Back pain and total hip arthroplasty: a prospective natural history study

Abstract

Background: Many patients with degenerative joint disease of the hip have substantial degeneration of the lumbar spine. These patients may have back and lower extremity pain develop after THA and it may be difficult to determine whether the source of the pain is the hip or spine.

Questions/purposes: We therefore: (1) identified the incidence/prevalence of pain in the lower back in a group of patients with end-stage arthritis of the hip undergoing THA; (2) described the natural history of low back pain in this cohort undergoing THA; and (3) determined factors that were predictive of persistent low back pain after THA.

Methods: We administered a detailed questionnaire and a diagram of the human body on which the patients could draw the site of their pain, to 344 patients preoperatively, at 6 weeks, 6 months, and 1-year after THA. Before the THA, 170 patients (49.4%) reported pain localized to the lower lumbar region, whereas 174 patients did not have low back pain.

Results: Low back pain was variable in location. Postoperatively, the low back pain resolved in 113 (66.4%) of the 170 patients. Thirty-seven of the remaining 57 patients had known spine disorders. Thirty-five of the 174 patients (20%) without prior low back pain had low back pain develop within 1 year postoperatively. The low back pain improved in 17 of these 35 patients; 12 of the remaining 18 patients had preexistent spine disorders. Pain radiating below the knee was associated most closely with preexisting spine disorders.

Conclusions: Hip and spine arthritis often coexist. Most patients who presented with hip arthritis and lower lumbar pain experienced resolution or improvement of their pain after THA.

Level of evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

A flow chart shows the progress and natural history of low back pain in the cohort. The actual number of patients in each category is shown.

Fig. 2

The prevalence of low back/hip pain in the study population is shown in the flow chart. Low back pain improved in two-thirds of patients, including many with known spine disorders. One-tenth of patients without previous low back pain may have low back pain develop after the THA that can be attributed to a previously unrecognized spine disorder.