Measurements of the functional performance of thirty patients with osteoarthritis, rheumatoid arthritis, and avascular necrosis of the femoral head were made before and three and six months following McKee-Farrar total hip replacement and were then compared. The measurements included: range of hip motion, hip abductor and adductor muscle torque, position of the center of pressure of the supportive force during standing, amplitude of force applied to assistive devices during walking, and ten previously described components of walking performance. The measurements were also compared with normal standards. Finally, roentgenographic evaluations and the patients' ratings of the surgical result were analyzed.

Twenty-seven of the thirty patients were considered to have pronounced improvement on the basis of the functional tests and the subjective ratings. One patient, who had a severe staphylococcal wound infection, became much worse in every component of function. The remaining two patients who did not show satisfactory improvement were: a patient with chronic alcoholism who was totally uncooperative throughout the postoperative course and a patient who had a series of postoperative complications which were unrelated to his hip replacement.

The quantitative values presented in this study provide a basis for comparing the functional performance following other major reconstructive procedures on the hip.