Lever arms acting on hip joint. A, Moment produced by body weight applied at body’s center of gravity, X, acting on lever arm, B-X, must be counterbalanced by moment produced by abductors, A, acting on shorter lever arm, A-B. Lever arm A-B may be shorter than normal in arthritic hip. B, Medialization of acetabulum shortens lever arm B₁-X, and use of high offset neck lengthens lever arm A₁-B₁. C, Lateral and distal reattachment of osteotomized greater trochanter lengthens lever arm A₂-B₂ further and tightens abductor musculature.