Despite the curvaceous profile of the acetabulum, orthopaedic surgeons have continued to implant hemispheric cups since the
introduction of total hip arthroplasty. The geometric discrepancies between the natural acetabulum and implant can result
in painful iliopsoas impingement attributable to prosthetic overlap at the anterior acetabular ridge over which the iliopsoas
tendon extends to leave the pelvis. We expanded on previous in vitro observations of acetabular morphology using a large in vivo
sample and quantified the dimensions of the psoas valley. We studied computed tomographic scans of 200 healthy hips from 50
men and 50 women. The acetabular ridges were digitized on three-dimensional bone reconstructions and their coordinates were
manipulated in spreadsheets to deduce acetabular diameter, anteversion, and inclination and to plot the rim profile. Our results
confirm the acetabular rim is an asymmetric succession of three peaks and three troughs. The psoas valley has the following
shape distribution: 79% curved, 11% angular, 10% irregular, and 0% straight. The mean depth of the psoas valley is 5 mm and
the latitude of its trough is on average 6 mm below the acetabular equator. The use of side-specific cups that replicate the
curvaceous acetabular profile could prevent prosthetic overlap and reduce the incidence of iliopsoas impingement.
Each author certifies that he or she has no commercial associations (e.g., consultancies, stock ownership, equity interest,
patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution has waived approval for the human protocol for this investigation and that
all investigations were conducted in conformity with ethical principles of research.