A Single-Blind Pilot Study to Determine Risk and Association Between Navicular Drop, Calcaneal Eversion, and Low Back Pain

ObjectiveSyndromes causing mechanical low back pain (MLBP) continue to plague the US health care system. One hypothesis is that flatfeet are a risk factor for MLBP. This pilot study evaluated whether subjects with flatter feet are at greater risk for MLBP than subjects without flatter feet.MethodsFifty-eight subjects (16-70 years old) were allocated to a group diagnosed with 2 or more episodes of MLBP or with no history of MLBP. A blind assessor measured navicular drop (ND) using navicular height (NH) and calcaneal eversion (CE). Based on a range of reported data, flatfoot was defined as a possible risk factor for MLBP with ND greater than 3, 8, and/or 10 mm, and/or greater than 6° CE.ResultsAccording to χ2 analysis, risk of MLBP appeared similar between groups (P > .05). There was no significant difference (P > .05) between continuous variables (t tests, Pearson r and r2) with one exception, correlation of increasing CE with increasing ND (P = .0001). Power was generally low (<0.80). Likelihood ratios and Fisher exact tests supported the χ2 analysis.ConclusionsIn this study, flatfeet did not appear to be a risk factor in subjects with MLBP. However, small sample size, low power, broader age range, low prevalence of flatfeet (>10 mm ND), and lesser back pain severity make these data tentative. Further research is needed.