We report the early failure, at a mean of 37 months, of 17 femoral prostheses due to aseptic loosening at the cement-bone interface. In every case the prosthesis had been manufactured with a surface coating designed to enhance the strength of the cement-prosthesis interface. It is postulated that improving the bond at the cement-prosthesis interface may transfer increased stress to the cement-bone interface and cause early failure at that interface

Aims

Knee arthroplasty surgery is a highly effective treatment for arthritis and disorders of the knee. There are a wide variety of implant brands and types of knee arthroplasty available to surgeons. As a result of a number of highly publicized failures, arthroplasty surgery is highly regulated in the UK and many other countries through national registries, introduced to monitor implant performance, surgeons, and hospitals. With time, the options available within many brand portfolios have grown, with alternative tibial or femoral components, tibial insert materials, or shapes and patella resurfacings. In this study we have investigated the effect of the expansion of implant brand portfolios and where there may be a lack of transparency around a brand name. We also aimed to establish the potential numbers of compatible implant construct combinations.

Aims

Total knee arthroplasty is an established treatment for knee osteoarthritis with excellent long-term results, but there remains controversy about the role of uncemented prostheses. We present the long-term results of a randomized trial comparing an uncemented tantalum metal tibial component with a conventional cemented component of the same implant design.

Aims

This study explores data quality in operation type and fracture classification recorded as part of a large research study and a national audit with an independent review.

Aims

The aim of this study was to determine the stability of a new short femoral stem compared with a conventional femoral stem in patients undergoing cementless total hip arthroplasty (THA), in a prospective randomized controlled trial using radiostereometric analysis (RSA).

Aims

Instability remains a challenging problem in both primary and revision total hip arthroplasty (THA). Dual mobility components confer increased stability, but there are concerns about the unique complications associated with these designs, as well as the long-term survivorship.

Aims

The Intraosseous Transcutaneous Amputation Prosthesis (ITAP) may improve quality of life for amputees by avoiding soft-tissue complications associated with socket prostheses and by improving sensory feedback and function. It relies on the formation of a seal between the soft tissues and the implant and currently has a flange with drilled holes to promote dermal attachment. Despite this, infection remains a significant risk. This study explored alternative strategies to enhance soft-tissue integration.

There is increasing global awareness of adverse reactions to metal debris and elevated serum metal ion concentrations following the use of second generation metal-on-metal total hip arthroplasties. The high incidence of these complications can be largely attributed to corrosion at the head-neck interface. Severe corrosion of the taper is identified most commonly in association with larger diameter femoral heads. However, there is emerging evidence of varying levels of corrosion observed in retrieved components with smaller diameter femoral heads. This same mechanism of galvanic and mechanically-assisted crevice corrosion has been observed in metal-on-polyethylene and ceramic components, suggesting an inherent biomechanical problem with current designs of the head-neck interface.

We provide a review of the fundamental questions and answers clinicians and researchers must understand regarding corrosion of the taper, and its relevance to current orthopaedic practice.

Cite this article: Bone Joint J 2016;98-B:579–84.

Aim

Until now, there has been no consensus as to whether stemmed acetabular components are appropriate for use in patients undergoing revision total hip arthroplasty (THA) who have major acetabular defects or pelvic discontinuity. We wished to address this deficiency in the literature.

Metal-on-metal hip arthroplasty gained significant favor in the first decade of the millennium. However, the past several years have seen increasing reports of failure, pseudotumor and other adverse reactions. This study presents the results of a single center’s 15-year experience with metal-on-metal total hip arthroplasty as strong evidence that metal-on-metal is going, going, gone.

We present a series of 35 patients (19 men and 16 women) with a mean age of 64 years (36.7 to 75.9), who underwent total hip replacement using the ESKA dual-modular short stem with metal on-polyethylene bearing surfaces. This implant has a modular neck section in addition to the modular head. Of these patients, three presented with increasing post-operative pain due to pseudotumour formation that resulted from corrosion at the modular neck-stem junction. These patients underwent further surgery and aseptic lymphocytic vaculitis associated lesions were demonstrated on histological analysis.

Retrieval analysis of two modular necks showed corrosion at the neck-stem taper. Blood cobalt and chromium levels were measured at a mean of nine months (3 to 28) following surgery. These were compared with the levels in seven control patients (three men and four women) with a mean age of 53.4 years (32.1 to 64.1), who had an identical prosthesis and articulation but with a prosthesis that had no modularity at neck-stem junction. The mean blood levels of cobalt in the study group were raised at 50.75 nmol/l (5 to 145) compared with 5.6 nmol/l (2 to 13) in control patients.

