How to Screen for Lumbar Spine Stiffness in Patients Awaiting Total Hip Arthroplasty.

BACKGROUND: This study aimed to (1) define the prevalence of spinopelvic abnormalities among patients who have hip osteoarthritis (OA) and controls (asymptomatic volunteers) and (2) identify factors that reliably predict the presence of lumbar spine stiffness. METHODS: This is a prospective, cross-sectional, case-cohort study of patients who have end-stage primary hip OA, who underwent primary total hip arthroplasty (THA). Patients were compared with a cohort of asymptomatic volunteers, matched for age, sex, and body mass index (BMI), serving as a control group. Spinopelvic pathologies were defined as: lumbar spine flatback deformity (difference of 10 or more degrees for pelvic incidence minus lumbar lordosis angle), a standing sagittal pelvic tilt of 19° or more and lumbar spine stiffness (lumbar flexion of less than 20° between both postures). RESULTS: The prevalence of spinopelvic pathologies was similar between patients and controls (flatback deformity: 16% versus 10%, P = .209; standing pelvic tilt >19°: 17% versus 24%, P = .218; lumbar spine stiffness: 6% versus 5%, P = .827). Age over 65 years-old and standing lumbar lordosis angle less than 45° were associated with high sensitivity and specificity for identifying lumbar spine stiffness (age >65 years: 82% and 66%; standing lumbar lordosis angle <45°: 85% and 73%). CONCLUSION: The presence of end-stage hip osteoarthritis was not associated with increased prevalence of adverse spinopelvic characteristics compared to matched, asymptomatic volunteers. Age and LLstanding are the strongest predictors of lumbar spine flexion and can guide clinical practice on when to obtain additional radiographs for patients who have hip OA before arthroplasty to identify at-risk patients. LEVEL OF EVIDENCE: II (prospective, cohort study).

Younger Patients Are Differentially Affected by Stiffness-Related Disability Following Adult Spinal Deformity Surgery.

OBJECTIVE: The Lumbar Stiffness Disability Index (LSDI) assesses impact of lumbar stiffness on activities of daily living. We hypothesized that patients <60 years old would perceive greater lumbar stiffness-related functional limitation following fusion for adult spinal deformity. METHODS: Patients completed the LSDI and Scoliosis Research Society 22 Questionnaire, Revised (SRS-22r) preoperatively and at 2 years postoperatively. The primary independent variable was patient age <60 versus ≥60. Multivariable regression analyses were used. RESULTS: Analysis included 267 patients. Patients <60 years old (51.3%) and ≥60 years old (48.7%) were evenly represented. In bivariable analysis, patients age <60 exhibited lower LSDI at baseline versus patients age ≥60 (25.7 vs. 35.5, ß -9.8, P < 0.0001), but a directionally smaller difference at 2 years (26.4 vs. 32.3, ß -5.8, P = 0.0147). LSDI was associated with lower SRS-22r total score among both age groups at baseline and 2 years (all P < 0.0001); the association was stronger among patients age <60 versus ≥60 at 2 years. LSDI was associated with SRS-22r satisfaction scores at 2 years among patients age <60 (P < 0.0001), but not patients age ≥60 (P = 0.2250). The difference in SRS-22r satisfaction per unit LSDI between patients <60 years old and ≥60 years old was significant (P = 0.0021). CONCLUSIONS: Among patients with adult spinal deformity managed operatively, higher LSDI was associated with inferior SRS-22r total score and satisfaction at 2 years postoperatively. The association between increased LSDI and worse patient-reported outcome measures was greater among patients age <60 versus ≥60. Preoperative counseling is needed for patients age <60 undergoing adult spinal deformity surgery regarding effects that lumbar stiffness may have on postoperative function and satisfaction.