The purpose of this paper was to investigate the predictability of outcome of a consecutive series of cemented unicompartmental or total knee replacements in a single surgeon series.

Between September 2006 and February 2009, ninety-nine cemented, fixed bearing TKR were performed with patellar resurfacing. 52 cemented Miller Galante (Zimmer) Tibio-femoral UKR were performed in the same time interval. The minimum follow up was 6 months. Oxford and AKSS knee scores were collected prospectively at pre-operative and at routine follow up appointments.

Pre-operative mean AKSS Knee score for TKR group was 33.9 and improved to 84.2 at 1 year. Mean scores for Tibiofemoral UKR were 40.4 improving to 84.3 at 1 year.

Pre-operative mean Oxford knee score for TKR group was 34.6 (28%) and improved to 16.6 (65%) at 1 year. Mean scores for UKR were 28.5 (41%) improving to 14.0 (71%) at 1 year. These data would suggest that unicompartmental replacement performs as well as TKR.

However, in the TKR group, 59% achieved a knee score >85 and 23% an Oxford score >80%. In the UKR group, 67% achieved knee score >85 and 45% an Oxford score >80%. Conversely, only 5% of TKR achieved knee score <50 and 20% Oxford score <50% whilst 10% of UKR had a knee score <50 and 26% and Oxford score <50%.

These data show that whilst mean outcomes for TKR and UKR look similar, TKR offers a more predictable outcome with fewer clinical failures but also fewer excellent results. UKR offers a more polarised set of outcomes with far more clinically excellent results but also more clinical failures. These data can inform the ongoing debate regarding the role of unicompartmental arthroplasty. Patient selection is clearly critical but remains an inexact process.

Unicompartmental knee arthroplasty remains controversial in some quarters and has been subject to recent negative press. The aim of the present study was to determine the differences in pre-operative status and early post-operative improvement between patients having unicompartmental knee Replacement (UKR) and Total Knee Replacement (TKR).

Methods: A Prospective study. Ethical approval was obtained prior to the study. Patients undergoing knee arthroplasty by two orthopaedic surgeons were included. Decision to proceed to unicompartmental or total knee replacement was at the surgeons’ discretion and was not randomised. The Oxford and the Ameri-can Knee Society scores were used to assess outcome. (Oxford score was used as a 0–48 scale; 0 being better and 48 worse). Scores were documented pre-operatively and at six weeks post-operatively.

Results: 104 patients were included in the study. 84 patients had TKR and 20 patients had UKR. Patients under going TKR had significantly worse Oxford, knee and function scores pre-operatively (32.2, 29.2 and 39.6) as compared with the UKR patients (28.5, 40.5 and 46.7) (P= 0.03, 0.001 and 0.026 respectively). TKR was associated with greater improvements in Oxford (P= 0.025), knee (P=0.0.027) and function (p=0.06) scores. However, the post operative scores were comparable; 20.4, 78.9 and 58.7 for TKR and 20.7, 80.9 and 57.9 for UKR.

Conclusions: It could perhaps be expected that patients with unicompartmental disease would have better pre-operative knee status than patients with more advanced multicompartmental disease. It is therefore understandable that patients receiving total knee replacements are able to improve more post-operatively than those receiving unicompartmental devices. Unicompartmental knees achieve only marginal initial superiority in terms of knee scores at 6 weeks follow-up. This is important and if clinical superiority and prosthesis longevity are not proven at longer term follow-up it would question the use of unicompartmental arthroplasty.

The aim of this study was to document the thickness of the patellofemoral joint before and after unicompart-mental joint replacement and to correlate these data with knee outcome scores.

Seventeen patients (22 knees) who underwent Patello-femoral replacement with FPV (Wright Medical) prosthesis between 2006 and 2008 were identified retrospectively and analyzed using chart and radiological review. Oxford and AKSS knee scores were gathered prospectively pre-operative and at follow-up.

Trochlear height was measured using lateral radiograph of the knee by measuring the distance between anterior distal femoral cortex and the highest point of trochlea. Trochlear height was compared pre and postoperatively. The range of movement and the Oxford and American knee society knee scores at six weeks postoperatively were noted. Association between increased trochlear height and improved range of motion was studied.

All but two patients regained full knee extension. Postoperative mean range of flexion of the knee joint was 114 degrees. The mean Oxford knee score at 6 weeks postoperatively was 21 points. The mean American Knee Society Knee Score was 85 points and function score 60 points.

