Hip stiffness patterns in lumbar flexion- or extension-based movement syndromes

Objective To determine whether a relationship exists between sagittal plane hip range of motion loss and sagittal plane lumbar Movement System Impairment (MSI) categories in patients with low back pain (LBP). Design Correlational study. Setting University outpatient physical therapy clinic. Participants Subjects (N=40) with LBP. Interventions Not applicable. Main Outcome Measures Classification into a flexion- or extension-based lumbar MSI category, and bilateral passive hip flexion and extension range of motion testing. Using predefined criteria, subjects in each MSI category were subclassified into 1 of 3 hip stiffness categories: (1) a considerable loss of either flexion or extension (pattern A); (2) a considerable loss of both flexion and extension (pattern B); or (3) minimally limited flexion or extension (pattern C). Results Pattern A occurred in 23 (57.5%) subjects, with the primary direction of hip motion loss agreeing with the MSI category 78.3% of the time (φ=.56; P=.007). Pattern B occurred in 10 (25%) subjects, with the primary direction of hip motion loss agreeing with the MSI category 70% of the time (φ=.47; P=.197). Pattern C occurred in 7 (17.5%) subjects, with the primary direction of hip motion limitation agreeing with the MSI category 42.9% of the time (φ=-.40; P=.290). Conclusions Considerable unidirectional hip motion loss in the sagittal plane was a common finding among subjects with LBP and yielded a strong positive relationship with the same direction MSI category. These results may inform future studies investigating whether treatment of hip stiffness patterns could improve outcomes in LBP management.