RESUMEN
Checkrein deformity is a rare entity that results in alteration of the normal flexion and extension of the hallux, caused by a retraction or adhesion of the flexor hallucis longus (FHL) in its tendinous or muscular portion. It is usually caused by the sequelae of ankle and tibia fractures, such as adhesions and neuropathies, and often undiagnosed compartment syndromes. Its treatment is mainly surgical, and different techniques of release or lengthening of the FHL have been described. We present the clinical case of a 61-year-old patient treated by a simple arthroscopic tenotomy of the FHL at the retromalleolar level of the ankle, with complete functional recovery and absence of recurrence after 2 years of evolution. We recommend that this procedure should be considered for this pathology due to its technical simplicity, low iatrogenicity, early recovery, and theoretical absence of recurrence.Level of Evidence: Level V: Expert opinion, case report.