CORR Insights^®: Does Degenerative Lumbar Spine Disease Influence Femoroacetabular Flexion in Patients Undergoing Total Hip Arthroplasty?

Excerpt

Lazennac and his colleagues [4, 5] were the first to inform the orthopaedic community about the importance of the spine-pelvic-hip relationship. Hip surgeons had not considered that the acetabulum changed position with postural change. They described the tilt of the pelvis being connected to the lordosis of the spine. Therefore, the pelvis was tilted anteriorly when standing with the acetabulum relatively closed. When sitting, the pelvis tilts posteriorly as the spine straightens, and the acetabulum opens with both inclination and anteversion to allow clearance of the flexed femur. Their research showed that spinopelvic mobility was crucial to avoiding impingement of the components of the hip replacement, or bony impingement, during both extension and flexion of the hip. If there is spinal imbalance such as degenerative disc disease with either stiffness or hypermobility of the spine/pelvis in 40% of their patients undergoing hip replacement, as described by the authors of the current study, it translates to a change in the pelvic mobility, which changes the acetabular opening between standing and sitting. In these patients, total hip replacement surgeons must control the acetabular opening mechanically with both the inclination and anteversion of the cup to compensate for the spinal imbalance that is present. Imbalance is undoubtedly higher in patients who require revision hip replacement because as patients age, their spine becomes stiffer. …