We found the average trochlear height to be 6.2 mms pre and 9.7 mms post operatively with an average increase of 3.5 mms. We found no relationship between range of motion of the knee and knee function and trochlear height. This is important because there has been concern that ‘overstuffing’ of the patellofemoral joint can lead to stiffness and failure of resolution of pain post-operatively. Rather it appears that the FPV prosthesis restores the previous anatomical thickness of this compartment.

We conclude that FPV Patello-femoral replacement results in correct anatomical reconstruction of the trochlear height. This should in turn result in durable improvements in pain and function

Aims: To establish whether pre-existing anxiety and depression negatively impacts symptomatic and functional outcome of knee arthroplasty.

Methodology: A prospective study. Ethical approval was obtained prior to the study. Psychological status was assessed using the Hospital Anxiety and Depression Scale; a validated self-assessment tool for detecting anxiety and depression. The Oxford and the American Knee society scores were used to assess the knee status. All scores were documented pre-operatively and at six weeks post-operatively. Results were submitted for independent statistical analysis.

Results: 105 consecutive primary knee replacements were included in the study. 39% (41 patients) had abnormal pre-operative anxiety states. This percentage dropped to 28.2% (29 patients) post-operatively (P=0.034). 25.7% (27 patients) had abnormal pre-operative depression states which improved to 15.5% (16 patients) post-operatively (P=0.011). There were high degrees of correlation between abnormal anxiety and depression states both pre-operatively (P< 0.001) and post-operatively (P< 0.001). Patients with abnormal anxiety pre-operatively had worse knee scores both pre-operatively (P=0.17) and post-operatively (P=0.009) than those who did not. Patients with abnormal depression pre-operatively had worse pre-operative Oxford scores (P=0.036), and worse Oxford (p=0.006) and AKSS knee scores post-operatively (0.043).

Conclusions: Abnormal anxiety and depression states are common in patients with knee arthritis presenting for knee arthroplasty. These conditions can improve post-operatively. Patients with abnormal pre-operative anxiety and depression do less well following knee arthroplasty than those who do not. Pre-operative psychological assessment is easy to perform and does act as a predictor of early outcome. Further research is needed to assess whether treating these psychological conditions prior to knee arthroplasty improves the outcome or not.

The Profix knee replacement arthroplasty manufactured by Smith and Nephew has been in use for the past five years however there are few published outcome data for this prosthesis.

The purpose of this study was to provide clinical outcome data for a cohort of patients with a Profix TKR at a minimum 3 years follow up.

There were 65 joint replacements in 58 patients all performed by or under the direct supervision of one of two senior consultant Orthopaedic surgeons. There were 34 right and 31 left knees replaced in 31 male and 27 female patients. Mean age of the patients was 69 years (51–84 years) and mean body mass 89Kg (45–140Kg).

The femoral component was uncemented in 49 knees and cemented in 16 knees. The tibial component was cemented in all 65 cases. There were 53 mobile bearing polyethylene inserts and 12 fixed bearing knees. The patella was resurfaced primarily in 32 cases.

Using the Oxford Knee score, the mean knee score was 20.7 (Range 12–42) where a perfect score is 12 and the worst possible score 60. Mean clinical range of movement was 111 degrees (Range 90–130 degrees).

Of the 65 joints, 13 have required or are awaiting some form of re-operation. These included 3 for patellae that were not resurfaced at the index arthroplasty, 6 for secondary insertion or revision of mobile bearing locking-screws and one femoral revision for failure of on-growth of an uncemented femoral component.

The finding of loosening of the mobile bearing locking screw in three well functioning knees highlights the importance of Xray follow-up of patients even if their knee scores are entirely satisfactory.

Overall, the clinical results of this prosthesis are satisfactory, however these data would support routine patellar resurfacing and use of the cemented fixed bearing option for the Profix arthroplasty.

The purpose of this study was to determine the incidence of revision total knee replacement (TKR) within 5 years of the index procedure at a large multi-surgeon unit using a single prosthesis and to determine the cause of failure of those implants.

This was a retrospective review of all primary Kine-max Plus TKR performed at the Avon Orthopaedic Center between 1.1.1990 and 1.1.2000. Cases were identified that required revision arthroplasty in any form within 5 years of the index procedure. Case notes and Xrays were reviewed to determine causes of failure.

There were 2826 primary Kinemax Plus TKR performed during the study period. Of these 20 were known to have required revision surgery within 5 years. 8 were revised for deep infection of the prosthesis and 12 for aseptic causes. The overall incidence of premature failure of the Kinemax Plus TKR at 5 years was 0.71%. The incidence of aseptic premature failure at 5 years was 0.42%. Detailed examination of the clinical records indicated that some form of technical error at the time of the index arthroplasty was responsible for the early failure of 6 prostheses. This equates to 0.21% of the procedures performed. Aseptic loosening of the remaining 6 cases could not be attributed to a specific cause.

