Effect of Combined Fibular Osteotomy on the Pressure of the Tibiotalar and Talofibular Joints in Supramalleolar Osteotomy of the Ankle: A Cadaveric Study.

We investigated the effect of combined fibular osteotomy on the pressure of the tibiotalar and talofibular joints in medial opening-wedge supramalleolar osteotomy. Three different tibial osteotomy gaps (6, 8, and 10 mm) were created in 10 cadaveric models, and the pressure in the tibiotalar and talofibular joints was measured under axial load before and after fibular osteotomy. The heel alignment angle and talar translation ratio were evaluated radiographically. An increase in osteotomy gap led to increases in hindfoot valgus (p = .001) and the contact and peak pressures in the talofibular joint (p = .03 and p = .004). In contrast, the contact and peak pressures in the tibiotalar joint were unchanged with an increasing osteotomy gap (p = .52 and p = .76). Fibular osteotomy reduced the contact and peak pressures in the talofibular joint (p < .001 and p = .001, respectively), and it did not influence the contact and peak pressures in the tibiotalar joint (p = .46 and p = .14, respectively). Therefore, fibular osteotomy might be necessary in supramalleolar osteotomy for medial ankle arthritis to minimize the increase in pressure in the talofibular joint, especially when the osteotomy gap is large.