Total Hip Arthroplasty After Spinal Fusion Surgery.

Given the close functional connection between the hip and the spine, their simultaneous degenerative pathology is a common problem seen in orthopedic patients and has been termed the "hip spine syndrome". Demographic change and an increasing number of operations have led to more patients who have undergone both total hip arthroplasty and spondylodesis especially of the lumbar spine. Studies have shown significant dislocation rates in this cohort of as high as almost 30%. Biomechanical studies and considerations show that spinal surgery directly influences the functional acetabular position and, consequently, the position of the acetabular cup, making the correct implantation challenging for the hip surgeon. Spinal fusion affects not only the biomechanics of the spine but also of the hip joint and, for that reason, must accordingly be taken into account when planning total hip arthroplasty.