There is conflicting evidence about the merits of mobile bearings in total knee replacement, partly because most randomised controlled trials (RCTs) have not been adequately powered. We report the results of a multicentre RCT of mobile versus fixed bearings. This was part of the knee arthroplasty trial (KAT), where 539 patients were randomly allocated to mobile or fixed bearings and analysed on an intention-to-treat basis. The primary outcome measure was the Oxford Knee Score (OKS) plus secondary measures including Short Form-12, EuroQol EQ-5D, costs, cost-effectiveness and need for further surgery.

There was no significant difference between the groups pre-operatively: mean OKS was 17.18 (sd 7.60) in the mobile-bearing group and 16.49 (sd 7.40) in the fixed-bearing group. At five years mean OKS was 33.19 (sd 16.68) and 33.65 (sd 9.68), respectively. There was no significant difference between trial groups in OKS at five years (-1.12 (95% confidence interval -2.77 to 0.52) or any of the other outcome measures. Furthermore, there was no significant difference in the proportion of patients with knee-related re-operations or in total costs.

In this appropriately powered RCT, over the first five years after total knee replacement functional outcomes, re-operation rates and healthcare costs appear to be the same irrespective of whether a mobile or fixed bearing is used.

Cite this article: Bone Joint J 2013;95-B:486–92.

Introduction

There is conflicting evidence about the merits of using mobile bearings at total knee replacement (TKR), partly because most randomised controlled trials (RCTs) have not been adequately powered.

Purpose: The purpose of this study was to report the mid-term survival results of Oxford UKAs in patients of 50 years of age or less, using (1) revision surgery and (2) Oxford Knee Scores (OKS) as outcome measures.

Method: A literature review identified studies of Oxford mobile bearing UKAs containing individuals 1) 50 years old or less with 2) medial osteoarthritis and 3) 2 years or longer follow-up. Authors were approached to participate in a multi-centre survival analysis by submitting all their patients, 50 years of age or less, who received a medial UKA for osteoarthritis. Patients who had died, been lost to follow-up or who underwent revision were identified. OKS were established for all patients with surviving implants.

Results: Seven centres submitted 107 patients. The mean age was 47 years (range 32–50). The average follow-up was 4 years (range 1–25). Forty-seven patients had follow-up into their fifth year or longer. The cumulative 7-year survival using revision as the endpoint was 96% (CI 8). The mean post-operative OKS for surviving implants was 38 (CI 2) out of a possible 48.

Conclusion: While early survival rates and function are encouraging, long-term follow-up is required before concluding UKA is a viable treatment option in young patients with unicompartmental knee arthritis.

129 knees suitable for a standard PCL retaining cemented total knee replacement were randomised into two groups, one in which PCL was retained in the normal way, the other group having the PCL fully resected. Both groups received a PCL retaining implant. The two groups were well matched with a predominance of females and a mean age of 67 years.

There was no statistically significant difference in the HSS scores at an average of 57 months (range 56–60 months) in the two groups. Pain relief, deformity correction, range of motion, stability and strength were comparable in the two groups. A radiological assessment revealed femoral rollback in approximately 20% of cases with a slightly higher incidence in the PCL sacrificed group. There was no significant loosening detected in either of the categories at two years review.

At five years one TKR in the PCL retained group has been revised due to an infection and one each in the two groups are awaiting revision surgery for loosening. Our findings have shown that there is no significant difference in the 5 year results of a PCL-retaining total knee replacement if the PCL is excised or preserved. This suggests two significant points:

the PCL is not functional in most patients with a total knee replacement even when retained:

Introduction: Total Knee Replacement (TKR) is a routine and common orthopaedic operation. Approximately 600 TKRs are performed annually at Royal Bournemouth Hospital. Although contemporary advice is that these patients should have long-term follow-up, there is very little evidence to support this protocol that involves considerable resources. We have had a policy of early discharge from follow-up (6–12 weeks) for over 10 years.

Purposes of the study: To validate the efficacy of the policy of early discharge after total knee arthroplasty at 8–10 years post surgery and to identify whether this policy has made revision surgery more difficult or complex as a result of possible late presentation.

