Clinical and radiographic evaluation of cemented socket fixation concomitant to acetabular bone grafting fixed with absorbable hydroxyapatite-poly-l-lactide composite screws.

BACKGROUND

The durability of uncalcined and unsintered hydroxyapatite-poly-l-lactide composite screws is unclear when used for the fixation of acetabular bone graft in total hip arthroplasty under full-weight conditions. We have used this type of screw for the fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty since 2003. Hence, we conducted a follow-up study to assess the safety and efficacy of these screws when used for cemented socket fixation.

METHODS

In this study, 98 patients (106 cases) who underwent fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty using hydroxyapatite-poly-l-lactide composite screws were followed up for over 5 years and evaluated clinically and radiographically. The patient population comprised 10 men and 88 women with a mean age of 60.3 years (range, 41-81 years) at the time of surgery. The original diagnosis for primary total hip arthroplasty was secondary osteoarthritis in 97 cases and high hip dislocation in nine cases.

RESULTS

The mean follow-up period was 7.6 years (range, 5-11 years). No patient in this series required revision surgery, and no radiographical loosening occurred during the follow-up period. The mean Japanese Orthopaedic Association score improved from 48 (range, 7-73) preoperatively to 87 (range, 50-100) at the final follow-up. Radiographically bone graft consolidation was confirmed in all cases, and no apparent osteolysis around the cemented socket or composite screws was detected. Kaplan-Meier survival analyses with socket revision surgery for any reason, socket loosening, and appearance of a radiolucent line >1 mm in any zone as the endpoints yielded survival rates of 100%, 100%, and 86.8% at 5 years, and 100%, 100%, and 81.0% at 10 years, respectively.

CONCLUSION

This absorbable screw seems to have no negative effects on the mid-term clinical results of cemented socket fixation.