Between June 1986 and 1993, 208 Protek CLS total hip replacements were inserted in 174 patients. These have been reviewed clinically and radiologically by independent observers at 3 yearly intervals.

One hundred and sixty six hips in 137 patients were available for review 9 to 15.5 years from insertion (mean just over 10.5 years). There has been no significant clinical or radiological change when compared to reviews three and six years ago with regard to the Harris Hip Score and the pain and function components of this. There has also been no change in subsidence, heterotopic ossification or lucencies. There has been no significant difference in results between males or females, nor between other factors such as pre-operative diagnosis, the use of metal or ceramic heads, age at time of operation or length of follow up. The failure rate remains low, less than 4%, i.e. survival rate greater than 96%. The reasons for failure in general do not relate to the fixation of either the acetabular or femoral components.

The results of this long-term follow up of a large group of relatively young patients at time of insertion of arthroplasty remain very satisfactory.

Traditionally, immobilisation following achilles tendon rupture has been for 10 to 12 weeks.

We have previously published a series of 71 consecutive repairs with no re-ruptures, using a lateral surgical approach. The latter part of this cohort were immobilised for six weeks instead of 12, with early weight bearing. The lack of any re-ruptures encouraged us to pursue the accelerated rehabilitation.

This study documents a further 34 cases followed prospectively for 6–24 months (mean 15.9 months). All were repaired with a single Kessler-type suture using loop PDS, through a lateral approach. Patients were partial weight-bearing immediately in an Aircast boot with three cork heel wedges. At two-weekly intervals the wedges were reduced, and the boot abandoned after six weeks.

There have been no re-ruptures. Thirty of the 34 patients returned to pre-injury activity levels. All patients were satisfied or very satisfied with the immobilisation device and the accelerated rehabilitation regime. Cost savings were also made through use of a single removable orthosis rather than sequential casts.

We advocate this regimen of careful operative achilles tendon repair and accelerated weight bearing rehabilitation with a removable orthosis.

The purpose of the study was to review and present a series of early failures of the Miller Galante unicom-partmental knee replacement (UKR). Following several early failures all Miller Galante UKR’s inserted by the author (60 patients, 72 knees) were recalled for clinical and radiological review including assessment using the American Knee Society Score and the Oxford Knee Score. All knees with effusions were aspirated and specimens sent for histological analysis.

There were 22 females and 38 males with a mean age of 67 years. The mean follow up was 3.4 years. Six failures were noted with follow up from 10 months to 4 years. These 6 cases will be discussed in more detail including operative findings at revision and possible reasons for failure.

Early failure of this arthroplasty is unacceptable and caution should be exercised if contemplating using this implant unless more definite causative factors are identified.

Traditionally, immobilisation following Achilles tendon rupture has been for 10 to 12 weeks.

We have previously published a series of 71 consecutive repairs with no re-ruptures, using a lateral surgical approach. The latter part of this cohort were immobilised for six weeks instead of 12, with early weight bearing. The lack of any re-ruptures encouraged us to persue the accelerated rehabilitation.

This study documents a further 34 cases followed prospectively for 6–24 months (mean 15.9 months). All were repaired with a single Kessler-type suture using loop PDS, through a lateral approach. Patients were partial weight-bearing immediately in an Aircast boot with three cork heel wedges. At two-weekly intervals the wedges were reduced, and the boot abandoned after six weeks.

There have been no re-ruptures. Thirty of the 34 patients returned to pre-injury activity levels. All patients were satisfied or very satisfied with the immobilisation device and the accelerated rehabilitation regime. Costs savings were also made through use of a single removable orthosis rather than sequential casts.

We advocate this regimen of careful operative achilles tendon repair and accelerated weight bearing rehabilitation with a removable orthosis.

Isolated patello-femoral arthritis occurs in up to 10% of patients suffering osteoarthritis of the knee. Previous reports of several different patello-femoral designs have given indifferent results. The Lubinus prosthesis has a reported 50% failure rate at eight years in a study of 76 cases. The main reasons for failure were mal-alignment, wear, impingement and disease progression. The Avon patello-femoral arthroplasty was designed to solve some of these problems.

