The fate of fibular osteotomies performed during high tibial osteotomy

High tibial osteotomy (HTO) is an important treatment alternative in isolated single compartment knee osteoarthritis. To achieve adequate mechanical axis corrections in the lower extremity fibula is also osteotomized concomitantly. The aim of this study was to compare the union rates of proximal and diaphyseal fibular osteotomies accompanying high tibial osteotomies. Sixty-seven knees of sixty-three patients who had undergone HTO were retrospectively evaluated. The patients were grouped according to the level of the fibular osteotomy (FO). In group I, the level of FO was proximal, and in group II, it was at the level of junction of middle and distal third of diaphysis. The union rates of FOs at two different levels were compared. The influence of the presence of displacement at the osteotomy site and apposition between bone ends on union was also evaluated. Fifty-nine of sixty-seven FOs (88.06 %) were united. The union rate of proximal FOs was significantly greater than diaphyseal osteotomies (p < 0.0001); 97.9 % of proximal FOs were united, whereas this ratio was 65 % for the diaphyseal FOs. The presence of displacement at the FO and apposition between bone ends significantly influenced the bony union rate (p values 0.035 and < 0.0001, respectively). Union rates and nonunion characteristics of FO might differ according to its level, apposition of bone ends, and contact area. The fate of FO might also affect the union of HTO.