Good results for treatment of flexor hallucis longus (stenosing) tenosynovitis: a systematic review

Importance Nowadays, it is unclear what kind of non-operative and operative treatment protocols exist for flexor hallucis longus (FHL) (stenosing) tenosynovitis and to what extent conservative treatment is effective. Objective The purpose of this study was to evaluate the literature on treatment of FHL (stenosing) tenosynovitis and to provide an overview of the different treatment options as well as an analysis, evaluation and comparison of their outcomes. Evidence review A structured systematic review of literature was performed to identify non-operative and operative therapeutic studies reporting on five or more patients with FHL (stenosing) tenosynovitis. Medline, Embase (Classic), Cumulative Index to Nursing and Allied Health Literature, Sportdiscus and Pedro databases were searched. Two reviewers independently performed data extraction. Extracted data consisted of population characteristics, treatment, outcome of treatment. The primary outcome was success rate. The secondary outcomes were patient satisfaction, complication rate, return to sport and the time to achieve return to sport or full activity after treatment. The Coleman score was used to assess the methodological quality of the studies. Findings Six articles were included. The number of patients in these studies totalled 138 with 151 affected ankles. Overall good results were found for treatment of FHL (stenosing) tenosynovitis. Specific exercises to stretch the FHL are successful in 64%. An injection with 1% lidocaine to inflate the FHL tendon sheath is successful in 33%. If conservative treatment fails, operative treatment can offer a solution. There are open and endoscopic techniques for release of the FHL tendon and all the techniques have a successful outcome. All athletes return to sport after an average of 5 weeks and 90% of the athletes have a full return to sport after a mean time of 4 months. Conclusion There are many conservative treatment options mentioned for FHL tenosynovitis; nevertheless only outcomes of stretching and lidocaine injections are reported. If conservative treatment does not give sufficient relief of symptoms, operative treatment, by releasing the FHL by an arthroscopic or open technique, offers a safe and effective solution. Thereby, arthroscopic techniques are promising; however, there is a paucity of literature on this issue. Relevance It is important to know what kind of conservative and operative treatments are effective for FHL (stenosing) tenosynovitis. Level of evidence Level IV.