A Rare But Important Complication After Fibular Osteotomy During Lateral Closing-Wedge High Tibial Osteotomy: Extension-Type Checkrein Deformity of the Hallux: A case report.

Abstract

Hallux motion disturbance after lateral closing-wedge high tibial osteotomy (LCW-HTO) is uncommon, and tendon-related complications following fibular osteotomy remain poorly recognized. We describe a case of extension-type hallux checkrein deformity caused by presumed extensor hallucis longus (EHL) tethering after LCW-HTO with fibular osteotomy and discuss its diagnostic and surgical implications. A man in his 40s developed abnormal hallux extension during ankle plantarflexion 6 months after LCW-HTO with concomitant fibular osteotomy. The deformity interfered with gait and shoe wear. Physical examination demonstrated rigid hallux extension during ankle plantarflexion with relief during dorsiflexion, while neurologic findings remained normal. Radiographs showed hypertrophic callus formation at the fibular osteotomy site, suggesting postoperative EHL tethering. During revision surgery, proximal excursion of the EHL was markedly restricted despite preserved distal tendon gliding. EHL-to-extensor digitorum longus tendon transfer was therefore performed instead of local release. Hallux motion recovered without recurrence, and the patient returned to work without functional limitation. This case highlights that postoperative hallux dysfunction after fibular osteotomy may reflect tendon tethering rather than neurologic injury. Dynamic ankle-dependent toe motion is an important diagnostic clue. When proximal adhesion is suspected and direct release is difficult, tendon transfer may provide a reliable surgical solution. LEVEL OF EVIDENCE: V.