Corrosion at neck-stem tapers has been identified as an important source of metal ion release and pseudotumour formation requiring revision surgery. Finite element modelling of the dual modular stem demonstrated high stresses at the modular stem-neck junction. Dual modular cobalt-chrome hip prostheses should be used with caution due to these concerns.

We present the outcomes in 38 consecutive patients who had total ankle replacement using the Ankle Evolution System with a minimum follow-up of four years. Pain and function were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) score and regular standardised anteroposterior and lateral weight-bearing radiographs were obtained. Patient satisfaction and complications were recorded and the survival of the implants was demonstrated by the Kaplan-Meier method.

The mean follow-up was for 57.8 months (48 to 80). The cumulative survival rate at six years was 94.7% (95% confidence interval 80.3 to 98.7). The mean total AOFAS score was 88.1 (53 to 100). The mean score for pain was 35.8 (20 to 40). Ten patients presented with edge-loading of whom nine had corrective surgery. Two ankles were revised, one to an arthrodesis and the other to replace the tibial component. Nine patients showed radiological evidence of osteolysis. They had minimal non-progressive symptoms and further surgery was not undertaken. Nevertheless, the concerns about osteolysis led to the implant being withdrawn by the manufacturer.

The medium-term results of the ankle evolution system ankle replacement are satisfactory with high patient satisfaction, but the rate of osteolysis is of some concern. The long-term benefit of this procedure has yet to be determined.

Pelvic discontinuity represents a rare but challenging problem for orthopaedic surgeons. It is most commonly encountered during revision total hip replacement, but can also result from an iatrogentic acetabular fracture during hip replacement. The general principles in management of pelvic discontinuity include restoration of the continuity between the ilium and the ischium, typically with some form of plating. Bone grafting is frequently required to restore pelvic bone stock. The acetabular component is then impacted, typically using an uncemented, trabecular metal component. Fixation with multiple supplemental screws is performed. For larger defects, a so-called ‘cup–cage’ reconstruction, or a custom triflange implant may be required. Pre-operative CT scanning can greatly assist in planning and evaluating the remaining bone stock available for bony ingrowth. Generally, good results have been reported for constructs that restore stability to the pelvis and allow some form of biologic ingrowth.

Cite this article: Bone Joint J 2013;95-B, Supple A:109–13.

We describe a cohort of patients with a high rate of mid-term failure following Kinemax Plus total knee replacement inserted between 1998 and 2001. This implant has been recorded as having a survival rate of 96% at ten years. However, in our series the survival rate was 75% at nine years. This was also significantly lower than that of subsequent consecutive series of PFC Sigma knee replacements performed by the same surgeon. No differences were found in the clinical and radiological parameters between the two groups. At revision the most striking finding was polyethylene wear. An independent analysis of the polyethylene components was therefore undertaken. Scanning electron microscopy revealed type 2 fusion defects in the ultra-high molecular weight polyethylene (UHMWPE), which indicated incomplete boundary fusion. Other abnormalities consistent with weak UHMWPE particle interface strength were present in both the explanted inserts and in unused inserts from the same period.

We consider that these type 2 fusion defects are the cause of the early failure of the Kinemax implants. This may represent a manufacturing defect resulting in a form of programmed polyethylene failure.

Bisphosphonates reduce peri-prosthetic bone loss in the short term after total hip replacement but the mid- and longer term effects are not known. The aims of this randomised trial were to examine the effect of a single dose of 90 mg of pamidronate on the clinical and radiological outcome and peri-prosthetic bone mineral density in 50 patients (56 hips) over a five-year period, following total hip replacement.

At five years, 37 patients (42 hips) returned for assessment. The Harris hip scores were similar in the pamidronate and placebo groups throughout the study. Also at five years, four patients, two from each group had osteolytic lesions on plain radiography. These were located around the acetabular component in three patients and in the femoral calcar in one. The femoral and acetabular peri-prosthetic bone mineral density in the pamidronate group and the control group was similar at five years.

Pamidronate given as a single post-operative dose does not appear to influence the clinical outcome or prevent the development of osteolytic lesions at five years after total hip replacement.