THE MANAGEMENT OF PERIPROSTHETIC ACETABULAR BONE LOSS WITH BURCH-SCHNEIDER ANTI-PROTRUSIO CAGE AND MASSIVE ALLOGRAFTS: MINIMUM 10-YEAR FOLLOW-UP RESULTS

Abstract

Introduction: The management of periprosthetic osteolysis is a challenging problem in revision hip arthroplasty. Filling acetabular bone defects with structural allografts resulted in early failure due to resorption of the graft. The application in combination with reinforcement rings should promote bone incorporation as a result of reduced mechanical stresses. This study evaluates the long-term results in the treatment of acetabular deficiencies using bulk allografts supported with a Burch-Schneider Anti-Protrusio Cage (APC).

Materials and Methods: From January 1992 to December 1995, 69 consecutive patients underwent revision surgery following periprosthetic osteolysis and aseptic loosening of the cup. Acetabular bone loss included IIIA and IIIB types according to Paproski classification. 12 patients died for unrelated causes with a well-functioning total hip arthroplasty in situ. 3 cases were lost at follow-up. The study group consisted of 56 hips in 54 patients. There were 11 males and 43 females, aged from 33 to 84 years (medium 65). Average follow-up was 11.7 years, ranging from 10 to 14.4. Surgical procedure included filling acetabular bone defects with bulk allografts supported with a Burch-Schneider APC which was fixed with screws to the iliac bone. A poly-ethylene cup was finally cemented into the metal cage. Deambulation was allowed one week after surgery, but weightbearing was delayed two months. Clinical evaluation was determined using Harris hip score (HHS). The stability of the acetabular implant was assessed according to Gill criteria. The progression of the bone graft was evaluated using Gross grading.

Results: 2 patients developed deep infection that was treated by resection-arthroplasty. Aseptic loosening of acetabular cage following an extensive resorption of bone graft was observed in 6 cases and 3 of them underwent rerevision. X-ray signs of graft incorporation occurred in 48 hips. Average HHS values of 30 (range, 11 to 81) and 75 (range, 28 to 100) points were assessed respectively in the preoperative time and at follow-up.

Discussion and Conclusions: In severe acetabular bone deficiencies the application of reinforcement rings in combination with massive allografts has been advocated in order to prevent bone graft resorption and cup loosening. Burch-Schneider Anti-Protrusio Cage is able to protect the graft spanning bone defects and promoting augmentation of periprosthetic bone stock. With an aseptic failure rate of 8.9% and a total survival rate of 85.7% at an average of 11.7 years, the use of APC and structural allograft proved out to be an effective procedure in the long-term reconstructive treatment of extensive loss of acetabular bone stock.