Compensatory Function of the Subtalar Joint for LowerExtremity Malalignment

It is important to evaluate the subtalar joint and hip-knee-ankle alignment to understand lower extremity alignment. In this review,we focused on the compensatory changes in the subtalar joint alignment for the deformity of the knee and ankle joint, reviewingprevious research. The subtalar joint alignment was compensatory valgus in patients with varus knee and ankle deformity, whereasit was uncertain whether the subtalar joint alignment was compensatory varus in patients with valgus knee and ankle deformity.The subtalar joint valgus alignment improved after total knee arthroplasty or high tibial osteotomy for varus knee deformity, evenif the deformity was severe. In contrast, whether the subtalar joint alignment changed after the surgery for ankle or valgus kneedeformity has not been considered. Further research on the compensatory function of the subtalar joint is needed.