Incremental Impact of Lower Extremity Arthritis and Cervical Deformity on Patient-Reported Outcome Measures in Thoracolumbar Spinal Deformity Patients.

Abstract

Background and objectivesThoracolumbar spinal deformity frequently coexists with cervical spine deformity (CD) and lower extremity osteoarthritis (OA), complicating management and compounding functional disability. This study investigates the additive burden of these conditions on patient-reported outcome measures (PROMs).MethodsThis retrospective analysis assessed primary thoracolumbar deformity patients undergoing corrective surgery. Demographics, spinopelvic alignment, and PROMs were characterized. Severe CD was defined by ≥1 Ames criterion. Hip (HOA) and knee (KOA) OA were defined as Kellgren-Lawrence grade ≥3. Hierarchical regression and mixed-effects models evaluated the incremental and longitudinal impacts of these conditions on PROMs.ResultsAmong 816 patients (mean age 60.4 years, 67.1% female), 24.8% had CD, 43.7% HOA, and 40.4% KOA at baseline. Regression revealed that HOA worsened Oswestry Disability Index (ODI) total (R2 = 0.056, P = .008), ODI Walking (R2 = 0.121, P <.001), Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (R2 = 0.108, P = .013), and Veterans RAND 12-Item Health Survey (VR-12) Physical Component Score (PCS) (R2 = 0.098, P = .022). KOA primarily affected pain and psychosocial outcomes, including ODI Pain (R2 = 0.033, P = .001), PROMIS Depression (R2 = 0.018, P = .002), Scoliosis Research Society-22 Mental (R2 = 0.033, P = .004), and VR-12 Mental Component Score (R2 = 0.023, P = .025). CD contributed to ODI (R2 = 0.063, P = .018) and Scoliosis Research Society-22 Activity (R2 = 0.044, P = .032). Mixed-effects models showed improvements in all PROMs from baseline to 2-year follow-up (P <.001). However, HOA reduced improvements in ODI (3.41 points, P = .009), PROMIS Physical Function (1.37 points, P = .009), and VR-12 PCS (2.21 points, P = .003). KOA was associated with reduced walking tolerance (ODI Walking: 0.21 points, P = .020) and increased psychological burden (PROMIS Anxiety: 1.71 points, P = .007; VR-12 MCS: 2.01 points, P = .027). CD affected ODI Walking (0.51 points, P = .007) and VR-12 PCS (3.19 points, P = .043).ConclusionHOA patients undergoing deformity correction have worse preoperative physical disability and impaired postoperative functional recovery. KOA is associated with greater psychological burden. Severe CD has smaller physical impact. These findings highlight the need for individualized, multidisciplinary management strategies, with particular emphasis on early identification and targeted intervention for hip pathology to optimize outcomes.