A Minimum Ten Years of Follow-Up of Alumina Head on Delta Liner Total Hip Arthroplasty.

BACKGROUND: In the early days when delta ceramics were developed, there was a period of using delta ceramic liner and alumina ceramic head. Therefore, the purpose of this study is to investigate the clinical and radiological outcomes of total hip arthroplasty using delta ceramic liner on alumina ceramic head after a minimum of 10 years of follow-up and to evaluate problems of early delta ceramic liner.

METHODS: Alumina on delta cementless total hip arthroplasty was performed in 92 hips (85 patients) from August 2005 to March 2007 at our hospital. Bilateral total hip arthroplasty were performed in 7 patients, 30 patients on the left side and 48 patients on the right side. Preoperative diagnosis was osteonecrosis of the femoral head in 34 hips (37%), degenerative arthritis in 31 hips (33.7%), femur neck fracture in 21 hips (22.8%), and rheumatoid arthritis in 6 hips (6.5%). All surgeries were carried out with anterolateral approach. For the clinical evaluation, Harris hip score (HHS), pain, and range of motion were assessed. Radiographs were reviewed by the authors to search for any signs of osteolysis, loosening of implants, and heterotopic ossification.

RESULTS: HHS was compared between preoperative and final follow-ups. The mean HHS improved from preoperative 58.3 points (range 27-76) to 92.7 points (range 78-98) on the final follow-up (P = .02). The mean range of hip motion at the final follow-up was flexion 116.9°, adduction 23.8°, abduction 34.6°, internal rotation 16.3°, and external rotation 39.2°. As for the postoperative pain, 1 patient complained of inguinal pain and 4 patients complained of thigh pain. Because of trauma, 3 cases of dislocation were observed in all cases. There are 3 cases with dislocation and 2 cases were treated with conservative treatment without recurrence, but 1 case was required for surgical treatment due to eccentric rim wear of delta liner. The aseptic loosening of acetabular cup and femoral stem was each 1 hip.

CONCLUSION: Alumina head-on-delta liner cementless THA, using a large femoral head 32-36 mm in diameter, demonstrated satisfactory clinical and radiological results in the minimum 10 years of follow-up. Eccentric rim wear can occur even in delta ceramic liners that are known to have high strength, and this can lead to dislocation which can, in turn, increase the possibility of linear fracture.