Abstract
Introduction: We investigated the effects of lower back pain (LBP) on measures of pain, disability, and function in highly symptomatic hip OA patients receiving intra-articular steroid injection (IASI) therapy. We also investigated the effect of radiographic severity of hip OA for comparison to LBP. Methods: 97 consenting subjects with symptomatic hip OA presenting for IASI were evaluated at baseline, assessed over an 8-week period, and followed at least 1 year later for new arthroplasty. At baseline and 8 weeks follow-up patient demographics, presence/absence of back pain, physical function tests, a single anteroposterior pelvis x-ray, and subjective scores of pain, stiffness and function (VAS and WOMAC) were collected. We also followed which subjects proceeded to obtain total hip arthroplasty in the examined hip. Results: Cohorts with LBP reported significantly worse scores for all of VAS pain and WOMAC questionnaires but showed no difference in ROM and were not more likely to proceed to arthroplasty. Cohorts with severe radiographic OA had significantly worsened scores for stiffness (χ2 = 6.74, p = 0.009), decreased ROM (p < 0.01), and were more likely to proceed to arthroplasty (χ2 = 9.79, p = 0.044). Discussion: Back pain has a substantial effect on clinical parameters relevant to assessment of severity of hip OA, especially self-reported pain and function. This finding highlights LBP as a significant confounding factor in hip OA patient assessments and will inform future studies to determine the most effective treatment strategies for hip OA patients. © The Author(s) 2020.