Recent evidence suggests that abnormal hip morphology may be the primary cause of osteoarthritis of the hip in young adults1-5. Hip pathomorphology is manifested as acetabular deficiency or malorientation, or as femoral deformity or malorientation, and most commonly as a combination of these problems6,7. Contemporary surgical intervention for hip preservation has been directed toward correction of these malformations and associated chondrolabral injuries and has shown promise as a way of alleviating hip pain and possibly retarding the progression of osteoarthritis8,9. With the increasing number of available surgical methodologies (e.g., surgical dislocation, osteochondroplasty, hip arthroscopy, and redirectional acetabular osteotomy) that are directed at hip preservation, the importance of understanding the pathologic process that results in a painful hip has become paramount. In an effort to augment the basic information obtained from clinical examination, two-dimensional plain radiography, and magnetic resonance arthrography, we have utilized a validated three-dimensional modeling protocol to serve as a diagnostic and surgical planning tool for hip-preservation surgery. Three-dimensional modeling has helped to emphasize the complex pathomorphology that is evident in patients with hip dysplasia and femoroacetabular impingement and may have a future role in the classification and treatment of hip maladies in young adults.