Modified arthroscopic excision of the symptomatic os trigonum and release of the flexor hallucis longus tendon: operative technique and case study.

This article presents an operative technique for modified arthroscopic excision of the symptomatic os trigonum and release of the flexor hallucis longus tendon sheath. The procedure uses two stacked posterolateral subtalar joint portals, rather than the customary anterolateral and posterolateral portal combination. By visualizing the os trigonum with an arthroscope positioned in a distal portal and introducing instrumentation through a proximal portal, the ossicle may be quickly exposed and excised with minimal dissection. A case study with a 22-month follow-up and a discussion of os trigonum syndrome are included to illustrate this procedure as an alternative to open excision or traditional arthroscopic excision.