The first cases were implanted in September 1996 and entered into a prospective review. The outcome was assessed using pain scores, Bartlett’s patella score and the Oxford knee score. To date 207 knees have been treated and 95 knees have reviewed at two to five years. The median pain score improved from 15/40 points to 35 at five years. The movement increased from 114° to 120° at five years. The Bartlett patella score improved from 10/30 points to 26 at five years. The Oxford knee score improved from 19/48 points to 40 points at five years. Two patients developed mal-alignment (1%) one of which required distal soft tissue realignment. There have been no cases of deep infection, fracture, wear or loosening. Fifteen knees (7%) developed evidence of disease progression, twelve of which (6%) have required revision to a total knee replacement. The functional results are similar to those of a total knee replacement.

Results to date suggest that this improved design has all but eliminated the previous problems of mal-alignment and early wear. The functional results are as good as or better than those of a total knee replacement. There is a low complication rate and an excellent range of movement. Disease progression remains a potential problem. This type of prosthesis offers a reasonable alternative to total knee replacement in this small group of patients with isolated, early patello-femoral disease.

The aim of this study was to examine causes of the failed knee arthroplasty.

Since 1980 the Bristol Knee Replacement Registry has prospectively recorded data on 3024 patients. Complete original and 5 year follow up data was available on 999 knees.

The surgery was judged a failure if there was no improvement in the American Knee Society score at 5 years or if there had been a revision within that time.

The prosthesis used was Kinematic in 471 knees, the Medial Unicompartmental Sled in 258 knees, the Kinemax Plus in 134 knees and a variety of other designs.

At 5 years, 79 (7. 9%) either showed no improvement in the American Knee Society score or had been revised. The failure rate was 7% for the Kinematic, 7% for the medial Sled and 5% for the Kinemax Plus. 20% of the less frequently used designs failed.

Five (0. 5%) knee replacements failed because of infection. 22 knees (2. 2%) had significant comorbidity that precluded a satisfactory functional outcome. For 7 knees (0. 7%), the patient exhibited patterns of abnormal illness behaviour that were thought to explain the poor outcome. A further 27 knees (2. 7%) failed because of technical errors either at the time of surgery (13 cases, 1. 3%), or in selecting a prosthesis which failed prematurely (14 cases 1. 4%). No cause for failure could be identified in 12 cases (1. 2%).

The high failure rate amongst infrequently used prosthesis emphasises the need to use established designs. No cause for failure could be identified in 12 cases and 5 were due to infection; such cases are hard to avoid. This study shows the importance of assessing both the overall physical and psychological state of the patient if disappointing results are to be avoided. The most frequent cause of an unsatisfactory outcome was a technical one, which should be avoidable.

Isolated patellofemoral arthritis occurs in up to 10% of patients suffering osteoarthritis of the knee. Previous reports of several different patellofemoral designs have given indifferent results. The Lubinus prosthesis has been shown to have a 50% failure rate at eight years in a study of 76 cases. The main reasons for failure were mal-alignment, wear, impingement and disease progression. As a result of these studies, a new prosthesis was designed to solve some of these problems.

The Avon patellofemoral arthroplasty was first implanted in September 1996. The cases have been entered into a prospective review with evaluations at eight months, two years and five years. The outcome was assessed using pain scores, Bartlett’s patella score and the Oxford knee score. To date, 186 knees have been treated; over 100 knees have been reviewed at two years and 20 knees at five years. The main pain score improved from a pre-operative level of 13.5 points out of 40 to 33.5 points at two years and 36 at five years. The mean pre-operative movement was 109° and this increased to 120° at five years. The Bartlett patella score improved from a pre-operative level of 10.5 points out of 30 pre-operatively to 23 points at two years and 25 at five years. The Oxford knee score was 20 points out of 48 pre-operatively and this improved to 35 points at two years and 40 points at five years. One patient developed subluxation, which required distal soft tissue realignment. No other patient has developed problems with alignment or wear. Ten knees have developed evidence of disease progression usually in the medial compartment of which six have required revision to a total knee replacement.

The results to date suggest that this improved design has all but eliminated the previous problems of malalignment and early wear. The functional results are as good or better than those of a total knee replacement. There is a low complication rate and an excellent range of movement. Disease progression remains a potential problem. This type of prosthesis offers a reasonable alternative to total knee replacement in this small group of patients with isolated, early patellofemoral disease.

The Bristol Knee Replacement Registry was established in the 1970’s and contains prospectively recorded data on 3024 patients. The present study examines the group of 812 patients for whom complete pre-operative and five year post-operative data is available in order to relate their eventual health status to the pre-operative demographic data and to disease severity. The group comprised 593 women and 219 men who had undergone either Kinematic, Total or Sled unicompartmental knee replacement.

