Revision for recurrent dislocation of total hip replacement

Dislocation is one of the commonest complications of total hip arthroplasty with an incidence of between 0.5 and 9.2%. Despite this, little is known of the outcome of treatment strategies for dislocation. The aim of this study was to establish the optimal strategy for the operative management of recurrent dislocation following THA taking account of the surgical approach employed in the replacement that became unstable and the direction of the instability that followed.

We reviewed 70 patients who underwent revision surgery for recurrent dislocation after total hip arthroplasty (THA), 38 through the transgluteal (Hardinge) and 32 through the posterior approach.52 of these followed primary and 18 followed revision THA for reasons other than instability.We recorded the surgical approach, the direction of dislocation and the operative strategy employed for each case.

We achieved stability in 75% of patients who dislocated after primary and 50% after revision THA. 77% of dislocations performed initially through the transgluteal approach were anterior and 88% through the posterior approach were posterior. Following the transgluteal approach, we stabilised anterior dislocation in 54% of cases. Following the posterior approach we stabilised posterior dislocation in 79%. The most successful operative strategy overall was cup augmentation which conferred stability in 90% of cases.

Instability after primary total hip replacement is easier to treat (75% chance of success) than after revision total hip replacement (50% chance of success). Although previous studies have shown that the posterior approach has a slightly higher risk of dislocation, this study has shown that achieving stability after a posterior dislocation is more likely than after an anterior dislocation. The outcome of revision for instability depends on the surgical approach used initially, and the direction of dislocation.