Is there an association between hip range of motion and nonspecific low back pain? A systematic review

To systematically review whether there is an association between hip range of motion (ROM) and nonspecific low back pain (NSLBP).

MEDLINE, EMBASE, Cochrane library, PsychINFO, CINAHL and AMED databases were searched from year of inception until October 31st, 2018, using a combination of LBP and hip joint search terms. Commonly cited journals were also hand searched within the previous two years.

Two reviewers independently screened identified articles, by title and abstract and then by full-text. After first round screening of 2908 identified records, 248 progressed to full-text screening. Due to the heterogeneity of studies identified, post hoc inclusion criteria of English language, studies comparing subjects with NSLBP and healthy controls, cross-sectional design, and clinical measures of hip ROM were applied. Twenty-four records were finally included.

Extracted data included population characteristics, duration and severity of NSLBP, hip movement direction, testing position, measurement tool and between-group difference. The Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was used to assess for study bias.

Hip flexion ROM was measured in seven studies, extension in 13, internal rotation (IR) in 14, external rotation (ER) in 13, abduction in six, and adduction in only two studies. Among all directions tested, IR ROM was reported in more studies as significantly reduced in NSLBP subjects compared to healthy individuals. Overall the quality of evidence was very low. Common sources of study bias included lack of sample size justification, blinding of outcome assessors, adjusting for key confounders, and poor reporting.

There is very low-quality evidence to support an association between limited hip ROM and NSLBP. Limited hip IR ROM was the only movement impairment found to be significantly associated with NSLBP, however this should be viewed with caution due to the low-quality supportive evidence. Further studies are needed.