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.

The Metasul metal-on-metal articulation in primary total hip replacement: clinical and radiological results at ten years.

We report the clinical and radiological outcome at ten years of 104 primary total hip replacements (100 patients) using the Metasul metal-on-metal bearing. Of these, 52 had a cemented Stuehmer-Weber polyethylene acetabular component with a Metasul bearing and 52 had an uncemented Allofit acetabular component with a Metasul liner. A total of 15 patients (16 hips) died before their follow-up at ten years and three were lost to follow-up. The study group therefore comprised 82 patients (85 hips). The mean Oxford score at ten years was 20.7 (12 to 42). Six of 85 hips required revision surgery. One was performed because of infection, one for aseptic loosening of the acetabular component and four because of unexplained pain. Histological examination showed an aseptic lymphocytic vasculitis associated lesion-type tissue response in two of these. Continued follow-up is advocated in order to monitor the long-term performance of the Metasul bearing and tissue responses to metal debris.

Fast-track assessment clinic: selection of patients for a one-stop hip assessment clinic.

INTRODUCTION: The fast-track assessment clinic (FTAC) is a process to select patients who are very likely to require primary total hip replacement. Selected patients can then be seen in a one-off clinic reducing the number of hospital visits, cost to primary care trusts and delay between referral and treatment. PATIENTS AND METHODS: Fifty patients on the waiting list for hip replacement were analysed to see if there were common parameters that led to their inclusion. From these data, fast-track selection criteria (FTSCs) were generated. These FTSCs were used to make a dual comparison of outcomes between 52 patients seen in a traditional clinic. Finally, a pilot study was conducted in which patients fulfilling FTSCs were seen in a designated clinic. RESULTS: An Oxford hip score (OHS) of 34 and above combined with severe loss of joint space, severe marginal osteophytes, or both was common to most patients on the waiting list (84%). FTSCs correctly predicted the outcome of the orthopaedic clinic in 38 patients out of a total of 52. During the pilot stage, positive FTSCs were shown to have a positive predictive value of 92% for joint replacement being carried out and a negative predictive value of 46%. CONCLUSIONS: An OHS of 34 or above combined with complete loss of joint space and/or severe marginal osteophyte formation can be used to select patients who are very likely to need total hip replacement. These patients can be seen in a clinic that combines assessment of surgical indication with medical fitness for surgery.

Birmingham hip resurfacing: is acetabular bone conserved?

Hip resurfacing is a bone-conserving procedure with respect to proximal femoral resection, but there is debate in the literature as to whether the same holds true for the acetabulum. We have investigated whether the Birmingham hip resurfacing conserves acetabular bone. Between 1998 and 2005, 500 Birmingham hip resurfacings were performed by two surgeons. Between 1996 and 2005 they undertook 700 primary hip replacements, with an uncemented acetabular component. These patients formed the clinical material to compare acetabular component sizing. The Birmingham hip resurfacing group comprised 350 hips in men and 150 hips in women. The uncemented total hip replacement group comprised 236 hips in men and 464 hips in women. Age- and gender-matched analysis of a cohort of patients for the sizes of the acetabular components required for the two types of replacement was also undertaken. Additionally, an analysis of the sizes of the components used by each surgeon was performed. For age-matched women, the mean outside diameter of the Birmingham hip resurfacing acetabular components was 2.03 mm less than that of the acetabular components in the uncemented total hip replacements (p < 0.0001). In similarly matched men there was no significant difference (p = 0.77). A significant difference was also found between the size of acetabular components used by the two surgeons for Birmingham hip resurfacing for both men (p = 0.0015) and women (p = 0.001). In contrast, no significant difference was found between the size of acetabular components used by the two surgeons for uncemented total hip replacement in either men or women (p = 0.06 and p = 0.14, respectively). This suggests that variations in acetabular preparation also influence acetabular component size in hip resurfacing.

Early results for treatment of three- and four-part fractures of the proximal humerus using the PHILOS plate system.

Secure fixation of displaced proximal fractures of the humerus is a challenging problem. A total of 32 patients with acutely displaced three- or four-part proximal fractures of the humerus were treated by open reduction and internal fixation using the proximal humeral internal locking system (PHILOS) plate. There were 23 women and nine men with a mean age of 59.9 years (18 to 87). Data were collected prospectively and the outcomes were assessed using the Constant score. The mean follow-up was for 11 months (3 to 24). In 31 patients (97%) the fracture united clinically and radiologically at a mean of 10 weeks (8 to 24). The mean Constant score at final review was 66.5 (30 to 92). There was no significant difference in outcome when comparing patients aged more than 60 years (18 patients) with those aged less than 60 years (14 patients) (t-test, p = 0.8443). There was one case each of nonunion, malunion and a broken screw in the elderly population. This plate provides an alternative method of fixation for fractures of the proximal humerus. It provides a stable fixation in young patients with good-quality bone sufficient to permit early mobilisation. Failure of the screws to maintain fixation in the elderly remains a problem.

Intra-articular pull out of an interference screw after anterior cruciate ligament reconstruction.

We report a rare case of late femoral interference screw migration in the posterior compartment of the knee after anterior cruciate ligament reconstruction. The graft was intact with no signs of damage. The screw was successfully removed through the posteromedial portal site and the patient regained full function of the knee.

Intra-articular pull out of an interference screw after anterior cruciate ligament reconstruction.

We report a rare case of late femoral interference screw migration in the posterior compartment of the knee after anterior cruciate ligament reconstruction. The graft was intact with no signs of damage. The screw was successfully removed through the posteromedial portal site and the patient regained full function of the knee.