension of 90 degrees, there was 1 infection and 1 case of loosening. The PA group had a mean Mayo score of 88 and a range of flexion/extension of 96 degrees, there were no cases of infection or loosening. This study shows the results of TEA are satisfactory either as a PA or after FIF, however the results after PA are significantly better than after FIF.

Total elbow arthroplasty (TEA) has been shown to be a treatment option for elderly patients with complex distal humeral fractures and osteoporotic bone. The published results have often included rheumatoid patients who traditionally would be expected to do well from elbow arthroplasty. Only short-term results have been published using this technique in non-rheumatoid patients The current study contains the largest number and longest follow-up of non-rheumatoid patients whose fractures have been treated with a non-custom TEA. In total there were 26 patients, mean age 72 years, 22 female and 4 male, 25% dominant arm. All had a minimum of 5 years follow-up. There was 1 case of loosening, 1 radial nerve palsy and 2 cases of heterotrophic ossification. At final review the mean range of flexion/extension was 97.5 degrees and the mean range of pronation/supination was 151.75 degrees. The mean Mayo Elbow Performance score was 92. We would suggest that TEA provides a very satisfactory outcome in elderly patients with complex distal humeral fractures, the benefit of which can be observed for at least 5 years.

Distal biceps tendon ruptures are uncommon with a reported incidence of 1.24 per 100,000 per year.

They typically occur in males in the fourth decade.

Operative treatment has been shown to improve functional outcomes in the treatment of distal biceps tendon ruptures. A variety of surgical techniques have been described, usually using the dual incision Boyd-Anderson approach.

We report a series of 10 patients with 10 tendon ruptures treated using a single incision volar approach and using the Arthrex Biotenodesis screw to reattach the tendon to the radial tuberosity.

This method has been previously described in only one case report.

All ten patients underwent clinical assessment using the Mayo Elbow Performance Score (MEPS) and functional assessment using the DASH scoring system. The power was assessed isokinetically using the Nottingham Myometer.

Based on the MEPS and DASH grading system all patients achieved a good or excellent result.

In our experience reattachment of the distal biceps tendon using a single incision approach and Arthrex Biotenodesis screw is a new technique which gives a good functional outcome.

Background: The stability of fracture fixation is influenced by the type of fixation, densitometric and geometric structure of the bone. DXA measures the integral mass of trabecular and cortical bone mineral but cannot discriminate between the structurally and mechanically separate constitutes. Distribution and organisation of bone mass (the geometric structure) has the final determination of the mechanical properties of bone. Pq CT scan is able to measure densitometric and geometric parameters of bone structure. However, there are no reports in the literature on the relationship between these measurements and the strength of fracture fixation. Our aim is to study the correlation between geometric and densitometric measurements of Pq CT scan, with the strength of fixation of bicondylar tibial plateau fractures and to assess the role of both trabecular and cancellous bone in that strength.

Method: Eight Fresh frozen human cadaveric tibias were collected from subjects without a medical history of skeletal pathology. The proximal 10% of the tibia was scanned in a peripheral quantitative computer tomography scanner 1mm thick transverse slides, the cancellous and cortical bone mineral density of the proximal tibia were measured. The geometrical parameters: cortical area, trabecular area, bone strength index (BSI) and the Stress strain index (SSI) as non invasive indicators of the mechanical strength of the bone, were also calculated. A bicondylar tibial plateau fracture was simulated, stabilised, and then tested. All tibias were fixed with Dual buttress plating using a standard AO technique. Cyclic axial compression tests were performed. Inter-fragmentary shear displacements were measured using four extensometers. Failure was defined as over 3mm displacement.

Results: Except for the cortical density, there was a strong correlation between failure load and geometric and densitometric parameters. The trabecular density was the best predictor of fixation strength of tibial plateau fracture.

Discussion: Trabecular density is a more reliable parameter to measure than the cortical density. Therefore, the fixation strength of tibial plateau fracture is dominantly influenced by the mechanical properties of cancelous bone. Cortical bone has a secondary role.

These results highlight the importance of fixation techniques that rely on cancellous bone anchoring such as tensioned fine wire fixation in tibial plateau fractures.

Sixteen patients who underwent a revision operation for nonunion of fractures of the distal humerus following previous internal fixation were reviewed at a mean follow-up of 39 months (8 to 69).

The Mayo elbow performance score was excellent in 11, good in two, fair in two and poor in one. In 15 patients union was achieved and in one with an infected nonunion a subsequent bone graft was necessary in order to obtain union.

Age, gender, a history of smoking, mechanism of the injury and the AO classification of the initial fracture did not correlate with the development of nonunion. In 12 patients (75%), the initial fixation was assessed as being suboptimal. The primary surgery was regarded as adequate in only three patients. Our findings suggest that the most important determinant of nonunion of a distal humeral fracture after surgery is the adequacy of fixation.

This paper reports our experience of revision open reduction, internal fixation and bone grafting of distal humeral fracture non-unions and in addition looks specifically at factors that may predispose to the development of non-union.

Between 1993 and 2003 18 patients with distal humeral fracture non-unions underwent revision surgery with bone grafting and rigid internal fixation. Two patients were lost to follow-up leaving a study group of 16 patients.

The patients’ age, sex, mechanism of injury, AO classification of the initial fracture and the primary treatment method were analysed with respect to possible factors predisposing to non-union.

All revision procedures were performed by the senior author. The non-union site was debrided, bone grafted and rigidly internally fixed.

Clinical assessment was performed using the Mayo Elbow Performance Score and radiographs were reviewed for evidence of bony union.

The Mayo elbow performance scores were excellent in 11, good in 2, fair in 2 and poor in 1.

Our results indicate that age, sex and mechanism of injury are not important in the development of non-union. Twelve patients (75%) however were considered to have undergone inadequate management of the original fracture.

Our experience would suggest that to reduce the risk of non-union following distal humeral fractures appropriate consideration must be given to the established and well proven surgical techniques.

If adequate fixation is considered beyond the experience of the treating surgeon we would strongly advise referral to a specialist unit.