Effect of tibialis posterior tendon transfer on anatomical foot parameters and functional outcomes in patients with a drop foot

In patients with a drop foot, the transfer of the tibialis posterior tendon over the interosseous membrane to the lateral cuneiform on the dorsal side of the foot not only restores the function of the ankle but also eliminates the forces causing deformation on the medial side of the foot. In our study, cases in which tibialis posterior tendon transfer was performed due to a drop foot were examined. A total of 20 patients, 11 male and 9 female, who underwent surgery due to a drop foot were included in the study. The mean age was 38.45 (range 22-70). The right foot was affected in 11 patients and the left foot was affected in 9 patients. The mean duration of paralysis was recorded as 45.55 months (range 2-252 months). The mean follow-up period of the patients was 42.6 months (range 12-85 months). The tibialis posterior tendon was separated from the insertion area on the navicular, moved proximally to the midline of the cruris, and transferred to the dorsal side of the foot using the interosseous route. The tendon was fixed to the lateral cuneiform bone. The Stanmore Scoring System was used to evaluate the transfer results. According to the Stanmore score, excellent results were recorded in 6 patients (30%), good results in 6 patients (30%), moderate results in 4 patients (20%), and poor results in 4 patients (20%). The mean postoperative active dorsiflexion angle was 9° (Sd ± 5.6). When preoperative and postoperative radiographs were examined, it was found that the lateral talocalcaneal angle, lateral talus-1st metatarsal angle, and talohorizontal angle changes could be related to the duration of paralysis. Although these changes favored collapse in the MLA, no pes planus or other deformities were observed in the patients. Tibialis posterior tendon transfer in the treatment of drop foot reduces the use of orthosis in patients and provides quite successful results in terms of regaining active dorsiflexion of the foot.