Gluteus maximus contraction velocity assessed by tensiomyography improves following arthroscopic treatment of femoroacetabular impingement.

ABSTRACT

PURPOSE: Muscular impairment, particularly for the gluteus maximus (GM), has been observed in femoroacetabular impingement (FAI). The purpose of this study was to evaluate the tensiomyographic changes of the GM, rectus femoris (RF) and adductor longus (AL) before and after arthroscopic surgery for FAI. It was hypothesized that arthroscopic treatment of FAI would improve the preoperative muscular impairment. METHODS: All patients undergoing arthroscopic treatment of FAI between January and July 2015 were approached for eligibility. Patients included had a tensiomyography (TMG) evaluation including maximal displacement (Dm) and contraction time (Tc) of these muscles in both lower extremities. TMG values between the injured and healthy sides were compared at the preoperative and post-operative (3, 6 and 12 months after surgery) periods. RESULTS: There were no significant differences for the RF and AL, and Dm of the GM for any of the comparisons (n.s.). However, GM Tc was significantly lower at 3 (p = 0.016), 6 (p = 0.008), and 12 (p = 0.049) months after surgery in the injured side compared to preoperatively. GM Tc of the healthy side was significantly lower than the injured side at the preoperative period (p = 0.004) and at 3 (p = 0.024) and 6 (p = 0.028) months after surgery, but these significant differences were no longer observed at 12 months after surgery (n.s.). There was a significant reduction of pain in the GM area at 1 year after surgery compared to preoperatively (p < 0.0001). CONCLUSIONS: Arthroscopic treatment of FAI and the subsequent rehabilitation improves contraction velocity of the GM of the injured side. Despite Tc is elevated in the GM of the injured compared to the healthy side preoperatively and at 3 and 6 months after surgery, differences in Tc between both sides are no longer significant at 12 months. Athletes with FAI participating in sports with great involvement of GM may benefit from arthroscopic treatment and its subsequent rehabilitation. TMG can be used as an objective measurement to monitor muscular improvements of the GM after surgery in these patients. LEVEL OF EVIDENCE II.