Rationale of osteotomy and related procedures for hip preservation: a review.

Most osteoarthrosis of the hip results from chronic abnormal hip mechanics, often associated with instability, impingement, or combinations of instability and impingement. The etiology of the mechanical problems in many hips is a surgically treatable anatomic abnormality, often a developmental deformity (dysplasia, Perthes disease, slipped epiphysis, femoral or acetabular retroversion, or reduced head-neck offset). The rationale of mechanically-based measures to prevent or treat osteoarthrosis assumes the following: (1) correctable mechanical overload is a major etiologic factor in osteoarthrosis; and (2) relief of the mechanical overload can prevent or improve osteoarthrosis. The success of such mechanically-based joint-preserving measures depends largely on the completeness with which the joint-preserving treatment normalizes the mechanical environment of the hip. A limiting factor often is the amount of irreversible articular damage that is present at the time treatment is begun.