S28 SURFACE REPLACEMENT OF THE HIP – A RADIOGRAPHIC ANALYSIS OF THE IMPLANT POSITION OBTAINED IN 72 HIPS WITH TWO DIFFERENT SURGICAL APPROACHES

Abstract

Different resurfacing implants offer different kinds of positioning instruments. As it is of outmost importance to position the components within rather narrow limits to diminish the risk of femoral notching or impingement we decided to measure the position achieved in 72 hips resurfaced with the Durom^® resurfacing hip and instruments.

There were 38 males and 27 females with 72 hips (7 bilateral). The indication was OA in 51 cases, RA in 12 and ON in 2. We compared 2 groups, 26 hips operated with an antero-lateral approach (A) and 46 with a postero-lateral approach (B).

The acetabular cup anteversion angle was 22±11° in group A and 15±9° in group B. The abduction angle was 38±9 ° in group A and 44±7° in group B. The acetabular gap was 2±1 mm, resp. 2±2 mm. The stem-shaft angle was 140±5° resp. 141±6°. Retroverted cups averaged 7±4°.

The difference between pre- and postoperative acetabular size was 3 mm in group A (mostly RA patients) and 5 mm in group B (mostly OA patients).

Conclusions: We have obtained a fairly good implant position. The only significant differences between the two groups were decreased acetabular cup abduction angle compared to the preoperative angle in the antero-lateral group, but increased angle in the postero-lateral group, and that less acetabular bone was removed in the antero-lateral group (patients with RA included) compared to the postero-lateral group.