Comparison of the uncemented Cone and the cemented Bimetric hip prosthesis in young patients with osteoarthritis: An RSA, clinical and radiographic study

Background There is no consensus as to whether uncemented or cemented femoral stems should be used in younger patients. We compared the uncemented Cone stem to the cemented Bimetric stem in young patients with osteoarthritis.

Patients and methods We randomized 45 relatively young patients (< 65 years old, mean age 54 years) with osteoarthritis to either an uncemented Cone stem or a cemented Bimetric stem. All patients were followed for 2 years. Outcome was assessed by the Merle d’Aubigné score, conventional radiography and repeated radio-stereometric analysis (RSA). We also followed 81 Cone stems for 8 (7–12) years with revision as endpoint.

Results The clinical outcome was excellent. No patient had postoperative thigh pain. The migration was small. The Bimetric stem was stable during the whole observation period, while the Cone stem subsided and rotated to retroversion during the first 3 months post-operatively, and then remained stable. In the follow-up study of 81 Cone stems, 1 stem was revised.

Interpretation We conclude that both the cemented Bimetric stem and the uncemented Cone stem are stable and give excellent clinical results after 2 years in relatively young patients with osteoarthritis. Although designed for CDH hips, the Cone stem appears to be suitable also for patients with osteoarthitis.