[Comparison of the effect of total hip arthroplasty through mini invasive direct anterior approach during learning curve period and posterolateral approach for the treatment of femoral head necrosis].

Objective: To compare clinical results of treating femoral head necrosis staged Ficat III or IV with total hip arthroplasty (THA) between mini invasive direct anterior approach (DAA) and posterolateral approach.

Methods: From January 2008 to December 2009, 48 patients with femoral head necrosis staged Ficat III or IV treated with THA were compared and analyzed. There were 21 patients in mini invasive direct anterior approach group including 11 males and 10 females with an average age of (65.2±4.3) years old;while there were 27 patients in posterolateral approach group including 16 males and 11 females with an average age of (63.6±4.0) years old. Operative time, blood loss during operation, bed rest time and complications of two groups were observed and compared. Acetabular abduction and stem shaft angle were measured 1 month after operation and compared between two groups. Postoperative Harris Hip scoring and VAS scoring were applied for evaluating hip function and pain at 1, 6 months and 5 years after operation respectively.

Results: All patients were followed up for 48 to 73 months with an average of 60.4 months. Operative time, blood loss in DAA group was (78.30±5.08) min, (351.30±21.46) ml, respectively, in posterolateral approach group was (75.61±10.60) min, (362.20±26.15) ml, and no significant differences between two groups. Bed rest time in DAA group was (2.05±1.10) days, better than that of in posterolateral approach which was (3.30±1.35) days. No significant differences were found between two groups in acetabular abduction and stem shaft angle at 1 month after operation. There was no significant differences between two groups in HHS and VAS score at 1, 6 months and 5 years after operation. There was 1 case with injury of ascending branch of the lateral circumflex femoral artery, 1 case with great trochanter fracture and 1 case with superficial infection in DAA group, 1 case with dislocation in posterolateral group. No prosthesis loosening occurred in two groups.

Conclusions: Both DAA and posterolateral approach are effective in treating femoral head necrosis staged Ficat III or IV, and could obtain excellent outcomes. However, DAA seemed to has disadvantage in learing curve compared posteriolateral approach in complex cases.