Abstract
Objective: The purpose of this study was to evaluate the factor of joint space narrowing (JSN) from the perspective of femoroacetabular impingement on postoperative patients who had undergone surgery for slipped capital femoral epiphysis.
Methods: After a mean follow-up of 7.7 years, we reviewed 19 hips in 17 patients who had undergone surgery for slipped capital femoral epiphysis. The mean age at the time of surgery was 12.7 years. The type of surgeries were in situ pinning in 7 hips, pinning after reposition in 1 hip, simple flexion osteotomy in 2 hips, Southwick osteotomy in 4 hips, and Sugioka’s osteotomy in 5 hips. We investigated the frequency of JSN and the relationship between JSN and various factors (neck-shaft angle, CE angle, AC angle, postoperative posterior tilting angle, cross-over sign, posterior wall sign, medial proximal femoral angle, alpha angle, head-neck offset ratio, and bony prominence).
Results: JSN was found in six hips (32%). All JSN in these hips was less than 2 mm. JSN was correlated with the head-neck offset ratio (P = 0.003) and bony prominence (P = 0.04).
Conclusion: We found significant correlation between the head-neck offset ratio and bony prominence, and these factors were associated with cam type impingement and JSN. However, further longitudinal studies are required to confirm whether a cam-type deformity will ultimately develop to progressive osteoarthritis.
