ACETABULAR REINFORCEMENT RING AND STRUCTURAL ALLOGRAFT FOR RECONSTRUCTION OF SEVERE ACETABULAR BONE LOSS IN REVISION TOTAL HIP ARTHROPLASTY: 23 CASES REPORTED

Abstract

Introduction: Treatment of acetabular defects can be difficult, especially in case of roof destruction. Since 9 years, we use a variant of Paprosky’s technique which consists in rebuilding the roof by structural allograft and acetabular reinforcement ring. The purpose of this study is to present this technique and the follow up results.

Patients: This retrospective study concerns 21 patients (23 hips) with severe acetabular bone loss (8 cases of stage 2 and 15 cases of stage 3 of Paprosky): 4 septical and 19 aseptical loosening. Between 1998 and 2005, all patients were operated with the same surgical technique using an allogeneic structural allograft (femoral head or distal femur) and an acetabular reinforcement ring (20 of KERBOULL, 3 of GANZ) associated with a cemented PE cup.

Method: Review included a clinical and X-ray evaluation (analysis of the refocusing of the hip, the positioning and the stability of implants and the graft incorporation).

Results: Mean duration of follow-up is 3,5 years [1–8,3]. Preoperative PMA score rised from 6,6 [0–12] to 15,8 [12–18] in postoperative. There was no peroperative complication. After surgery, 2 cases of early hip dislocation required PE block; 2 cases of sepsis were treated, one by washing and one by a surgical revision. In 60% of cases, immediate total weight bearing was allowed.

The immediate postoperative X-rays showed that the rotation center of the hip was 5,2 mm [0–10] far from the ideal rotation center (26% of cases: 0 mm) and the PE cup was implanted with a lateral inclination of 42,5° [30–55]. In postoperative X-ray follow up, one case of acetabular aseptic loosening was found which didn’t need hip revision. In all other cases no modification of implants position neither of hip rotation center was noted. In 79% of cases, we had total graft incorporation; in 17% of cases, an non evolutive radiolucent area between graft and bone and in 4% of cases (loosening) a graft migration.

Conclusion: The use of a structural allograft combined with acetabular reinforcement ring allows hip reconstruction in severe acetabular bone loss with good medium term results.