Introduction: There is an impression among Orthopaedic surgeons that mobile bearing knee replacement has a better functional outcome than fixed bearing knee replacement. Since kneeling demands a high level of function after knee replacement this study was undertaken to see if mobile bearings in either total or unicompartmental replacement conferred an advantage.

Methods: A prospective randomised study of 207 TKR patients receiving the same prosthesis (Rotaglid, Corin, UK) was performed. Patients were randomised into a mobile bearing group (102 patients with a mean age of 53 years) and a fixed bearing group (105 patients with a mean age of 55 years). Data was also prospectively collected on 215 UKR patients who received the same unicompartmental implant (AMC, Uniglide, Corin, UK). 136 patients (Mean age: 62 yrs) had a mobile insert and 79 (mean age: 65 yrs) a fixed insert.

All patients completed the Oxford Knee Questionnaire preoperatively as well as at 1 and 2 years postoperatively. Their stated kneeling ability and total scores were analysed with a perfect score for kneeling ability being 4, and 48 the maximum total score.

Results: In all groups both the kneeling ability and the total scores improved markedly from their preoperative state. At two years the total score for the fixed bearing devices was marginally better than for the mobile (Rotaglide 36;31 and Uniglide 37;33)

There was a more striking difference with respect to kneeling ability with the fixed bearing variants performing better, (Rotaglide 1.4; 0.9 and Uniglide 1.9; 1.4), However, the greatest difference was between the UKR and TKR groups (UKR 1.7; TKR 1.2). Pre-operatively less than 2% of TKR patients (7% of the UKR patients) could kneel. Post-operatively, the patients’ kneeling ability improved with 21% for the mobile bearing, 32% of fixed bearing UKR patients. The TKR patients kneeling ability was 13% of the mobile, 26% of fixed bearing patients were able to kneel with little or no difficulty. In all groups the stated kneeling ability was poor with less than 50% of any group being able to kneel with ease or only minor difficulty.

Conclusion: Those undergoing UKR appeared to perform better than those with a TKR. None of the forms of knee replacement used resulted in good kneeling ability, though this function was improved by arthroplasty in all groups. Mobile bearing inserts

Purpose: Revision patellofemoral arthroplasty (PFA) is a relatively uncommon procedure, with no published reviews identified in the literature. Revision PFAs performed at our institution were reviewed to determine the reasons for PFA failure, the technical ease of revision and to document patient-reported outcomes after revision.

Methods: A prospective review of a cohort of 411 Avon PFA patients identified 31 subsequent revision knee procedures in 27 patients. Data was collected from the institution’s prospective data base, operative reports, X-rays and medical records. Post-operative knee scores (Oxford Knee Score, WOMAC Osteoarthritis Index, Bristol Knee Score) were available on 26 knees.

Results: The commonest reason for revision was progression of osteoarthritis (18 cases) followed by undetermined pain (7 cases). Patients with undetermined pain were found to be revised sooner than patients with disease progression (33 months vs 63 months) and also reported poorer outcome scores at 2 years post revision than the disease progression group.

Only two trochlea components were loose at the time of revision and one patella had a large amount of macroscopic wear. All other components were found to be well fixed with minimal wear at the time of revision. There were no difficulties in removing either component. No cases required augments or stemmed femoral components due to bone loss.

Patients undergoing revision surgery did report improvement in their post revision outcome scores compared with their pre-operative scores. The average Oxford Knee Score improved from 17 to 23, Bristol Knee Pain Scores improved from 11 to 20 and Bristol Knee Functional Scores improved from 15 to 16. These results are poorer than those recorded by the overall cohort of primary PFA.

Conclusion: PFA is easy to revise to a primary total knee. Results of revision knees are improved from pre-operative scores but not as good as expected.

Introduction: There is an impression among Orthopaedic surgeons that mobile bearing knee replacement has a better functional outcome than fixed bearing knee replacement. Since kneeling demands a high level of function after knee replacement this study was undertaken to see if mobile bearings in either total or unicompartmental replacement conferred an advantage.

