LONG-TERM RESULTS OF CEMENTLESS FULLY HAC COATED ACETABULAR CUPS IN PRIMAY ARTHROPLASTY

Abstract

Introduction: We aim to report the clinical and radiological outcome of consecutive primary hip arthroplasties using the JRI-Furlong Hydroxyapatite ceramic (HAC) coated acetabular components.

Methods: We reviewed 412 consecutive cementless primary THA using fully coated acetabular shell in 392 patients, with a minimum 12-year follow-up to 18 years, performed at two institutions between 1986 and 1994. Twenty (22 THA) were lost prior to 12-year follow-up, leaving 372 patients (390 THA) available for study. Fully HAC coated stems were used in all patients. The clinical outcome was measured using Harris, Charnley and Oxford hip scores. Quality of life using EuroQol EQ-5D. Radiographs were systematically analysed for implant position, loosening, migration, osteolysis. Polythene wear was digitally measured. The radiographic stability of the acetabular component was determined by Enghs criteria

Results: The mean age was 74.4 yrs. Dislocation occurred in 10 patients (3 recurrent). Re operations were performed in 9 patients (1.9%). Four acetabular revisions were performed for aseptic loosening. Other re-operations were for infection (3), periprosthetic fractures (1), cup malposition (1), revision of worn liner (3). The mean Harris and Oxford scores were 87 (78–97) and 19.1 (12–33) respectively. The Charnley score was 5.6 (5–6) for pain, 5.2 (4–6) for movement and 5.3 (4–6) for mobility. Migration of acetabular component was seen in 4 hips. Acetabular radiolucencies were present in 54 hips (9.7%). The mean linear polythene wear was 0.06mm/year. Mean inclination was 48.4deg(38–65). Radiolucencies were present around 37 (6.6%) stems. Mean EQ–5D description scores and health thermometer scores were 0.81 (0.71–0.89) and 86 (64–95). With an end point of definite or probable loosening, the probability of survival at 12 years was 96.1% for acetabular Overall survival at 12 years with removal or repeat revision of either component for any reason as the end point was 94.2%.

Discusssion and conclusion: The results of this study support the continued use of a fully coated prosthesis and documents the durability of the HAC coated components. In our clinical experience, the Furlong prosthesis revealed encouraging radiographic stability over a long term period.