Aims

Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD.

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.