[Acetabulum reinforcement ring with allograft bone for reconstructing acetabular defects in hip revision].

OBJECTIVE: To evaluate the effectiveness of acetabulum reinforcement ring (Cage) with allograft bone for reconstructing acetabular defects in hip revision.

METHODS: Between February 2006 and August 2010, 14 patients (14 hips) with serious acetabular bone defects after total hip arthroplasty underwent acetabular reconstruction by using Cage with allograft bone. There were 6 males and 8 females with a mean age of 59.2 years (range, 45-76 years). The mean time between first replacement and revision was 7.2 years (range, 5-12 years). The revision causes included infection in 8 cases, osteolysis and aseptic loosening in 6 cases. The hip function Harris score was 37.7 +/- 5.3. According to America Association of Orthopedic Surgeon (AAOS) standard, the acetabular defect was classified as type III in 8 cases and as type IV in 6 cases.

RESULTS: All incisions healed by first intention, and no complication occurred. The patients were followed up 14-62 months (mean, 44 months). The pain was relieved or disappeared. At last follow-up, the Harris score was 89.7 +/- 3.2, showing significant difference when compared with preoperative score (t = -44.40, P = 0.04). No loosening of the acetabular component or osteolysis was found in 14 hips. No absorption or collapse of the allograft was observed in all patients.

CONCLUSION: Cage with allograft bone is a useful method of reconstructing acetabular bone defects in hip revision. Further follow-up is needed to assess the long-term effectiveness.