Methods: A prospective randomised study of 207 TKR patients receiving the same prosthesis (Rotaglid , Corin, UK) was performed. Patients were randomised into a mobile bearing group (102 patients with a mean age of 53 years) and a fixed bearing group (105 patients with a mean age of 55 years).

Data was also prospectively collected on 215 UKR patients who received the same Unicompartmental implant (AMC, Uniglide, Corin, UK). One hundred and thirty six patients (Mean age: 62 yrs) had a mobile insert and 79 (mean age: 65 yrs) a fixed insert.

All patients completed the Oxford Knee Questionnaire preoperatively as well as at 1 and 2 years postoperatively. Their stated kneeling ability and total scores were analysed with a perfect score for kneeling ability being 4 and 48 the maximum total score.

Results: In all groups both the kneeling ability and the total scores improved markedly from their preoperative state. At two years the total score for the fixed bearing devices was marginally better than for the mobile (Rotaglide 36;31 and Uniglide 37;33)

There was a more striking difference with respect to kneeling ability with the fixed- bearing variants performing better, (Rotaglide 1.4; 0.9 and Uniglide 1.9; 1.4), However, the greatest difference was between the UKR and TKR groups (UKR 1.7; TKR 1.2). Pre-operatively less than 2% of TKR patients (7% of the UKR patients) could kneel. Post-operatively, the patients’ kneeling ability improved with 21% for the mobile bearing, 32% of fixed bearing UKR patients.

The TKR patients kneeling ability was 13% of the mobile, 26% of fixed bearing patients were able to kneel with little or no difficulty. In all groups the stated kneeling ability was poor with less than 50% of any group being able to kneel with ease or only minor difficulty.

Conclusion: Those undergoing UKR appeared to perform better than those with a TKR. None of the forms of knee replacement used resulted in good kneeling ability, though this function was improved by arthroplasty in all groups. Mobile bearing inserts did not confer any advantage with respect to kneeling and in fact performed worse with regard to this particular knee function.

Objective: To review the results of the Avon patellofemoral arthroplasty at 5 to 8 years.

Methods: The Avon patellofemoral arthroplasty was introduced in clinical practice in September 1996. We present a prospective cohort review of all patients treated in the first three years. Patients were evaluated using the Bristol knee score (BSK), the Melbourne patella score (MPS) and the Oxford knee score (OKS).

Results: 109 patellofemoral arthroplasties were performed in 92 patients between September 1996 and November 1999. The median age was 68 years (range 46 to 86 years). Nine patients (12 knees) died and two patients (two knees) were unfit for follow-up. Ten knees in 9 patients were lost to follow-up giving a follow-up rate of 89%. The mean period of follow-up was 5.6 years.

The median pain score rose from 15/40 pre-operatively to 40 points at eight years. The median (MPS) rose from 10/30 points pre-operatively to 25 points at eight years. The median (OKS) rose from 18/48 pre-operatively to 38 at eight years. 87% of knees had mild or no pain at eight years. There were no cases of failure of the prosthesis itself. All 15 revisions resulted from progression of arthrititis in the tibio-femoral joint. The five-year survival rate for all causes with 86 cases at risk was 96%.

Conclusions: The results show that this type of arthroplasty can give predictable pain relief and excellent functional improvement in patients with isolated patello-femoral arthritis. Disease progression is the main reason for revision to total knee replacement and great care is required in assessing the indications for this procedure.

Introduction: Anterior Knee pain is a very common presentation in Orthopaedic out patient clinics. However, Trochlear Dysplasia as a condition is still not very well understood.

Materials and Methods: Operative findings in patients undergoing Trochleaplasty and in young patients undergoing Patella-femoral arthroplasty were studied. Patients having trochlear dysplasia were identified. All these patients were sent a questionnaire to explore the variety of symptoms they experienced. 87 patients were identified for the study. 71(82%) patients responded to the questionnaire.

Results: Two subgroups were identified, one with dislocation of patella and the other without dislocation of the patella. Patients in patella dislocation group were younger (12 years vs 24) than those who presented without dislocation of patella. Patella dislocation group had more patients with anterior knee pain (71% vs 52%) as teenagers as compared to the group without dislocations. Symptoms such as giving way, lack of trust and unable to participate in sports were more commonly seen in the group with patella dislocation whereas, limited walking distance and difficulty with climbing the stairs were more commonly seen in the group without dislocation. Symptoms such as pain, catching and locking were seen equally amongst the two groups.