Methods: 798 consecutive patients who underwent primary Total and Unicompartmental knee arthroplasy at Royal Bournemouth Hospital during the period 1 April 1994 to 31 March 1996 were identified. Medical records and operative notes were analysed for all patients from this cohort who have had any further surgery on their index knee. The waiting lists were also checked to identify patients from this cohort waiting for further surgery.

Results: The mean age at index operation was 72 years (range 37 to 92 years). 39/798 patients (4.9%) have had revision surgery at 8–10 years follow-up. Many of the revisions were performed on patients with early problems and 15/39(38%) of the revisions were performed on patients who were rereferred to clinic. There was a 1.1% deep infection rate leading on to revision (9 knees).

8/39 of revisions were for resurfacing the patella (20%). One patient who had a complex patella fracture needing patellectomy later had further revision surgery for instability requiring posterior stabilised components. In no patient was the revision surgery compromised or made reconstructable due to delayed presentation. In total 3 patients required bone grafting of contained cavities and only 5 knees with aseptic loosening required revision implants with stems.

Conclusion: We do not accept the need for long-term follow-up of successful implants especially whilst using prostheses with a proven track record in elderly patients.

2 stage revisions of infected knee replacements using a static spacer are complicated by poor patient mobility between stages and the need for extensive soft tissue releases at the second stage. In this study we hypothesised that the use of the resterilsed components as temporary functional spacers, maintains patient function, and reduces soft tissue releases at second stage without reducing the rate of septic failure and obviating the need for expensive purpose made spacers.

Method We report our series of seven two-stage revisions of infected total knee replacements using the resterilised femoral and tibial components as a temporary articulating spacers. This was compared to a second cohort of 6 patients in which the standard “hamburger” static spacer was used. Outcomes measured include reinfection rates, interval mobility, final range of movement, and bone loss.

Results The articulating spacer allowed more comfortable function between stages and obviated the need for rectus snips and tibial tubercle osteotomies for exposure at the second stage. There was less bone loss in the articulating group requiring less stems or augments. The range of movement averaged 88 degrees at 9.3 months compared to 80 degrees at 9.2 months in the “static” cohort. There were no reinfections in either group.

Discussion We have shown that this is a safe and effective way of treating infected knee arthroplasties with significant advantages for the surgeon and patient over more traditional methods.

Aims: We performed a prospective randomised controlled clinical trial of a comparison of PCL excison and PCL retention whilst using a standard PCL retaining cemented PFC knee relacement in order to answer two questionsòa) is the PCL functional if retained in PCL retaining TKRs. b) does PCL excison affect the results of a standard PCL retaining knee replacement. Methods: 129 knees suitable for a standard PCL retaining cemented total knee replacement were randomised into two groups, one in which the PCL was retained in the normal way, the other group having the PCL fully resected. Both groups received a PCL retaining implant. The two groups were well matched with a predominance of females and a mean age of 67 years. Results: There was no statistically significant difference in the HSS scores at an average of 57 months in the two groups. Pain relief, deformity correction, range of motion, stability and strength were comparable in the two groups. A radiological assessment revealed significant rollback in approximately 20% of cases with a slightly higher incidence in the PCL sacrificed group. There was no significant loosening detected in either of the categories at two years review. At five years one TKR in the PCL retained group has been revised due to an infection and one each in the two groups are awaiting revison surgery for loosening. Conclusions: Our findings have shown that there is no significant difference in the 5 year results of a PCL retaining total knee replacement if the PCL is excised or preserved. This suggests two significant points –a) the PCL is not functional in most patients with a total knee replacement even when retained. b) patients with excised PCLs show good results with PCL retaining implants, thereby questioning the need for posterior stabilised designs in all such cases.

Aims: We performed a prospective study on 105 knees following a selective approach to patellar resurfacing in cruciate retaining total knee replacements, and report the þve year results of both groups. Methods: We performed a prospective study on 129 knees with a selective approach to patellar resurfacing. 105 knees were followed up at an average of 57 months. Of these, forty eight knees met the eligibility criteria, thus leaving 57 knees with unresurfaced patellas. Mean follow up was 57 months. Parameters studied included HSS scores, pain, function, range of motion and patellofemoral symptoms including the ability to rise from a chair and to negotiate stairs. Results: Approximately 90% good to excellent results were observed in both groups. The incidence of anterior knee pain and patellofemoral related problems was lower than the average reported in literature. None of the knees was revised for patellofemoral problems. Conclusions: Our þndings suggest that the results of patellofemoral resurfacing with modern TKR designs are dependent on a careful patient selection and meticulous surgical technique. With a selective approach to resurfacing, one can achieve a high percentage of good results in both groups. Post operative anterior knee pain is probably not related to the fact as to whether the patella is resurfaced or not.

