Closed atraumatic flexor hallucis longus tendon rupture following hallux valgus correction repaired using a turn down flap

A case report of closed atraumatic rupture of flexor hallucis longus (FHL) tendon few months after hallux valgus correction in a high functioning individual is presented. There have been only two cases of FHL tendon rupture reported following hallux valgus correction in literature till now. Our patient underwent Hallux valgus corrective osteotomy, 4 months after which he presented with rupture of the FHL tendon, he subsequently underwent successful surgical turn down flap repair with good clinical outcome. Closed atraumatic rupture of FHL tendon as an isolated injury is a rare event evidenced by systematic review reporting only 10 cases in literature till now. Low clinical suspicion of FHL rupture in closed foot injuries could be one factor resulting in fewer cases being reported in literature. Acute rupture of FHL tendon following open foot injuries and partial closed rupture due to tendinitis in dancers have been reported frequently in literature. In conclusion, we emphasize careful handling of FHL tendon while performing corrective osteotomy of the hallux in any patient. Although, turn down flap is a well-documented technique to bridge gaps and repair chronic tendo-achilles rupture, we were able to replicate the same technique in our patient and produce good functional result using this effective tendon repair technique to bridge segmental gap as evidence by return of almost normal power of great toe plantar flexion.