[Precision-fit surface hemiarthroplasty of the hip for the treatment of the femoral head osteonecrosis].

Objective: To evaluate the outcome of precision-fit surface hemiarthroplasty in the treatment of femoral head osteonecrosis.

Methods: The clinical data of 41 patients (48 hip joints) with femoral head osteonecrosis were reviewed. Of them, 30 were male and 11 were female, average age was 37 years old (ranging from 29 - 49). Thirty-five patients were at Ficat stage III and 13 at Ficat stage IV, their acetabula were relatively normal. The 41 patients (48 hip joints) underwent precision-fit surface hemiarthroplasties.

Results: The mean duration of follow-up was 5.2 years. The average UCLA hip score at follow-up was improved significantly from 3.1 to 9.1 points for pain, 4.4 to 9.2 points for walking, and 5.5 to 7.1 points for activity (P = 0.001). The satisfaction rate was 88.6% for 35 at Ficat stage III, 69.2% for 13 at stage IV (P = 0.25). Eight hips failed; the UCLA hip score was not improved significantly; the postoperative X-ray examination showed that 7 femoral prostheses were implanted in a varus orientation (the angle between the femoral prosthesis stem and the anatomic axis of the femoral shaft was lower than angle of 130 degrees). Five-year survival rate was 83.0%.

Conclusions: Precision-fit surface hemiarthroplasty of the hip has the satisfactory result in treatment of the femoral head osteonecrosis on the basis of observing strictly operative indications and improving operative technique.