Pre-operatively, the average American Knee Society Score (AKSS) was 89 with the elderly, rheumatoid patients and women having significantly lower scores.

Five years later the average AKSS had risen to 161 with patients of all ages, (including the over 80’s) gaining considerably. However, the rheumatoid patients remained more disabled as did women who had a final AKSS of 157 as opposed to 171 for the men (p< 0.01). In addition, a statistically significant finding was that those with the lowest pre-operative scores also had the lowest 5 year scores - they never catch up.

173 patients underwent bilateral knee replacement at separate times. Their pre-operative AKSS was significantly higher at the time of the second knee replacement (90) than the first (82) p< 0.01.

We conclude that since patients present earlier for their second TKR and those with most disability fail to catch up the procedure should be performed earlier in the natural history of the disease, especially in women.

The aim of this study was to report our experience of patellofemoral arthroplasty in isolated osteoarthrosis.

Material and Methods: The Lubinus Patellofemoral Arthroplasty was performed between 1989 and 1995 in 76 knees. The Avon Patella Femoral Arthroplasty was used from 1996 to 2001 in 187 knees. The average age of the patients was 65.5 years (range 36–87) with a male to female ratio of 1: 5. All the patients have been prospectively reviewed with standard radiographs, the Bristol Knee Score, and more recently Bartlett and Oxford scores.

Results: Patients with the Lubinus prosthesis were followed for an average of 7.4 years (range 5–10 years). Eleven patients (14 knees) have died and the remaining 62 knees have a 100% follow-up. The cumulative revision rate was 28% (21 out of 76). Survivorship at 8 years was 65% (Cl 49 to 77) for revision and 48% (Cl 36 to 59) for revision plus moderate pain. The two main complications were Maltracking 32% and progressive tibio-femoral arthritis in 9%.

The Avon Arthroplasty with improved design features for better tracking and congruity was introduced in 1996 and 187 have now been inserted in 147 patients. One hundred and nine knees have been followed for 8 months and 82 have completed the 2 year follow-up. Two patients have undergone revision to a TKR 97.5% (survivorship 2 out of 82). Three patients have had a unicompartmental arthroplasty added for disease progression. There have been no cases of patella maltracking or subliaxation.

Four year survivorship for moderate pain and revision is 96% (79 out of 82). Functional scores compared favourably with parallel series of total knee replacements.

Conclusion: The medium-term results of the Lubinus Patello Femoral Arthroplasty are unsatisfactory. We suggest the use of this prosthesis should be discontinued. The Avon Arthroplasty has improved results in the short-term.

The purpose of this study was to determine the rate of polyethylene wear in a fixed bearing knee replacement in order to establish a norm against which mobile bearing implants can be judged.

Method: Eighteen all polyethylene tibial components were retrieved when a St Georg Sled unicompartmental replacement was being revised. This prosthesis has a biconvex femoral component and a totally flat tibia; thus point loading occurs on at implantation. The implants had been in situ between 6 and 110 months, revision was predominantly for progression of the arthritic process.

Linear wear was measured using an electronic micrometer and volumetric wear by creating a mould of the defect using dental wax, and subsequently weighing the wax.

Results: All components developed dishing which varied in orientation but matched the alignment of the femoral component. A near congruous articulation was thus produced correctly aligned for that particular arthroplasty. The mean linear penetrative wear for the group was 0.33mm (0.09mm per year) and the volumetric wear 124mm³ (26mm³ per year). The rate of wear seemed greatest during the second year.

Conclusion: The wear rate for this totally non congruous implant was much less than anticipated. The linear penetrative wear is comparable to that reported for Charnley hip replacement though more than for a fully congruent mobile UKR. The volumetric wear is much lower than that thought to cause osteolysis. The surprisingly low wear rate suggests that the need for mobile bearing UKRs, with their greater technical demands, should be questioned.

The latest government targets state that by the end of 2005 the maximum waiting time for an outpatient appointment will be 3 months. These recommendations will not only increase the size of the outpatient clinics, but also the resources required thereafter. The purpose of this study was to analyse the outcome of new knee referrals to one consultant’s knee outpatient service in order to quantify the resources required to investigate and treat these patients.

All new patients attending one consultant’s knee out-patient service in the time period January 1st 1997 to December 31st 1997 were prospectively entered into a database recording patient details, source of referral and provisional diagnosis.