Conclusion: We believe that the patients with trochlear dysplasia have a bimodal presentation. Patients with dislocation of patella present earlier than those without patella dislocation. These two groups also have different symptoms at presentation. It is important to identify these subgroups correctly for appropriate management.

Purpose of Study: Fixed bearing unicompartmental knee replacement (UKR) has become popular since several series have shown good 10 year survivorship and excellent function. However little is known about survival during the second decade.

Method: From the Bristol database of over 4000 knee replacements 203 St. George Sled UKR’s which had already survived 10 years were identified. The mean age at surgery was 67 years (48–85), with 64% being female. This cohort has been further reviewed at an average of 14.8 years (10–30) from surgery to determine survivor-ship and function.

Results: Survivorship during the second decade was 87.5%. 58 patients (69 knees) had deceased with implant in situ, only 2 after revision. A further 15 UKR’s have been revised at an average of 13 years post op; 7 for progression of disease, 4 for tibial loosening, 3 for polyethylene wear, 2 for femoral component fracture and 2 for infection.

99 knees were followed for 15 years and 21 knees for 20 years. The average Bristol knee score of the surviving knees fell from 86 to 79 during the second decade.

A previous study showed an 89% 10 year survivor-ship and this is now extended to 82% at 15 years and 76.5% at 20 years.

Conclusion: Satisfactory survival of fixed bearing UKR can be achieved in the second decade suggesting that the indications for mobile bearings require careful definition since there is a higher incidence of complications in many people’s hands.

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.

Introduction: Following previously gratifying results in older patients the study aims to quantify the outcomes and identify any contraindications in patient selection for patello-femoral replacements using the Avon pros-thesis in patients under 55 years old.

Method: We present early outcome results for a prospective cohort study of patients under 55 years of age.110 knees in 86 patients (median age 47years, range 25–54) have been treated with Avon patello-femoral replacement (88 in females and 22 in males). Diagnoses included lateral facet OA (59 knees), patella dislocation (36 knees), trochlear dysplasia (39 knees) and post patellectomy instability (7 knees). 108 knees had undergone previous surgery. 14 knees required additional intra-operative procedures (including 11 lateral releases and 2 patella realignments). All patients were assessed pre-operatively using the Oxford, Bristol and WOMAC scores.

Results: No knees have been lost to follow-up. 82 knees have post operative scores available (mean follow-up 27 months). 8 have been revised (6 due to progression of OA). The mean Oxford, Bristol and WOMAC scores all improved: 18 to 32, 56 to 83 and 39 to 25 respectively. Asymptomatic deterioration of the tibio femoral joint is seen in some cases of primary OA but not with trochlear dysplasia. 21 knees required post-operative additional procedures including 6 lateral releases, 3 patella realignments and 5 revisions. Equally good results were seen when comparing patients with the 3 main diagnoses. Trochlear dysplasia is strongly predicted by young age at onset of symptoms and patellar dislocation.

Conclusion: Many of this type of patient, with disabling symptoms, wish to “live now”. The short-term improvements are frequently dramatic. Comparison of underlying pathologies has not identified groups that are performing less well to suggest restricting current indications. As yet there is no suggestion of prosthetic failure. Revision has presented little difficulty since minimal bone is resected primarily.

We identified 148 patients who had undergone a revision total knee replacement using a single implant system between 1990 and 2000. Of these 18 patients had died, six had developed a peri-prosthetic fracture and ten had incomplete records or radiographs. This left 114 with prospectively-collected radiographs and Bristol knee scores available for study. The height of the joint line before and after revision total knee replacement was measured and classified as either restored to within 5 mm of the pre-operative height or elevated if it was positioned more than 5 mm above the pre-operative height. The joint line was elevated in 41 knees (36%) and restored in 73 (64%).

