An orthosis for stretching tissue around a joint of a patient between first and second relatively pivotable body portions. The orthosis includes a first arm member affixable to the first body portion and including a first extension member extending therefrom. A second arm member affixable to the second body portion is also included and has a second extension member having an arcuate shape extending therefrom. A third arm member including a third extension member having an arcuate shape extending therefrom is interposed between the first and second arm members. The third arm member is operatively connected to the first and second arm members, such that the first and third arm members travel along an arcuate path defined by the second extension member when the third arm member is moved from a first position to a second position relative to the second arm member. Furthermore, the first arm member can slide along the third extension member as the third arm member is moved from the first position to the second position relative to the second arm member.