Previous research has shown an increase in chromosomal aberrations in patients with worn implants. The type of aberration depended on the type of metal alloy in the prosthesis. We have investigated the metal-specific difference in the level of DNA damage (DNA stand breaks and alkali labile sites) induced by culturing human fibroblasts in synovial fluid retrieved at revision arthroplasty.

All six samples from revision cobalt-chromium metal-on-metal and four of six samples from cobalt-chromium metal-on-polyethylene prostheses caused DNA damage. By contrast, none of six samples from revision stainless-steel metal-on-polyethylene prostheses caused significant damage. Samples of cobalt-chromium alloy left to corrode in phosphate-buffered saline also caused DNA damage and this depended on a synergistic effect between the cobalt and chromium ions.

Our results further emphasise that epidemiological studies of orthopaedic implants should take account of the type of metal alloy used.

Aims: To study the levels of genetic damage caused to a cultured human cell line when cultured with synovial ßuid retrieved from revision arthroplasty joints. Methods: Synovial ßuids were retrieved from revision hip and knee arthroplasty patients with bearings made from Cobalt chrome-on-Cobalt chrome, Cobalt chrome-on-polyethylene, Stainless Steel-on-polyethylene and Titanium-onpolyethylene. Control synovial ßuid was retrieved from primary arthroplasty cases. Synovial ßuid was cultured with human primary þbroblasts for 48 hours in a cell culture system under standardised conditions. The ÔCometñ assay was used with an image analysis system to measure levels of DNA damage caused by the various synovial ßu id samples. Results: Synovial ßuids from Cobalt Chrome-on-Cobalt Chrome and Cobalt Chrome-on-polyethylene joint replacements caused signiþcantly (p< 0.05) more genetic damage than synovial ßuids from Stainless Steel-on-polyethylene and Titanium-on-polyethylene cases. Control synovial ßuid caused minimal change. Conclusions: Different alloys used in Orthopaedic implants are associated with different levels of DNA damage to human cells in vitro. We have no evidence for any long-term health risk to patients with such implants. Further research is needed in this þeld.

Anterior knee pain due to dysplasia of the extensor mechanism is common. We have studied 137 knees (103 patients) in order to identify a rapid and reproducible radiological feature which would indicate the need for further analysis.

Overall, 67 knees (49%) had at least one radiological abnormality; 70 (51%) were considered normal. There were five cases of Dejour type-3 dysplasia of the femoral trochlea, nine of type-2 and 12 of type-1. There were 49 cases of patella alta and five of patella infera. Four knees had an abnormal lateral patellofemoral angle (patellar tilt), and in 15 knees there was more than one abnormality. Classification of trochlear dysplasia was difficult and showed poor reproducibility. This was also true for the measurement of the lateral patellofemoral angle. Patellar height was more easily measured but took time. The sulcus angle is an easily and rapidly measurable feature which was reproducible and was closely related to other features of dysplasia of the extensor mechanism.

The finding of a normal sulcus angle suggested that seeking other radiological evidence of malalignment of the extensor mechanism was unlikely to reveal additional useful information. The severity of other features of dysplasia of the extensor mechanism correlated with increasing sulcus angle.

We took posteroanterior weight-bearing radiographs, both with the joint fully extended and in 30° of flexion, in a consecutive series of 50 knees in 37 patients referred for the primary assessment of pain and/or stiffness. These radiographs were reported ‘blind’ both by an orthopaedic surgeon and a radiologist. Direct measurement of the joint space, together with grading of the severity of erosion according to the Ahlback criteria, was undertaken. Any other abnormality present was also documented.

The radiographs of the knees in 30° of flexion consistently showed more advanced erosion in both the medial (p = 0.001) and the lateral (p = 0.0001) tibiofemoral compartments, when compared with those of knees in full extension. The Ahlback classification of 25 joints was altered, in some cases by several grades, by the flexed position of the joint. In every case in which another abnormality was identified on the radiograph in full extension, it was also noted on that of the knee in 30° of flexion. In a further four cases, additional pathology could only be seen in the flexed knee. Every patient was able to complete the radiological examination without difficulty. Our study supports the adoption of a weight-bearing view in 30° of flexion as the standard posteroanterior radiograph for the assessment of tibiofemoral osteoarthritis in patients over 50 years of age.