Revision surgery significantly improved the mean Bristol knee score from 41.1 (sd 15.9) pre-operatively to 80.5 (sd 15) post-operatively (p < 0.001). At one year post-operatively both the total Bristol knee score and its functional component were significantly better in the restored group than in the elevated group (p < 0.01). Overall, revision from a unicondylar knee replacement required less use of bone graft, fewer component augments, restored the joint line more often and gave a significantly better total Bristol knee score (p < 0.02) and functional score (p < 0.01) than revision from total knee replacement.

Our findings show that restoration of the joint line at revision total knee replacement gives a significantly better result than leaving it unrestored by more than 5 mm. We recommend the greater use of distal femoral augments to help to achieve this goal.

We report the mid-term results of a new patellofemoral arthroplasty for established isolated patellofemoral arthritis. We have reviewed the experience of 109 consecutive patellofemoral resurfacing arthroplasties in 85 patients who were followed up for at least five years.

The five-year survival rate, with revision as the endpoint, was 95.8% (95% confidence interval 91.8% to 99.8%). There were no cases of loosening of the prosthesis. At five years the median Bristol pain score improved from 15 of 40 points (interquartile range 5 to 20) pre-operatively, to 35 (interquartile range 20 to 40), the median Melbourne score from 10 of 30 points (interquartile range 6 to 15) to 25 (interquartile range 20 to 29), and the median Oxford score from 18 of 48 points (interquartile range 13 to 24) to 39 (interquartile range 24 to 45). Successful results, judged on a Bristol pain score of at least 20 at five years, occurred in 80% (66) of knees. The main complication was radiological progression of arthritis, which occurred in 25 patients (28%) and emphasises the importance of the careful selection of patients. These results give increased confidence in the use of patellofemoral arthroplasty.

There have been several reports of good survivorship and excellent function at ten years with fixed-bearing unicompartmental knee replacement. However, little is known about survival beyond ten years.

From the Bristol database of over 4000 knee replacements, we identified 203 St Georg Sled unicompartmental knee replacements (174 patients) which had already survived ten years. The mean age of the patients at surgery was 67.1 years (35.7 to 85) with 67 (38.5%) being under 65 years at the time of surgery. They were reviewed at a mean of 14.8 years (10 to 29.4) from surgery to determine survivorship and function. There were 99 knees followed up for 15 years, 21 for 20 years and four for 25 years. The remainder failed, were withdrawn, or the patient had died.

In 58 patients (69 knees) the implant was in situ at the time of death. Revision was undertaken in 16 knees (7.9%) at a mean of 13 years (10.2 to 21.6) after operation. In seven knees (3.4%) this was for progression of arthritis, in three (1.5%) for wear of polyethylene, in four (2%) for tibial loosening, in two (1%) for fracture of the femoral component and in two (1%) for infection. Two knees (1%) were revised for more than one reason.

The mean Bristol knee score of the surviving knees fell from 86 (34 to 100) to 79 (42 to 100) during the second decade. Survivorship to 20 years was 85.9% (95% CI 82.9% to 88.9%) and at 25 years was 80% (95% CI 70.2% to 89.8%). Satisfactory survival of a fixed-bearing unicompartmental knee replacement can be achieved into the second decade and beyond.

Aim: To assess the results of aseptic and aseptic cases using the PFC/TC3 system, and to correlate this with the restoration of joint line height.

Method: 148 patients underwent revision TKR using the PFC/TC3 system. No re-revision cases were included in this series. Data was prospectively collected (using the Bristol Knee Score) pre-operatively and at a mean of 4.2 years post-revision. 31 revisions were for infection and 53 revisions were for aseptic loosening. Revision for infection was done as a two-stage procedure and aseptic as a single operation. Measurements of the joint line height were made pre and post-operatively using Figgie’s method. The cases were divided into 3 groups on the basis of joint line restoration:

Lowered by more than 5 mm

Results: The mean pre-op total score for the infection group was 35/100 and 40/100 for the aseptic loosening group. The total score post-operatively was 67 for the infection group and 73 for the aseptic loosening group. The joint line was restored in 50% of infected cases and in 60% of aseptic loosening cases.

Conclusion: although the overall results were slightly less satisfactory for the infected revision group, there was no significant difference between the two groups either in total BKS scores or in reproduction of the joint line. The average outcome was much less good than for primary TKR.

