Arthroscopic versus open treatment of cam-type femoro-acetabular impingement: retrospective cohort clinical study

Abstract

Purpose: The purpose of this study was to determine if there were significant differences between patients submitted to hip arthroscopy (HA) and surgical hip dislocation (SHD) to treat femoro-acetabular impingement (FAI), which variables were significantly associated with hip function before surgery and those predictive of the applied functional outcome scale and its variation rate after surgery.

Methods: We selected 198 patients treated with HA or SHD with a mean follow-up of 59 months. Inclusion criteria were ages 18-50 years, isolated FAI cam morphology and complete clinical and radiologic documentation. The subjective outcome measure used was the nonarthritic hip score (NAHS). We compared pre-operative and post-operative NAHS, alpha angles and complication rates. Multiple linear regression analyses were performed to find which variables could influence NAHS values.

Results: The mean alpha-angle value improved from 71.5° to 40.8°, and mean NAHS improved from 50 to 83 points, with no difference between groups (HA/SHD). We found only a 16.9% influence rate on the pre-operative score, explained by variables of gender/pre-operative alpha angle and presence of degenerative changes/age. The influence rate on the NAHS variation ratio after surgery was 62.8%, explained by the variables of pre-operative score, type of surgery and type of surgery/alpha angle. The complication rate was 7%.

Conclusions: FAI surgery can be considered effective in improving patient symptoms. There were no differences in clinical or radiographic results between techniques. We could more accurately predict the variation ratio of NAHS after surgery than its pre-operative value.

Keywords: Cam; Femoro-acetabular impingement; Hip arthroscopy; Nonarthritic hip score; Results; Surgical hip dislocation.