Aims: To compare the lateral vs medial approaches for TKRs in valgus knees. Methods: 67 knees (59 patients) with a valgus deformity of more than 10° suitable for total knee replacement were randomised to two different approaches. One group (36 knees) had their knees replaced by the standard medial para-patellar approach, whilst the other (31 knees) received a modified lateral approach (without an osteotomy of the tibial tubercle and with repositioning of the contracted vastus lateralis). Both groups were well matched with a predominance of females and mean age of 66.2 years. Average follow up was 28 months. Patients were assessed both pre and post operatively by the HSS (Hospital for Special Surgery) and Oxford knee scores, radiologically by weight bearing AP and lateral radiographs and by patient satisfaction scores on a scale of 10. Results: The mean pre operative HSS and Oxford scores for the medial group were 36.0 and 46.6 respectively and for the lateral group were 35.3 and 46.3 respectively. The mean post operative HSS and Oxford scores for the medial group were 77.4 (mean improvement of 41.4 points) and 26 respectively and for the lateral group was 81.2 (HSS score, mean improvement of 45.9 points) and 26.8 (Oxford score). 79.4% of patients in the medial group and 88% of patients in the lateral group showed good to excellent results (using the HSS scoring system)At two years none of the knees were radiologically loose, mal aligned or showed any evidence of an avascular necrosis. Average patient satisfaction on a scale of 10 was 7.9 for the medial group and 8.5 for the lateral group. One patient reported no relief of pain and an acute limitation of function at two years. She suffers from severe Parkinson’s disease and disabilities arising from multiple joint pathologies. There was no incidence of an early/ late infection. Pain relief, range of motion and deformity correction were comparable in the two groups. Conclusions: Our findings so far have shown that at an average of two and half years there seem to be better results in the group which had a lateral approach. However, this was not statistically significant. There are certain operative difficulties that can be overcome by using the lateral approach. Also, the incidence of the requirement of a stage II lateral release (release of the fibular collateral ligament and the popliteus) was found to be lower in the knees approached laterally. There was no need for any type of prosthetic constraint. Only one case of post operative valgus instability was seen in a lady suffering from severe Parkinsonism. This is a prelimnary report on a study now containing 97 patients.

We report a prospective study of the feasibility of employing specially trained physiotherapists to screen neonates for congenital dislocation of the hip. During ten years 42,241 babies were screened, using clinical tests; 255 were diagnosed and treated by a Pavlik harness. In the same period 13 children presented late with congenital dislocation of the hip which had not been detected by the screening programme.

Two cases of delayed median nerve division after laceration of the wrist by glass are described. In both there was no neurological damage at the time of the original injury. However, retained fragments of glass were subsequently responsible for division of the median nerve in both cases and of the surrounding tendons in one. Radiographs were an important diagnostic aid in treating the delayed injury.

A 21-year-old female athlete presented with bilateral lumps in her calves which became painful on exercise. Exploration revealed entrapment of the superficial peroneal nerves. Her symptoms were relieved by fasciectomy.

Despite widespread use of gentamicin beads in the treatment of chronic infections of bone and soft tissue, no serious complications have been reported. This report describes a rupture of the femoral vein which occurred during the attempted removal of a chain of beads after radical excision of a chronically discharging Girdlestone arthroplasty. The patient later had a disarticulation at the hip. In the light of our experience with this and other cases we offer some suggestions as to the positioning of gentamicin beads, as well as the timing and method of their extraction.

Fracture separation of the capital femoral epiphysis occurring during attempted closed reduction of a traumatic dislocation of the hip is described in two adolescents. Although this complication is extremely rare, the prognosis of fracture separation with dislocation of the epiphysis is known to be poor. Avascular necrosis subsequently developed in both cases. The importance of gentle manipulative reduction under general anaesthesia with complete muscle relaxation is emphasised.