Purpose of study: To examine the fate of the non operated on compartment of the knee, following unicompartmental knee replacement (UKR), by radiological assessment 10 years after operation.

Summary of methods and results: A total of 50 UKRs were performed on 45 carefully selected patients between 1989 and 1992. Fifteen patients died, two patients were lost to follow-up and two knees were revised. The radiographs of the remaining 30 knees were reviewed three times by blind and randomised assessment using Ahlback and Altman scoring systems to measure the progression of osteoarthritis within the joints. Standard long-leg weight-bearing anteroposterior views of the knee and skyline views of the patello-femoral joint were taken before, at eight months and ten years after operation. Two knees showed evidence of progression of osteoarthritis within the patello-femoral joint and three knees showed some progression of the opposite tibio-femoral compartment.

Statement of conclusion: Our study provides evidence that after ten years progressive OA within the retained compartments following UKR is rare and usually minor.

Introduction: Correct prosthesis alignment and joint line reproduction in total knee replacement (TKR) is vital for a successful clinical outcome. It is acknowledged that the ideal coronal alignment of the knee following TKR should be between 4–10 degrees of valgus. A neutral or varus knee is associated with a higher failure rate. Previous studies have shown that ideal alignment is achieved in only around two-thirds of cases.

Joint line elevation > 8mm has been associated with inferior clinical outcome, and depression associated with retropatellar pain and increased risk of patella subluxation.

Recently, modifications have been made to the Kine-max-Plus Total Knee System instrumentation, theoretically providing better internal fixation to prevent a varus cut and a 12 mm measured resection from the “normal” tibial plateau. This study aims to examine whether these changes result in an improvement in alignment, and a more reliable restoration of joint line.

Materials and Methods: Two consecutive series, each of 75 patients who had undergone TKR using either the old (Group A) or the new (Group B) instrumentation were included in the study. Antero-posterior and lateral preoperative and postoperative knee radiographs were assessed using the American knee society radiographic analysis for prosthesis postionoing by 2 independent observers. The Tibial and Femoral Component Angles in the coronal plane (cTCA and cFCA) and in the sagittal plane (sTCA and sFCA) were measured, as was the change in joint line height.

Conclusion: Our results suggest that use of the new instrumentation is associated with better restoration of joint line, and is more effective in preventing implantation of the tibial component in varus. These figures relating to a modern instrumentation system provide a yardstick against which computer assisted and robotic surgery can be judged. Long-term follow-up will be required to assess the clinical significance of these results.

Purpose: To assess the outcome of customised hinged knee replacements when used to salvage catastrophically failed knee replacements in elderly patients.

Methods: Since 1993, 30 of the 280 (10.7%) revision knee replacements at the Avon Orthopaedic Centre, Bristol have used Endo customised hinged knee pros-theses (21 rotating, 9 fixed) for salvage of limb threatening situations in elderly patients. All were prospectively recorded and regularly reviewed. The average age was 75 years with a predominance of females. Surgical indications were 22 periprosthetic fractures (with or without aseptic loosening), 5 massive aseptic osteolyses, and 3 deep infections.

Results: The mean length of postoperative hospital stay was just 14.6 days and all patients were discharged walking with aids. At follow up (mean 3.0 years, range 0.5–9.3 years) 9 patients had died with their prostheses in situ and functioning. 2 had undergone amputation for recurrent sepsis and 2 had received further surgery for septic problems. 2 patients required further surgery for prosthetic disarticulation and one patient had successful on table vascular repair. 25 patients had mid or long term follow up. Their mean American Knee Scores (AKS) were 69.8 for knee and 35.6 for function (maximum 100), with a mean total knee flexion of 83 degrees. Mean Oxford knee scores (OKS) and WOMAC scores (both scored between 12 and 60 with low score indicating less difficulties) were 34.0 and 30.5 respectively.

Conclusions: Customised hinge revision knee replacements gave extremely rapid rehabilitation and hospital discharge which justified the high prosthetic cost. Complications were high but at mid and long-term review, no prostheses had failed from an aseptic cause and most of the knees of this challenging group were providing both stability and flex

Following total hip arthroplasty (THA) and total knee arthroplasty (TKR) only the ‘visible’ measured blood loss is usually known. This underestimates the ‘true’ total loss, as some loss is ‘hidden’. Correct management of blood loss should take hidden loss into account.

