Ultrasound-guided release of post-arthroscopy extra-articular hip adhesions in femoroacetabular impingement: a novel technique

OBJECTIVE: To explore a novel ultrasound-guided injection technique of releasing extra-articular anterior hip adhesions in arthroscopically treated femoroacetabular impingement patients. MATERIALS AND METHODS: IRB-approved pilot study included 24 consecutive patients referred for ultrasound-guided injection (Jan 1, 2017–Mar 31, 2018) with anterior hip pain and/or limited hip flexion following arthroscopic treatment for femoroacetabular impingement. They underwent ultrasound-guided pressure injection, releasing post-operative extra-articular adhesions between the joint capsule and flexor tendons along the arthroscopic portal followed by steroid instillation. A visual analogue pain score of 0–10 and standard Hip Outcome Score was used to record treatment response pre-injection, at 6 weeks and at 6 months following injection. RESULTS: Nine out of 11 patients (complete data group) who answered all questionnaires showed response to injection with improvement in Hip Outcome Scores at 6 weeks and 6 months. Three out of 10 patients (incomplete data group) showed significant response to injection from clinical follow-up records. No records were available in 3 patients. In total, 12 (57.14%) out of 21 patients showed response to injection. No post-procedure complications. CONCLUSION: Ultrasound-guided pressure injection is a novel, safe, and effective procedure providing pain relief and improved hip movement as evaluated in our small sample study. The limitations of this pilot project include small sample size, lack of control group, short 6-month follow-up, and single institution study. This minimally invasive technique could be a cost-effective alternative to surgical adhesiolysis and can potentially be extended for extra-articular adhesions at other peripheral joints, amenable to ultrasound.