This study reports the mid-term results of a large-bearing hybrid metal-on-metal total hip replacement in 199 hips (185 patients) with a mean follow-up of 62 months (32 to 83).

Two patients died of unrelated causes and 13 were lost to follow-up. In all, 17 hips (8.5%) have undergone revision, and a further 14 are awaiting surgery. All revisions were symptomatic. Of the revision cases, 14 hips showed evidence of adverse reactions to metal debris. The patients revised or awaiting revision had significantly higher whole blood cobalt ion levels (p = 0.001), but no significant difference in acetabular component size or position compared with the unrevised patients. Wear analysis (n = 5) showed increased wear at the trunnion-head interface, normal levels of wear at the articulating surfaces and evidence of corrosion on the surface of the stem.

The cumulative survival rate, with revision for any reason, was 92.4% (95% confidence interval 87.4 to 95.4) at five years. Including those awaiting surgery, the revision rate would be 15.1% with a cumulative survival at five years of 89.6% (95% confidence interval 83.9 to 93.4).

This hybrid metal-on-metal total hip replacement series has shown an unacceptably high rate of failure, with evidence of high wear at the trunnion-head interface and passive corrosion of the stem surface. This raises concerns about the use of large heads on conventional 12/14 tapers.

Introduction and Aim: One of the suggested advantages of hip resurfacing arthroplasty is that it offers the possibility of a straightforward revision. As the femoral canal is not violated during the resurfacing procedure, it is postulated that the outcome of revision surgery should be equivalent to that of a primary hip arthroplasty. The purpose of this study was to investigate whether revision was as straightforward and as successful as has been suggested.

Method: 14 patients underwent revision surgery due to the failure of the femoral component of their Birmingham hip resurfacing. The femoral component was revised to a cemented Zimmer CPT stem, with a large modular metal head (MMT). The acetabular component was found to be well fixed and was left in situ. Radiographs were studied to review any change in offset or leg length. These patients were matched with a group who had undergone a hybrid total hip arthroplasty as a primary procedure, using the same bearing.

The Oxford and Harris Hip scores were used to measure outcome.

Results: In the revision group, there were 10 males and 4 females. The mean age was 56 (48–68). The mean time to revision was 11.6 months. The reasons for revisions were:

9 femoral neck fractures, 4 femoral neck resorption and 1 femoral component migration.

Post revision Oxford score =18 (12–25), HHS=92 (85.5–97.4).

Post primary Oxford score =18 (12–40), HHS=94.2 (86–97.4).

Comparison of the post-op radiographs demonstrated that offset was improved following revision. Leg length did not change significantly.

The mean follow-up was 2 years and there were no significant complications.

Discussion: Our results show that revision of the failed femoral component gives excellent results. The outcome was not significantly different to the primary THA group. Femoral offset was improved in total hip replacement compared to resurfacing.

We studied prospectively a consecutive series of 50 patients with chronic osteomyelitis. Patients were allocated to the following treatment groups: 1) wide resection, with a clearance margin of 5 mm or more; 2) marginal resection, with a clearance margin of less than 5 mm; and 3) intralesional biopsy, with debulking of the infected area. All patients had a course of antibiotics, intravenously for six weeks followed by orally for a further six weeks. No patients in group 1 had recurrence. In patients treated by marginal resection (group 2), 8 of 29 (28%) had recurrence. All patients who had debulking had a recurrence within one year of surgery. We performed a survival analysis to determine the time of the recurrence of infection. In group 2 there was a higher rate of recurrence in type-B hosts (p < 0.05); no type-A hosts had recurrence. This information is of use in planning surgery for chronic osteomyelitis.