Femoral head diameter affects the revision rate in total hip arthroplasty: an analysis of 1,720 hip replacements with 9-21 years of follow-up.

BACKGROUND

In a previous study concerning 1,660 ScanHip THAs that were followed for up to 12 years, the cumulative revision rate was not found to be dependent on whether a 22-mm or a 32-mm head size had been used. We have re-examined these patients to see whether a longer follow-up time (9-21 years) would disclose an effect of head size on the revision rate.

PATIENTS AND METHODS

We analyzed the cumulative revision rate for 1,720 Scan Hip arthroplasties with either 22-mm or 32-mm femoral heads. The patients were followed for 9-21 years.

RESULTS

Arthroplasties with 32-mm head had 2.8-times higher cumulative revision rate than those with a 22-mm head. Older age reduced the risk of revision while male sex increased the risk.

INTERPRETATION

We found that head size affects revision risk, but that even in a reasonably large material a long follow-up time is required to disclose the effects of head size--and thus wear--on survival.