The MOXFQ patient-reported questionnaire: assessment of data quality, reliability and validity in relation to foot and ankle surgery.
Dawson J., Boller I., Doll H., Lavis G., Sharp R., Cooke P., Jenkinson C.
Previously validated for hallux valgus surgery, the Manchester-Oxford Foot Questionnaire (MOXFQ) is here evaluated for use with different regions of the foot and ankle. The study recruited 671 consecutive patients (87.8% of those eligible), mean age 52.8 years, 64% female, who completed the MOXFQ and SF-36 general health survey before foot or ankle surgery. Surgeons completed the American Orthopaedic Foot & Ankle Society (AOFAS) scales and indicated that the patients' main regions for surgery were: Hallux 210 (31.3%), Lesser toes 119 (17.7%), Mid foot 22 (3.3%), Ankle/hind foot 311 (46.3%), Multiple/whole foot 9 (1.3%). Individual MOXFQ items were assessed in terms of response rate and floor/ceiling effects, with the validity of the three MOXFQ scales (Walking/standing, Pain, and Social interaction) being assessed in terms of item-total correlations, internal and test-retest reliability, and construct validity. MOXFQ item response rates were high (all >98%). Cronbach's alphas of >0.7 confirmed internal consistency of all three scales. Test-retest ICCs were all ≥0.89. Correlations of >0.4 obtained with related SF-36 and AOFAS scales supported a priori hypotheses. Good measurement properties are confirmed for the MOXFQ in the context of baseline assessment of patients receiving surgery for a variety of foot or ankle problems.