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 extension member is slidably connected to the first arm member and the second extension member is operatively connected to the third arm members, such that the second arm members travel along an arcuate path defined by the second extension member when the second arm member is moved from a first position to a second position relative to the first and third arm members. Furthermore, the position of the third arm member can be securedly adjusted relative the first arm member.