[Analysis of the failure mechanisms of the revision hip arthroplasties]

To investigate the failure mechanisms of revision hip arthroplasties and evaluate the effects of surgical technique, prosthesis design and patient-related risk factors on different failure mechanisms.

A review of all revision hip arthroplasties from November 1995 to June 2008 identified 30 patients who underwent 30 revisions with 18 males and 12 females. The overall mean age for primary arthroplasties was 49 years (range 25-68 years) and 53 years (range 27-72 years) for index revision arthroplasties and the average interval between these two operations was 43.8 months (0-156 months). The failure mechanisms of index revision arthroplasties and primary arthroplasties were assessed and compared. Direct comparisons were made of data for the different age categories in terms of time to failures and reasons for failures.

Regarding revision or prosthesis removal as the end point of the study, the reasons for 30 revision arthroplasties were aseptic loosening in 22 hips (73.3%), infection in 4 hips (13.3%), periprosthetic fracture in 3 hips and instability in 1 hip (3.3%). The overall mean age for last arthroplasties or prosthesis removal was 58 years (range 38-77 years) with an average interval of 78.8 months (range 1-216 months) from previous revision arthroplasties. The mean time to failure for patients above 60 years of age was significantly shorter than patients below 60 years of age (P < 0.01).

The majority of failure mechanisms of revision hip arthroplasties are ineffective fixation of revisional implants and recurrence of local infection, which reveals the limitations to joint reconstruction philosophy and surgical technique.