Tibial Nerve injury in Medial Open Wedge-High Tibial Osteotomy - A Rare Complication with 14-Year Follow-Up.

Introduction: Medial open wedge-high tibial osteotomy (MOW-HTO) is a standard procedure for treating moderate varus arthritis in active adults. The reason for its popularity is having lesser complications than other types of HTO. However, it is not devoid of challenges. We report tibial nerve injury in a MOW-HTO which is a rare complication not reported much in the past.

Case report: A 56-year-old female was operated with MOW-HTO using TomoFix plate for medial joint arthritis and varus malalignment. She developed signs of tibial nerve injury, namely inability to flex the great toe and paresthesia over posterolateral leg and sole of foot. The nerve conduction velocity study confirmed tibial nerve damage with moderate axonotmesis. The patient was treated conservatively with electrical stimulation, interferential current therapy, physiotherapy, and pregabalin. The osteotomy outcome was good with complete union and good angle correction. At the end of 14 years, the motor function was fully recovered, but the patient still had residual paresthesia. After eliminating all other possible causes, the authors concluded that the etiology of the nerve damage was stretch injury. Smaller incisions are related to excessive retraction leading to unreasonable stretching of the soft tissues and nerves. To avoid such injuries during MOW-HTO, the authors propose an adequate length of incision along with other steps like subperiosteal Hohmann placement to protect neurovascular structures, flexing the knee during the procedure, maintaining posterior position of the plate, and using proper size screws. The main goal of this study is to make surgeons conscious about this rare but possible complication of MOW-HTO.

Conclusion: Surgeons need to be aware about this rare complication in MOW-HTO surgery and should be vigilant in recognizing its post-operative signs.