We studied 101 THAs and 101 TKAs (with re-infusion of drained blood). Following THA, the mean total loss was 1510 ml and the hidden loss 471 ml (26%). Following TKA, the mean total loss was 1498 ml. The hidden loss was 765 ml (49%). Obesity made no difference with either operation.

THA involves a small hidden loss, the total loss being 1.3 times that measured. However, following TKA, there may be substantial hidden blood loss due to bleeding into the tissues and residual blood in the joint. The true total loss can be determined by doubling the measured loss.

Purpose A new design of patello-femoral arthroplasty has been used to treat patients under 55 years suffering severe symptoms from chondral and early arthritic disease of the patello-femoral joint.

Materials and Methods and Results Fifty-two patello-femoral arthroplasties were performed in 45 patients under the age of fifty-five years when other treatments had failed. The average age was 48 years (range 36–54 years). Thirty-seven cases had undergone previous surgery for a variety of conditions, and the causes of the disorders were analysed. Results were assessed using pain scores and Bartlett’s and Oxford functional scores. 35 cases were reviewed at 8 months and 22 cases at two years. The median pain score improved from 10/40 points to 35 at two years. The Bartlett score increased from 10/30 points to 27 and the Oxford score from 19/48 points to 35 at two years. The range of movement increased from 114° to 121°. There have been no cases of deep infection, loosening, wear or instability. Disease progression, a potential risk has occurred in one case.

Conclusions This prosthesis offers a solution in younger patients with disabling symptoms of isolated early patello-femoral disease who have not responded to conservative surgical management.

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 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.

Nine patients underwent arthrodesis of the knee using a customised coupled nail (the Mayday arthrodesis nail), five after infected arthroplasty, one following failed arthrodesis, one for intractable anterior knee pain, one for Charcot instability and one after trauma. Comparison was made with 17 arthrodeses, eight undertaken using external fixation, four with dual compression plates, and five with long Küntscher nails. Union was achieved in all patients (100%) at a mean time of ten months using the customised implant. There were no complications despite early weight-bearing. No further procedures were required. This contrasted with a rate of union of 53% and a complication rate of 76% with alternative techniques. Of this second group, 76% required a further operative procedure.

We compared the Mayday arthrodesis nail with other techniques of arthrodesis of the knee. The differences in the need for further surgery and occurrence of complications were statistically significant (p < 0.001), and differences in the rate of nonunion and inpatient stay of less than three weeks were also significant (p < 0.05) using Fisher’s exact test.

We conclude that a customised coupled intramedullary nail can give excellent stability allowing early weight-bearing, and results in a high rate of union with minimal postoperative complications.

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.

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.

We describe 88 knees (79 patients) with lateral unicompartmental osteoarthritis which had been treated by the St Georg Sled prosthesis.

At a mean follow-up of nine years (2 to 21) 15 knees had revision surgery, nine for progression of arthritis, six for loosening, four for breakage of a component and four for more than one reason. Six patients complained of moderate or severe pain at the final follow-up. Only five knees were lost to follow-up in the 21-year period.

We performed survivorship analysis on the group using revision for any cause as the endpoint. At ten years the cumulative survival rate was 83%, and at 15 years, when ten knees were still at risk, it was 74%.

Based on our clinical results and survival rate the St Georg Sled may be considered to be a suitable unicompartmental replacement for isolated lateral compartment osteoarthritis.

Traditional dogma states that anterior knee pain in adolescence does not lead to patello-femoral arthritis. However analysis of 642 new knee referrals seen in one year showed that over 25% had anterior knee pain and that patients were of all ages. This lead to us questioning whether anterior knee pain or adolescent chondromalacia patellae is in fact a benign self limiting condition.

Method: A postal questionnaire was sent to 150 patients who had undergone isolated patello femoral replacement (PFR) enquiring about patella problems earlier in life. The same questionnaire was sent to a matched group of patients who had undergone unicompartmental replacement; because of the selection policy of the unit, these would not have had changes of patellofemoral arthritis.

