Prostheses for persons with lower-limb amputations: An extra joint increases range of motion

This report describes two cases in which the addition of an extra joint enhanced range of motion and improved function in persons with unilateral lower-limb amputation. Both individuals had significant disability in the workplace and at home before this modification. In the first case, an individual with a hemipelvectomy had inadequate hip-joint flexion for maneuvering during photo shoots. In the second case, the individual's transfemoral prosthesis provided insufficient knee flexion for kneeling and working in tight spaces. In each case, a manual-locking, single-axis knee joint was added adjacent to the joint with the limited range of motion. In both cases, the addition of the second joint provided the increased flexibility needed. The first person's hip-flexion range improved from 125°to 190°, and the second person's knee-flexion range improved from 140°to 170°. In repeated follow-up, both patients remained highly satisfied with the intervention. The addition of an extra joint is an option that should be considered when inadequate range interferes with function.