Abstract
Introduction:
The incidence of heterotrophic ossification after primary total hip arthoplasty (THA) has been reported to be between 8 to 90%. The incidence is higher in lateral approach because of extensive muscular trauma associated with it. There exists limited data on the incidence of heterotrophic ossification after direct anterior approach (DAA) THA. The purpose of this study was to assess the incidence of heterotrophic ossification after THA via the direct anterior approach and the influence of surgical technique and chemoprophylaxis.
Method:
A consecutive series of four hundred two primary uncemented direct anterior approach total hip arthoplasties in 378 patients were reviewed for incidence of heterotrophic ossification. In the first 200 total hip arthoplasties an anterior capsulectomy (Group 1) was done for exposure while in the subsequent 202 total hip arthoplasties a capsulotomy (Group 2) followed by complete release of supero-lateral flap of from its attachement to the gluteus minimus muscle and trochanter was performed (Figure 1). Group 1 received warfarin for thromboprophylaxis; while aspirin (thromboprophylaxis) and celecoxib (pain) was used in group 2. Heterotrophic ossification was classified according to Brooker's classification on plain radiographs.
Results:
Heterotrophic ossification was significantly less in group 2 (4/202, 1.98%) as compared to group 1 (29/200, 14.5%). No severe heterotrophic ossification was found in group 2.
Conclusion:
Release of the superior-lateral capsular flap from the gluteus minimus muscle allows the femoral mobilization required during the femoral preparation and exposes the trochanter for easier retractor placement and thereby minimizes the muscular traumatic insult. When combined with aspirin and celecoxib chemoprophylaxis, this technique may diminish heterotrophic ossification.
