Dislocation of primary THA done through a posterolateral approach in the elderly

We assess the rate of dislocation of total hip arthroplasty (THA) through a posterolateral approach in elderly patients and determine if this complication can be minimized. We retrospectively reviewed 150 THAs done between 1992 and 2002, through a posterolateral approach in patients 80 years and older. A hybrid THA was done in 46% of patients and both components were cemented in 54% of patients. A 28-mm head was used in 83% of the patients and a 32-mm head was used in 17% of patients. An elevated liner, with the elevation placed posteriorly, was used in 38% of hybrid cases. Starting in mid-1998, the posterior capsule was preserved and repaired at the time of wound closure (n = 77, 51%). Dislocation occurred in eight hips (five recurrent) at an average time to dislocation of 26.9 months (range, 1-79 months). No dislocations occurred when using a 32-mm head or a 28-mm head with a lipped liner in association with repair of the posterior capsule. Statistical regression analysis indicated that capsular repair was the single most important predictive factor for dislocation. When using the posterolateral approach for THA in patients older than 80 years, we suggest using a 32-mm head in combination with posterior capsular repair to reduce the incidence of dislocation.