Aims

The burden of revision total hip arthroplasty (rTHA) continues to grow. The surgery is complex and associated with significant costs. Regional rTHA networks have been proposed to improve outcomes and to reduce re-revisions, and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for a rTHA service, and to assess the financial impact of case complexity at a tertiary referral centre within the NHS.

Aims: Dislocation is one of the commonest complications following total hip arthroplasty. A significant proportion of these patients go on to have recurrent dislocations. Many factors have been identified as contributing to the risk of dislocation but treatment of recurrent dislocation is challenging. The use of semicaptive acetabular components is a potential solution to the problem of recurrent dislocation but there are few studies into the efficacy of these implants.

Methods: Patients who underwent revision of their total hip arthroplasty to a semi-captive socket at the Lower Limb Arthroplasty Unit, Northern General Hospital, Sheffield between 2001 and March 2006 were studied. A proforma was designed and data was obtained from patients’ medical records. The number of dislocations both prior to revision to a semi-captive component and the following revision to a semi-captive acetabular component were recorded including the method of reduction Reasons for revision and the number and reasons for previous revisions were noted.

Results: Average time of follow up was 22 months (range 2 months – 5 years 1 month). Following revision of total hip arthroplasty to a semi-captive component, 78% suffered no further dislocations. Of those patients who went on to redislocate, three went on to have recurrent dislocations and all were reduced by closed reduction. One patient redislocated and underwent a second revision to a semi-captive acetabular component, which was successful and underwent no further dislocations.

Discussion. The results of this study show the use of semicaptive acetabular components in revision surgery for dislocation following total hip arthroplasty to be a highly effective solution to the problem of recurrent dislocation.

Introduction: Deep infection is a devastating complication following hip arthroplasty. In the early 1970’s Staphylococcus Aureus (SA) was believed to be the causative organism in most cases and Coagulase Negative Staphylococccus (CNS) was widely regarded as a contaminant. It subsequently became recognised that the majority of infections are caused by CNS rather than SA, probably due to the use of peri-operative antimicrobial agents and laminar air flow in theatre.

Aims: The aim of this study was to look at the causative organisms in patients with an infected total hip replacement to see if the pattern of infection has changed with time.

Methods: Between February 1999 and November 2004, 95 patients underwent 1^st stage revision surgery at the Northern General Hospital for definite infection following total hip replacement. At least 5 tissue samples were taken at the time of surgery prior to antibiotic administration. Infection was confirmed when at least 3 of the samples were positive on microbiological culture. We retrospectively reviewed the records of these patients and identified the causative organisms.

Results: The 95 patients were infected with 130 different organisms. Of these 32% were SA including MRSA (7.2%), 27% CNS, 13.6% Enterococcus, 4.8% pseudomonas and 3.2% Streptococcci. 29% of patients had polymicrobial infection.

Discussion: Data published in the literature as well as historical data from our unit suggest that CNS is by far the most common organism causing prosthetic hip joint infection. Our results however, show a recent decrease in the proportion of CNS and an increase in SA and polymicrobial infection.

Purpose: The role of hip aspiration as a preoperative investigation for the painful hip remains controversial. Since 1999, we have performed hip aspiration under local anaesthetics in the X-ray department. This paper reviews our experience with this technique.

Results: Hip aspirations were carried out subsequently on 182 patients from November 1999 to November 2002. Out of 68 patients that underwent revision hip surgery, 63 were included in the study. Three of the five patients excluded had received antibiotics at induction prior to obtaining the operative samples and two did not have any operative samples taken at the time of surgery. Fifteen (23.8%) of the 63 hips were found to be infected based on operative tissue cultures. The sensitivity and specificity of the test were 80% and 87.5%, respectively. Positive and negative predictive values were 66.6% and 93.3% respectively and the accuracy was 85.7%.

Conclusion: Hip aspiration in the Radiology department is a simple, cost effective and reliable preoperative test when used selectively. When used in combination with other laboratory and radiological investigation it can act as an important preoperative investigation in the diagnosis of sepsis. There is an added advantage of identifying the microorganism along with its antibiotic sensitivities. This can guide clinicians in choosing the correct antibiotic for the cement and also for the postoperative antibiotic therapy.

The Huckstep ( Bbraun Medical) interlocking hip prosthesis has been used in the Sheffield Lower Limb Arthroplasty Unit in cases of complex primary and revision hip arthroplasty since 1996. We reviewed the outcomes in cases performed prior to October 2001.

Eighty cases were identified. Of these, eight died within one year of surgery, four of which were in the peri operative period. A further thirteen were lost to follow up in the first year due to medical deterioration, move from area or refusal to attend. The remaining 57 patients had a mean time to follow up of 34 months (12–81m).

As a primary prosthesis the Huckstep was used to allow corrective osteotomy. In revision cases it was employed to bypass periprosthetic fractures and fragile proximal femoral bone, in cases requiring extended trochanteric osteotomy to facilitate cement removal, and to enable use of bulk proximal femoral allograft. The use of the Huckstep was planned pre operatively in 67 cases and as a salvage option in 13.The design of the implant allowed a stable construct without the need for bone cement which could interpose and prevent bone healing or graft incorporation. It avoids problems incurred in pressurising cement or impaction grafting against fragile bone.

Complications included infection requiring further surgery (5), dislocation (5), periprosthetic fracture (2), screw breakage (4), and mechanical failure (2). Eleven patients required further revision surgery. The apparently high complication rate reflects the complex nature of the surgery and the high degree of co morbidity in the elderly patient group.

In conclusion, we have found the Huckstep hip prosthesis to be a useful option in cases of complex hip surgery. Whilst the long term outcome is as yet unknown, our short term results show it to have allowed healing of fractures, osteotomy sites and cortical defects, allograft incorporation and replenishing of bone stock, hence facilitating further arthroplasty surgery.

The incidence of infection after primary arthroplasty is low. However, with the increasing number of arthroplasties being performed the prevalence of infection is increasing. The pattern of infecting organisms following total joint arthroplasty has changed and gentamicin resistant organisms are becoming increasingly common. Vancomycin added to bone a cement carrier can, with adequate surgical debridement be very effective in the eradication of established resistant infection. We report the results of its use in 33 patients with 26 infected hip and 7 infected knee arthroplasies. 32 patients remain clinically and radiologically free of infection after a mean follow-up of 67 months. There was one recurrence of infection and there were three positive second stage cultures of uncertain significance. Vancomycin is potentially a very useful tool in the management of deep infection following arthroplasty surgery.