Eighteen months after the time period a cohort of 200 patients was randomly selected and the notes were analysed retrospectively. The number of outpatient appointment episodes (OPAs), MRI scans, physiotherapy referrals and surgical episodes generated were recorded for each patient.

Analysis of the initial database records show that a total of 662 new knee referrals were seen in 1997. 52% (341) were made up of the five most common diagnoses, these being osteoarthritis, anterior knee pain, major anterior cruciate ligament injury, medial ligament injury and medial meniscus injury.

Retrospective analysis of the 200 patient notes revealed that these patients required a total of 511 OPAs, 38 MRI scans, 178 courses of physiotherapy and 93 surgical episodes (53 elective and 40 daycase/emergency). These figures can be extrapolated to account for the total number of patients seen:

The resource implications of a new knee referral are substantial. Extra resources must accompany each new patient, otherwise, although government targets will be reached the time taken to complete each patient’s treatment will become longer. It is imperative that before an agreement is made to see new patients the resources required to manage them are in place.

A randomised, prospective trial comparing the percutaneous compression plate (PCCP) and the classic hip screw was performed for intertrochanteric fractures of the femur in 108 patients. The PCCP offers the ability to stabilise fractures with a minimal exposure and periosteal stripping thus preserving soft tissue cover.

Over a 19-month period all patients with extra-capsular fractures apart from subtrochanteric and pathologic fractures were included. They were classified as per Evans classification.

The patient’s pre-operative haemoglobin, premorbid mobility, medical and mental status were noted. The duration of the procedure, screening time, blood loss and any technical difficulty encountered along with the post-operative haemoglobin, drainage and transfusion requirements, as well as the length of stay in the orthopaedic unit and total length of stay in the hospital were recorded. Results were analysed using the Chi-square test and Student’s test.

The operating time was significantly longer in the PCCP group (mean 59vs49mins,P< 0.05). There was no significant difference between the two groups with regard to the other parameters measured.

There was no difference in the failure rate (2 cut-outs in the CHS group and one screw back-out in the PCCP.) With the device being of fixed single angled design it proved to be unsuitable for 3 patients.

The PCCP would appear to be as good as the more conventional device though it does not confer the perceived advantages of decreased duration of stay or significant reduction in transfusion requirement which are associated with other percutaneous procedures. The device is a single fixed angle one and is therefore not universally applicable to all patients.

The aim of this study was to investigate the hypothesis that unicompartmental knee replacement (UKR) of a single arthritic tibio femoral compartment can slow the progression of arthritis to the other compartment.

Method: Since 1974, a prospective database has been established in Bristol to register and follow up the results of unicompartmental knee replacement. Forty two prostheses that had survived for more than 10 years were examined using the Ahlbach radiological scoring system and compared to a control group of patients from the Bristol “OA 500” series, in which patients being treated conservatively for gonarthritis were regularly reviewed by clinical scoring and radiological analysis. The groups were sex matched.

All AP and lateral standing knee radiographs at entry and 8 years were scored using the Ahlbach scoring system. The Ahlbach system has been shown to have good inter and intra observer correlation, and to relate closely to pathological findings at operation. An intra and inter observer error study of our results confirmed good correlation.

Results: The groups were well matched but the OA 500 group showed a lower average age, though not a significant difference (62 years compared to 67 years). The lateral compartment of all knees in both groups were Ahlbach grade 0 or 1 group before operation or entry to the OA 500 register.

In the UKR group, four out of 42 knees showed progression of a single Ahlbach grade (9.5%). 2 revisions for arthritic progression were added to this group making a total of six out of 42 (14.3%). In the control group 12 of the 42 knees progressed by one or two Ahlbach grades and a further case underwent surgery making a total of 13 (31%). This difference was significant (p< 0.01).

Conclusion: Recent studies have shown that with a better understanding of design, improved selection of patients and better surgical technique, a UKR can have at least as good, if not better, results than a TKR at 5 year follow up, and has benefits of preservation of anatomy, earlier rehabilitation, preservation of bone stock and easier revision. Our radiological findings in this study will need to be correlated with further randomised prospective clinical studies, but suggest that progression of Osteoarthritis is reduced by UKR, and that this should be an additional stated benefit of this surgical technique.

Introduction: Traditionally adolescent anterior knee pain is considered to be a self limiting condition with no long term sequelae. However recently two publications have suggested the condition may be longer lasting. We wish to suggest that adolescent anterior knee pain may lead to patello femoral arthritis.

