Introduction

To evaluate the clinical success and hip pain and function of patients with infected hip replacement treated by two-stage exchange using a temporary implant with high dose vancomycin added to the antibiotic cement at the first stage revision.

The purpose of this paper is to review the early results of Prostalac system under licence from Therapeutic Goods Administration for Professor Howie in the management of two stage exchange hip arthroplasty for infection (restricted to Royal Adelaide Hospital) and the addition of vancomycin and teicoplanin powder to tobramycin cement without additional tobramycin.

Thirteen patients were treated for an infected THR with the Prostalac system. Preoperative and intra-operative cultures were taken to identify the infective organisms. Vancomycin 3 gm was added to the Prostalac cement mantle per 40 gm packet of antibiotic bone cement containing tobramycin 1 gm. Teicoplanin 2.4 gm was used in one case where the patient had a known vancomycin allergy. Postoperatively patients underwent six weeks of IV antibiotics followed by four to six weeks of oral.

A short term successful clinical outcome was determined by implantation of a total hip prosthesis at the time of second stage operation and no reoperations resulting from recurrent infection and off antibiotics for â□¥ 6 months with normal clinical and CRP lab values.

Thirteen patients received the Prostalac system. No patient was lost to follow-up. Nine have progressed to second stage revision, eight of which had femoral impaction grafting. Two deaths occurred not attributed to the Prostalac system. Three superficial wound infections and two required washout and debridement. One Prostalac stem subsidence. There has been no recurrence of deep joint infection. Retention of the second stage prosthesis has been 100% at 17 months.

The PROSTALAC system with the addition of vancomycin or teicoplanin to the tobramycin antibiotic cement has encouraging short-term results for treatment of deep joint infection. Complication rate has been well within the range reported in literature. Successful early outcomes are encouraging with all patients in the Prostalac study having retained their permanent hip prosthesis following second stage surgery.

This study aimed to compare the early clinical results and stem subsidence between three consecutive series of revision hip replacement cases with femoral impaction bone grafting to evaluate the effects of developments in technique. In the original series 1 (n=23), bone graft was irradiated at 25kG. I n series 2 (n=12) non-irradiated double washed graft and long stems were used as required.

In series 3 (n=21) modular tamps were used. Sensitive radiographic analysis techniques, EBRA and RSA, were used to measure stem subsidence. Major stem re-revision was required in five hips in series one, one hip in series two and no hips in series three. Two periprosthetic fractures occurred in series one. There was a statistically significant reduction in stem subsidence at the cement-bone interface at 12 months between series one and series two and three (p<0.05). In series three there was negligible stem subsidence at the cement-bone interface.

Technique developments in femoral impaction grafting, including the use of modular tamps designed to simply the procedure, yields excellent early clinical and radiographic results. Using RSA, we have shown that the fixation of the stems in bone is comparable to that achieved in primary hip replacement.