Does Degenerative Lumbar Spine Disease Influence Femoroacetabular Flexion in Patients Undergoing Total Hip Arthroplasty?

• Published in: Clinical orthopaedics and related research 2016-08, Vol.474 (8), p.1788-1797
• Main Authors: Esposito, Christina I., Miller, Theodore T., Kim, Han Jo, Barlow, Brian T., Wright, Timothy M., Padgett, Douglas E., Jerabek, Seth A., Mayman, David J.
• Format: Article
• Language: English
• Subjects: Acetabulum - diagnostic imaging; Acetabulum - physiopathology; Acetabulum - surgery; Adaptation, Physiological; Adult; Aged; Arthroplasty, Replacement, Hip; Biomechanical Phenomena; Clinical Research; Conservative Orthopedics; Cross-Sectional Studies; Female; Femur - diagnostic imaging; Femur - physiopathology; Femur - surgery; Hip Joint - diagnostic imaging; Hip Joint - physiopathology; Hip Joint - surgery; Humans; Intervertebral Disc - diagnostic imaging; Intervertebral Disc - physiopathology; Intervertebral Disc Degeneration - diagnostic imaging; Intervertebral Disc Degeneration - physiopathology; Joint Diseases - diagnostic imaging; Joint Diseases - physiopathology; Lordosis - diagnostic imaging; Lordosis - physiopathology; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - physiopathology; Male; Medicine; Medicine & Public Health; Middle Aged; Orthopedics; Posture; Range of Motion, Articular; Spine; Sports Medicine; Surgery; Surgical Orthopedics; Treatment Outcome
• ISSN: 0009-921X; 1528-1132
• DOI: 10.1007/s11999-016-4787-2

Background Sitting pelvic tilt dictates the proximity of the rim of the acetabulum to the proximal femur and, therefore, the risk of impingement in patients undergoing total hip arthroplasty (THA). Sitting position is achieved through a combination of lumbar spine segmental motions and/or femoroacetabular articular motion in the lumbar-pelvic-femoral complex. Multilevel degenerative disc disease (DDD) may limit spine flexion and therefore increase femoroacetabular flexion in patients having THAs, but this has not been well characterized. Therefore, we measured standing and sitting lumbar-pelvic-femoral alignment in patients with radiographic signs of DDD and in patients with no radiographic signs of spine arthrosis. Questions/purposes We asked: (1) Is there a difference in standing and sitting lumbar-pelvic-femoral alignment before surgery among patients undergoing THA who have no radiographic signs of spine arthrosis compared with those with preexisting lumbar DDD? (2) Do patients with lumbar DDD experience less spine flexion moving from a standing to a sitting position and therefore compensate with more femoroacetabular flexion compared with patients who have no radiographic signs of arthrosis? Methods Three hundred twenty-five patients undergoing primary THA had preoperative low-dose EOS spine-to-ankle lateral radiographs in standing and sitting positions. Eighty-three patients were excluded from this study for scoliosis (39 patients), spondylolysis (15 patients), not having five lumbar vertebrae (7 patients), surgical or disease fusion (11 patients), or poor image quality attributable to high BMI (11 patients). In the remaining 242 of 325 patients (75%), two observers categorized the lumbar spine as either without radiographic arthrosis or having DDD based on defined radiographic criteria. Sacral slope, lumbar lordosis, and proximal femur angles were measured, and these angles were used to calculate lumbar spine flexion and femoroacetabular flexion in standing and sitting positions. Patients were aligned in a standardized sitting position so that their femurs were parallel to the floor to achieve approximately 90° of apparent hip flexion. Results After controlling for age, sex, and BMI, we found patients with DDD spines had a mean of 5° more posterior pelvic tilt (95% CI, −2° to −8° lower sacral slope angles; p < 0.01) and 7° less lumbar lordosis (95% CI, −10° to −3°; p < 0.01) in the standing position compared with patients without radiographic arthro