Method: We have carried out a comparative study assessing the incidence of previous adolescent anterior knee in patients who underwent patello femoral replacement for isolated patello femoral arthritis and have compared them with a matched group of patients who had medial unicompartmental replacement for isolated medial compartment arthritis without patello femoral disease.

All patients were sent a postal questionnaire enquiring about adolescent anterior knee pain, knee injury and patella instability.

Results: Ninety-three PFR patients and 86 UKR patients replied. The incidence of adolescent AKF and patella instability was higher in the PFR.group.

Conclusion: Adolescent anterior knee pain may not always be a benign self limiting condition since this as well as patella injury and instability was associated with subsequent isolated patello femoral arthritis.

The aim of this study was to analyse the kneeling ability of patients before and at one and two years after total (TKR), unicompartmental (UKR) and selective patellofemoral (PFR) knee arthroplasty, for osteoarthritis. Method: Data was prospectively collected on 253 knees, which underwent either TKR, UKR or PFR. A kneeling score was obtained by analysis of the relevant section of the Oxford Knee Score questionnaire. Scores were obtained pre-operatively and at 1 and 2 years post-operatively (minimum score 0, maximum 4). Absolute values and change following arthroplasty were recorded. Correlations with pain and other knee functions were also made.

Results: Kneeling ability prior to surgery was poor in all three groups (mean score 0.7 out of 4) and improved significantly after surgery (mean score at one year 1.13 and at two years 1.46 out of 4) (P< 0.001). Kneeling ability at 1 year differed significantly with operation type (p = 0.02). Kneeling ability improved most in the first year post-operatively but continued to improve between one and two years although the final function was still not good. Kneeling ability was best in UKR and worst in PFR, with the difference between these prostheses being statistically significant (P< 0.001).

Conclusion: Kneeling ability in osteoarthritic knees is poor but improves with arthroplasty. However, the majority of patients will still have difficulty kneeling.

The aim of this study was to demonstrate the effectiveness of a customised coupled arthrodesis nail.

Knee arthrodesis is now infrequently performed and is usually reserved as a salvage for infected Joint arthroplasty or occasionally for intractable pain. Many methods have been used. Recently locked intramedullary coupled nails have gained in popularity. To deal with all size combinations a large inventory is required. We wish to report our series using a customised implant and to compare the outcome with other methods of knee arthrodesis.

Nine patients underwent arthrodesis using this implant, six following infected arthroplasty, two for intractable anterior knee pain and following trauma. Comparison was made with 17 arthrodeses performed since 1993 using external fixation (8), plates (4), and long K-nails (5). Union was achieved in nine patients (100%) at a mean time of 10 months using the customised implant. There were no complications despite early weight-bearing. No further procedures were required. This contrasted with a union rate of 65% with a 76% complication rate using alternative techniques. Seventy six percent of this second group required a further operative procedure.

We conclude that a customised coupled intramedullary nail can give excellent stability allowing early weight-bearing, and results in a high union rate with minimal post-operative complications. The differences in need for further surgery and occurrence of complications were statistically significant (p< 0.001), and differences in in-patient stay and non-union rate were also significant (p< 0.05) using Fisher’s exact test.

In Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA) the total blood loss is composed of ‘visible’ blood loss from the surgical field and wound drainage, and blood loss into the tissues which is ‘hidden’. Blood management should be aimed at addressing the total blood loss.

56 TKAs and 46 THAs were prospectively studied. TKAs were performed with tourniquet. After tourniquet release, all drained blood was salvaged and significant volumes reinfused. No reinfusion was used for THAs.

The true total blood loss was calculated in the following way:

Patient Blood Volume (PBV) is: [1]

PBV = k1 x height3 + k2 x weight + k3

Therefore patient total Red Blood Cell volume (RBCv) is:

RBCv = PBV x Hct. (where Hct is Haematocrit)

Total RBCv loss = PBV x (Hct preop – Hct postop) + ml RBC transfused

The result is reconverted to Whole Blood volume.

Hidden Loss = Total Loss – Visible Loss.

In TKA, the mean total true blood loss was 1474ml. The mean hidden loss was 735ml. Therefore hidden loss is 50% of the total loss and the total true loss following TKA is twice the visible volume. In THA, the mean total true blood loss was 1629ml. The mean hidden loss was 343ml.

Thus hidden loss in THA is much smaller. (21%) Total loss is 1.3 times the visible loss. In the TKA group, comparing patients with large losses receiving reinfusion and those with small losses not receiving reinfusion, the proportion of total true loss which was hidden was the same, at 50%.

