Understanding subtalar joint biomechanics and pathomechanics provides a framework for understanding both common pathologic hindfoot and forefoot conditions and surgical planning. It is important to identify mechanical impairment and to define what mechanical effect is needed to change a pathologic condition. It is also important to know what the initial problem is and what the consequences are in terms of soft tissue or bony stress leading to peritalar injury. Whenever possible, one should try to operate to change pathomechanics and facilitate spontaneous repair of stressed structures.