Results: 118 patients who had undergone PFR retumed the form. 107 were female; the average age at surgery was 66 years. 26 (22%) reported adolescent anterior knee pain at an average age of 18. 112 forms were returned form the UKR group in which females predominated and who had an average age at surgery of 67 years. Only 7 (6%) reported adolescent anterior knee pain, at an average age of 19. 16 (14%) of the PFR group reported adolescent patella instability as opposed to 1 on the UKR group.

Discussion: The finding that significantly more patients with isolated patello-femoral arthritis had suffered from adolescent anterior knee pain suggests a possible causal relationship. Further long-term studies are needed to determine whether adolescent anterior knee pain is benign, as traditionally believed, or whether certain subsets are precursors of patello-femoral arthritis.

Purpose: This study analyses the kneeling ability of patients following Unicompartmental knee replacement (UKR), Patellofemoral replacement (PFR) and Total knee replacement (TKR).

Method: Data was prospectively collected on 272 knees (254 patients) that had undergone various forms of arthroplasty procedures for osteoarthritis of the knee. All patients completed the Oxford Knee Questionnaire preoperatively and 1 year postoperatively, thus graded their kneeling ability into one of 5 categories. Absolute values and change following arthroplasty were recorded. In addition the reported kneeling ability of 75 patients was checked by clinical examination.

Results: Preoperatively only 2% of all patients could kneel with PFR group being more able than the others (UKR 0%, TKR 0% and PFR 6%). In all groups the kneeling ability was better one year following replacement than preoperatively (23% of UKR, 18% of TKR and 9% of PFR) being able to kneel with little or no difficulty.

Conclusions: No form of arthroplasty used resulted in good kneeling ability, though this function was always improved particularly by UKR. Good range of movement and younger age appeared to correlate with better kneeling ability but many patients thought they had been told not to kneel and reported less ability than they demonstrated on examination. Instruction to avoid kneeling seems unnecessary.

We have studied the long-term outcome of 408 primary medial St George Sled unicompartmental arthroplasties of the knee and 531 primary Kinematic total knee arthroplasties using survivorship analysis. The operations were performed by a number of surgeons under the supervision of two consultants at one orthopaedic centre. Prospective clinical assessment was carried out before and at 2, 5, 8, 10, 12 and 15 years after operation. Failure was defined as follows: revision or removal of the implant; the presence of moderate or severe pain; or ‘worst-case’ with all patients lost to follow-up.

Cumulative survival rates at ten years were calculated using life tables. The follow-up rate was 97%. At ten years, 25 medial sled arthroplasties and 20 Kinematic knee arthroplasties had been revised. With revision or removal as the survivorship endpoint at ten years there was a success rate of 87.5% for the medial sled and 89.6% for the Kinematic knee arthroplasty. When moderate or severe pain was included these rates became 79.4% for both arthroplasties. There was no statistically significant (p > 0.05) difference between the rates of survival for the two arthroplasties using either of the endpoint criteria.

Good or excellent results were recorded for 77.9% of the medial sled knees and 75.1% for the Kinematic knees. The former had 93.8% of cases with a final range of movement in excess of 90° compared with 83.7% for the Kinematic knees (p < 0.01). We conclude that at a single orthopaedic centre in the UK, the St Georg Sled medial compartment arthroplasty for appropriate specific indications offers predictable survivorship at ten years which is comparable with that of the Kinematic total knee arthroplasty.

We present a prospective review of the outcome of 76 Lubinus patellofemoral arthroplasties carried out in 59 patients between 1989 and 1995. At a mean follow-up of 7.5 years, 62 knees in the 48 patients were reviewed; 11 patients (14 knees) had died. None was lost to follow-up.

The clinical outcome using the Bristol Knee Scoring system was satisfactory in 45% of the cases. Maltracking of the patella, resulting in lateral tilt, subluxation and polyethylene wear, was the most common complication (32%). Revision surgery was carried out in 21 knees (28%) giving a cumulative survival rate of 65% (confidence interval (CI) 49 to 77) at eight years. The survival rate for revision and moderate pain was 48% (CI 36 to 59) at six years. Progression of arthritis was seen in seven cases (9%). In five of these (6.5%), the symptoms were severe enough to need revision surgery. Due to the high proportion of unsatisfactory results, we have discontinued the use of this prosthesis.

