Validation of a new instrument for evaluating low back pain in the young athlete.

OBJECTIVE To validate a back-specific instrument for functional assessment in the young athlete for clinical and research purposes, the Micheli Functional Scale (MFS). DESIGN Prospective cohort study, Diagnostic Level II. SETTING Division of Sports Medicine Clinic, Children's Hospital Boston. PARTICIPANTS Male and female patients aged 12 to 22 with and without low back pain. INTERVENTIONS Patients presenting with back pain were compared with a control group of patients presenting with complaints other than back pain. Both groups were given the modified Oswestry Low Back Pain Disability Questionnaire (ODQ) and MFS. MAIN OUTCOME MEASURES Micheli Functional Scale and ODQ score correlations. RESULTS A total of 94 patients were enrolled (44 patients with low back pain and 50 patients without low back pain). Ages ranged from 12 to 22 for both groups, with no differences in age (P = 0.07) or gender (P = 0.50). Patients with back pain had significantly higher ODQ scores (median, 32 points) and MFS scores (median, 47 points) compared with controls (median, 0 points; P < 0.0001). These results held for male and female patients and younger (12-16.99 years) and older (17-22 years) age groups. The Pearson correlation coefficient showed a high positive correlation between MFS scores and ODQ scores (Pearson r = 0.90, P < 0.0001). Cronbach level indicated excellent item reliability on the MFS (α = 0.904, P < 0.0001). CONCLUSIONS The MFS is a valid instrument for assessing pain and functional levels in the young athlete. This scale considers pain, athletic function, and athletic disability.