Impact of change of knee prosthesis on early clinical outcomes in a large volume arthroplasty centre.

INTRODUCTION: The aim of our study was to investigate the effect of changing the default knee prosthesis in a high volume dedicated arthroplasty unit from DePuy's PFC(®) Sigma(®) to Smith & Nephew's Genesis™ II. METHODS: A retrospective analysis was performed of prospective data on primary total knee replacements (TKRs) from January 2009 until December 2011. This provided information on the operative time, length of stay, pain at mobilisation, radiography analysis, any complications, and readmission at 30 and 60 days. RESULTS: The total numbers of primary TKRs using the PFC(®) and Genesis™ II prostheses were 1,061 and 1,268 respectively. The results showed a slight increase (maximum of five minutes) in the operative time for all the surgeons except one surgeon, whose operative time reduced by an average of seven minutes. There was no significant adverse outcome after the change in the knee implant. There was no clinically significant increase in the length of stay, pain at mobilisation or complication rates. There was a twofold increase in the wastage of the implant in the Genesis™ II group in the initial learning period. CONCLUSIONS: Through a competitive process of implant tendering, we have successfully introduced a new implant into a large elective orthopaedic unit. This has resulted in significant financial savings without adversely affecting our clinical practice or patient outcome.

Five-year results of a randomised controlled trial comparing mobile and fixed bearings in total knee replacement.

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.

Five year results of selective patellar resurfacing in cruciate sparing total knee replacements.

We performed a prospective study on 129 knees with a selective approach to patellar resurfacing. One hundred and five knees were followed up at an average of 57 months. Of these, 48 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. 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. Our findings 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.

The role of the posterior cruciate ligament in total knee replacement.

We randomised 129 knees which were to be replaced using a standard posterior-cruciate-ligament (PCL)-retaining cemented total knee replacement into two groups. In one the PCL was retained in the normal way and in the other it was resected. They were well matched, with a predominance of women, and a mean age of 67 years. There was no statistically significant difference in the Hospital for Special Surgery scores at a mean of 57 months (56 to 60) between the two groups although 21 patients (24 knees) were lost to follow-up. Relief from pain, correction of deformity, range of movement, stability and strength were comparable in both. Radiological assessment showed femoral rollback in approximately 20% of knees with a slightly higher incidence in the PCL-resected group. There was no significant loosening detected in either group at review at two years. At five years, one knee in the PCL-retained group had been revised because of infection and one patient in each group was awaiting revision for loosening. Our findings have shown no significant difference in the five-year results for a PCL-retaining total knee replacement if the PCL is excised or preserved. This suggests two important points. First, the PCL is not functional in most patients with a total knee replacement even when retained. Secondly, patients with an excised PCL show a good result with a PCL-retaining implant, thereby questioning the need for a posterior stabilised design in such a situation.

The use of a closed-suction drain in total knee arthroplasty. A prospective, randomised study.

We prospectively randomised 100 patients undergoing cemented total knee replacement to receive either a single deep closed-suction drain or no drain. The total blood loss was significantly greater in those with a drain (568 ml versus 119 ml, p < 0.01; 95% CI 360 to 520) although those without lost more blood into the dressings (55 ml versus 119 ml, p < 0.01; 95% CI -70 to 10). There was no statistical difference in the postoperative swelling or pain score, or in the incidence of pyrexia, ecchymosis, time at which flexion was regained or the need for manipulation, or in the incidence of infection at a minimum of five years after surgery in the two groups. We have been unable to provide evidence to support the use of a closed-suction drain in cemented knee arthroplasty. It merely interferes with mobilisation and complicates nursing. Reinfusion drains may, however, prove to be beneficial.

Wroblewski wedge augmentation for recurrent posterior dislocation of the Charnley total hip replacement.

We analysed 68 cases of acetabular augmentation using the Wroblewski wedge for recurrent posterior dislocation of Charnley total hip replacements inserted through a posterior approach. The follow-up was done by postal questionnaire in living patients or by thorough search of case notes in the dead. All hips were followed up either until death or a minimum of 2 years. The average follow-up for the surviving successful group was 35.3 months. Out of 68 hips, 52 (76%) had no further dislocation at a mean follow-up of 35.3 months (range, 24-95 months). An additional 4 hips became stable after one closed reduction for a re-dislocation. After a second augmentation, 5 more hips were stabilised. Wroblewski wedge augmentation is a simple and effective procedure and should be considered before embarking on major revisions in recurrent posterior dislocations in the elderly with no obvious cause for instability.

Replacement arthroplasty of the valgus knee. A modified lateral capsular approach with repositioning of vastus lateralis.

Total knee arthroplasty (TKR) using a medial capsular approach gives worse results in arthritic knees with valgus deformity than in those in varus, usually because of swelling, poor wound healing and stiffness, instability, recurrent valgus deformity and poor patellar tracking. A technique for replacement TKR of valgus knees using a lateral capsular approach was described several years ago, but was not routinely adopted because of the difficulties with and complexity of the procedure which included deliberate elevation of the tibial tubercle. In order to avoid this we have modified and simplified the procedure. Our preliminary results suggest that this lateral approach is safe and may give a better outcome than that through the medial capsule for the replacement of valgus knees.

Screening for congenital dislocation of the hip by physiotherapists. Results of a ten-year study.

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.

Treatment of delayed- and non-union of fractures using pulsed electromagnetic fields.

A prospective series of 32 consecutive patients, with 33 long-bone fractures suffering from delayed- or non-union were treated by pulsed electromagnetic fields (PEMF) or by PEMF with surgery. The management regime for the PEMF treatment was simpler and less rigid than that reported by Bassett et al. and our stimulation waveform was also different. Nineteen fractures (100%) treated with surgery and PEMF united within nine months of the commencement of PEMF treatment. Fourteen fractures were treated with PEMF alone. Twelve (86%) united within ten months and two failed to unite. The results of this study suggest that the stimulating waveform is less critical than is claimed by Bassett et al. and that a simpler and easier management regime for PEMF treatment can be just as effective. Alternatively PEMF may have no effect on fracture healing.

Delayed median nerve injury due to retained glass fragments. A report of two cases.

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.

Entrapment neuropathy of the superficial peroneal nerve. A bilateral case.

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.

Ruptured femoral vein. A complication of the use of gentamicin beads in an infected excision arthroplasty of the hip.

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.

The winged scapula.

Twenty-five patients with 23 different types of winging of the scapula are described. A simple clinical and etiologic classification of the winged scapula is proposed based on the study of these patients in conjunction with a review of the literature. Winging of the scapula is either static or dynamic. Static winging is due to fixed deformity in the shoulder girdle, spine, or ribs. Dynamic winging is due to a neuromuscular disorder. The great variety of lesions that produce winging of the scapula may be classified anatomically into four types: Type I, nerve; Type II, muscle; Type III, bone; and Type IV, joint. Winging of the scapula is a surprisingly common physical sign, but because it is often asymptomatic it receives little attention. However, symptoms of pain, weakness, or cosmetic deformity may demand attention, and it is hoped that this classification will help in the diagnosis and assessment of these patients.

Traumatic dislocation of the hip in adolescence with separation of the capital epiphysis. Two case reports.

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.