Failure of a unicompartmental knee replacement (UKR) may be caused by progressive osteoarthritis of the knee and/or failure of the prosthesis. Limb alignment can influence both of these factors. We have examined the fate of the other compartments and measured changes in leg alignment after UKR.

A total of 50 UKRs was carried out on 45 carefully selected patients between 1989 and 1992. At operation, deliberate attempts were made to avoid overcorrection of the deformity. Four patients died, one patient was lost to follow-up and two knees were revised before review which was at a minimum of five years. Standard long-leg weight-bearing anteroposterior views of the knee and skyline views of the patellofemoral joint were taken before and at eight months and five years after operation. The radiographs of the remaining 43 knees were reviewed twice by blind and randomised assessment to measure the progression of osteoarthritis within the joints. Overcorrection of the deformity in the coronal plane was avoided in all but two knees. Only one showed evidence of progression of osteoarthritis within the patellofemoral joint, and this was only identified in one of the four assessments. Deterioration in the state of the opposite tibiofemoral compartment was not seen. Varus deformity tended to recur. Recurrent varus of 2° was observed between eight months and five years after operation. There was no correlation between the postoperative tibiofemoral angle and the extent of recurrent varus recorded at five years. Changes in alignment may be indicative of minor polyethylene wear or of subsidence of the tibial component.

The incidence of progressive osteoarthritis within the knee was very low after UKR. Patients should be carefully selected and overcorrection of the deformity be avoided.

Patella infera may occur after reconstruction of the anterior cruciate ligament (ACL), high tibial osteotomy and total knee replacement (TKR). Restriction of movement of the knee and pain may result. Our aim was to compare the incidence and to assess the effects of patella infera after TKR and unicompartmental knee replacement (UKR).

We reviewed radiographs of the knees of 84 patients who had had either TKR or UKR as part of a randomised, controlled trial. The length of the patellar tendon was measured on serial radiographs taken before, at eight months and at five years after operation.

There was no significant change in the length of the patellar tendon after UKR, but a significant reduction was observed after TKR. Five years after the operation, the shortening of the tendon had increased to a mean of 3.5 mm. Of the knees with TKR reviewed at five years, 34% developed patella infera, defined as 10% or more of shortening, compared with 5% of those with UKR. Shortening was greatest in those knees which had required a lateral release; in this subgroup the mean shortening was 7.2 mm. Shortening correlated with restriction of movement and pain in the knee.

Our study has shown that patella infera develops in most patients after TKR with lateral release, and in approximately 25% of patients after TKR without this additional procedure. Patella infera rarely occurs after UKR. It is associated with restriction of movement and pain in the knee. It may be an effect of the more extensive exposure required to perform TKR and may, in part, explain the better clinical results of UKR.

We randomised 102 knees suitable for a unicompartmental replacement to receive either a unicompartmental (UKR) or total knee replacement (TKR) after arthrotomy. Both groups were well matched with a predominance of females and a mean age of 69 years.

Patients in the UKR group showed less perioperative morbidity, but regained knee movement more rapidly and were discharged from hospital sooner.

At five years, two UKRs and one TKR had been revised; another TKR was radiologically loose. All other knees appeared to be clinically and radiologically sound.

Pain relief was good in both groups but the number of knees able to flex ≥ 120° was significantly higher in the UKR group (p < 0.001) and there were more excellent results in this group.

Our findings have shown that UKR gives better results than TKR and that this superiority is maintained for at least five years.

We have carried out a randomised, controlled trial on 70 patients having unilateral total knee replacement in which transfusion was either with homologous bank blood or by reinfusion of unwashed blood salvaged after operation.

No complications or adverse effects were observed from reinfusion. The need for bank blood was reduced by 86% in the reinfusion group but, more importantly, the number of infective episodes was significantly less when the use of bank blood was avoided. The mean length of stay in hospital was also reduced by more than two days.