Patients with Body Mass Index (BMI) > 30 were compared with those with a BMI < 30 and no correlation was found between BMI and Hidden Loss.

Joint Replacement Surgery involves a ‘hidden’ blood loss which is not revealed and cannot be measured or reinfused in practice, but which should be taken into account when planning blood loss management. In TKA it is substantial. In THA it is much smaller and probably not of as much clinical concern. Hidden loss is no greater in the Obese patient.

Aim: To assess the functional results of revision TKR with the PFC/TC3 system, and to correlate this with the reasons for revision and restoration of joint height.

Method: One hundred and fifty three patients underwent revision TKR using the PFC/TC3 system. Data was prospectively collected (using the Bristol Knee Score) pre-operatively and at a mean of 4.2 years post-revision. Forty three revisions were for infection and 81 revisions were for aseptic loosening. Measurements of the joint height were made pre and post-operatively using Figgie’s method and were divided into three groups: lower by more than 5mm, restored and elevated more than 5mm. Use of distal augments and polyethylene thickness were recorded.

Results: The mean pre-op function score was 12 and post-operatively was 19 for the infection group and 20 for the aseptic loosening group. Revision after initial UKR gave a mean score of 21, while revision after TKR gave a mean score of 18 (max 27). Knees in which the joint line was elevated by more than 5 mm had a mean score of 17 while those where the joint line was restored had a mean score of 1 9. Recent increasing use of distal augments improved the joint line and results.

Conclusion: Revision using the PFC/TC3 system produced acceptable medium term functional results and good survival. Better restoration of joint line and functional results were achieved by distal femoral rather than proximal tibial augmentation.

Objective: To report the survivorship rate and clinical outcome of a large series of lateral unicompartmental replacements.

Method: 88 lateral St Georg Sled LTKRS were performed between 1978 and 1999. Clinical and radiological data was prospectively recorded at regular follow up and only 5 knees were lost during the 22 year period.

Results: 15 knees were revised after an average of 8 years. (eight for progressive arthritis, six for loosening and four for femoral fracture) 29 patients (30 knees) died during the course of the study. At final follow up (average 9 years) 50 of the 63 remaining knees were rated as good or excellent, nine as fair and nine poor. The mean range of flexion was 110°.

At 10 years the cumulative survival rate was 83% and at 15 years 78% (10 knees at risk). The “worst case scenario” where knees with pain or lost to follow up are added to revisions shows a 10 year survivorship of 74%.

Conclusion: Although the results are not as good as medial UKR. These clinical outcomes suggest that the conservative surgical procedure of lateral UKR with the fixed bearing St George Sled prosthesis can give acceptable results in the uncommon situation of severely symptomatic isolated lateral tibio femoral arthritis.

Purpose: To compare the ten-year survivorship results of an established total and medial compartment knee replacement performed in a single centre over an eighteen year period.

Method: Since 1978 knee replacements have been prospectively recorded in Bristol on a database. Regular clinical and radiological review has been undertaken every two or three years up to twenty years. 408 medial St Georg Unicompartmental replacements and 531 Kinematic total knee replacements have been subject to survivorship analysis using three failure end points. One - revision or removal of the implant. Two – revision or removal and moderate or severe pain. Three – the worst case including all patients lost to follow-up.

Results: The follow-up rate was 97% in both groups. 212 patients (562 knees) died and 31 patients (35 knees) were lost to follow-up. At ten years 25 medial Sled and 20 Kinematic knee arthroplasties had been revised. There was no significant difference (p > 0.05) in the number of good and excellent results. The mean range of movement at the last follow-up was 109 degrees for the medial Sled and 100 degrees for the Kinematic (p< 0.01). 94% of the medial Sled patients obtained a range of movement equal to or greater than 90 degrees whereas only 84% of Kinematic patients obtained this range (p < 0.05).

The ten-year survivorship figures were similar for both groups. Revision as the end point was 87.5% for the medial Sled and 89.6% for the Kinematic knees. When moderate and severe pain was considered in addition to revision ten-year survivorship was 79.4% in both groups. The worst case survivorship was also 74% in both groups.

Conclusion: The ten-year survivorship results of a fixed bearing, non-congruous, Unicompartmental arthroplasty are as good as those of a total knee replacement when performed in a single centre by two consultant surgeons and a variety of trainees. The advantages of a more rapid recovery and better quality result are offset by an easier though slightly higher revision rate.