Thursday, September 27, 2018 8:30 AM–9:30 AM Best Papers: 108. Spinopelvic compensatory mechanisms for reduced hip motion (ROM) in the setting of hip osteoarthritis

• Published in: The spine journal Vol. 18; no. 8; pp. S52 - S53
• Main Authors: Steinmetz, Leah, Zhou, Peter L, Frangella, Nicholas J., Stekas, Nicholas, Varlotta, Christopher, Ge, David H., Vasquez-Montes, Dennis, Lafage, Virginie, Lafage, Renaud, Vigdorchik, Jonathan M., Passias, Peter G., Protopsaltis, Themistocles S., Buckland, Aaron J.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.08.2018
• ISSN: 1529-9430; 1878-1632
• DOI: 10.1016/j.spinee.2018.06.373

Spinopelvic compensatory mechanisms for reduced hip motion (ROM) in the setting of hip osteoarthritis. Hip osteoarthritis (OA) results in reduced hip range of motion, which affects sitting and standing posture. Spinal pathology (eg, fusion or deformity) may alter the ability to compensate for reduced joint mobility associated with hip OA in sitting and standing postures; however, the effect of hip OA on postural spinal alignment between sitting and standing remains unreported. In patients with severe hip OA, spinopelvic compensatory mechanisms can be compromised leading to greater pelvic tilt (PT) and lumbar lordosis (LL) change. Retrospective clinical and radiographic analysis at a single institution of patients with OA between 2012 and 2017. A total of 548 patients with sit-stand radiographs. Spinal and lower limb alignment Pelvic Incidence (PI), PT, LL, PI-LL, Thoracic Kyphosis (TK), Global alignment (SVA & T1-Pelvic Angle (TPA), T10-L2, proximal femoral shaft angle (PFSA: as measured from the vertical), sacrofemoral angle (SFA), Knee Flexion (KA) and hip ROM (difference between PT change and PFSA change). Hip OA severity was graded by Kellgren-Lawrence scale and divided into two groups: low-grade (LOA; grades 0-2) and severe (SOA; grades 3-4). Patients were excluded if they had transitional lumbosacral anatomy, prior spinal fusion or hip prosthesis. Changes in sit-stand alignment were compared between LOA and SOA by unpaired t-test A total of 548 patients were identified with sit-stand radiographs, of which there were 311 patients with LOA and 237 with SOA. After propensity score matching for age, BMI, PI and standing SVA, 183 LOA & 183 SOA patients were analyzed. Standing alignment analysis demonstrated that SOA patients had lower PT (14.49 ± 9.2 vs. 16.78 ± 8.14, p<.001), greater PI-LL (0.82 ± 12.17 vs. 0.09 ± 11.9, p<.001), lower LL (53.03 ± 13.11 vs. 54.24 ± 12.2, p<.001), lower T10-L2 (−0.22 ± 10.07 vs. −1.36 ± 11.1 p=.05), lower TK (−36.32 ± 12.18 vs. −40.43 ± 11.62, p=.01), and lower TPA (12.68 ± 8.71 vs. 13.65 ± 8.74, p=.01). SVA and PFSA were not significantly different compared to LOA. Sitting alignment analysis demonstrated that SOA patients had higher PT (29.4 ± 15.09 vs. 24.68 ± 12.07, p<.001), lower LL (32.14 ± 16.43 vs. 39.81 ± 14.23, p<.001), higher T10-L2 (−4.7 ± 10.69 vs. −2.35 ± 11.87, p=.05), lower TK −33.47 ± 16.14 vs. −37.52 ± 13.5, p=.01), greater TPA (27.53 ± 13.85 vs. 23.98 ± 11.09 p=.01), and greater PFSA (9.09 ± 5.19 vs. 7.41± 4.48, p<.001). PI-LL and SVA was not significantly different compared to LOA. SOA and LOA groups demonstrated differences in standing and sitting spinopelvic alignment for all global and regional parameters except PI, SVA, SFA and KA. When examining the postural changes from standing to sitting, hip ROM was less in SOA than LOA (71.95 ± 17.7 vs. 80.67 ± 12.69, p<.001). As a result, SOA patients had more change in PT (14.91 vs. ± 16.01 vs. 7.9 ± 10.16, p<.001), PI-LL (20.35 ± 16.84 vs. 14.88 ± 11.56, p<.001), LL (−20.89 ± 15.4 vs. −14.41 ± 12.59, p<.001), and T10-L2 (−4.48 ± 7.16 vs. −0.9 ± 5.39, p<.001) to compensate. SOA group had a small but statistically significant improvement in SVA (28.31 vs. 37.43, p=.04), more change in TPA (14.85 vs 10.35, p<.001), and less change in PFSA (86.65 vs. 88.81, p<.001) compared to LOA. TK change was not significantly different compared to LOA. Spinopelvic compensatory mechanisms are adapted for reduced hip ROM in SOA between standing and sitting. This abstract does not discuss or include any applicable devices or drugs.