Higher failure rate and stem migration of an uncemented femoral component in patients with femoral head osteonecrosis than in patients with osteoarthrosis

Background Several authors have found poorer outcome after hip replacement for osteonecrosis than after hip replacement for arthrosis. In a retrospective study we evaluated the performance of an uncemented femoral component in patients with osteonecrosis and arthrosis of the hip.

Patients and methods 31 patients operated for osteonecrosis, and 49 patients operated for osteoarthrosis were included. The median follow-up time was 6.1 (2–11) years for the patients with osteonecrosis, and 5.9 (4–8) for the arthrosis patients.

Results Migration analysis performed by the Einzel-Bild-Roentgen Analysis (EBRA) technique revealed a median stem migration of 1.5 (−8.8–0) mm in the patients with osteonecrosis, but only 0.6 (−2.8–0.7) mm in the patients with arthrosis (p < 0.001). Survivorship analysis with stem revision as endpoint for failure was 74% (95% CI: 55–94) in the osteonecrosis, and 98% (95% CI: 94–100) in the arthrosis group (p = 0.01).

Interpretation We suggest that the higher failure rate and stem migration of uncemented total hip replacement in the patients with osteonecrosis is a consequence of the disease. On the basis of these findings, we recommend close monitoring of the patients with osteonecrosis, which should include migration measurements.