Roentgenographic measurements after Müller total hip replacement. Correlations among roentgenographic measurements and hip strength and mobility.

In fifty-two patients with Müller total hip replacement, roentgenographic measurements of prosthetic component positioning were correlated with hip-muscle strength and mobility measurements. Compared with the normal side, the average position of the center of the prosthetic head was more medial and superior in the pelvis, and the greater trochanter was more distal and lateral. Increasing neck length (distance from the center of the prosthetic head to the lesser trochanter) and a more distal position of the greater trochanter were among the measurements that related favorably to measurements of patient function. More superior placement of the center of the prosthetic head in the pelvis was associated with a more superior position of the lesser trochanter, which related adversely to function.