The Manchester–Oxford Foot Questionnaire (MOXFQ) is a validated
16-item, patient-reported outcome measure for evaluating outcomes
of foot or ankle surgery. The original development of the instrument
identified three domains. This present study examined whether the
three domains could legitimately be summed to provide a single summary
index score. The MOXFQ and Short-Form (SF)-36 were administered to 671 patients
before surgery of the foot or ankle. Data from the three domains
of the MOXFQ (pain, walking/standing and social interaction) were
subjected to higher order factor analysis. Reliability and validity
of the summary index score was assessed.Objectives
Methods
The patient-reported Manchester-Oxford Foot Questionnaire (MOXFQ), with 3 dimensions (Walking/standing(W/S), Pain, Social interaction(SI)) has previously been validated in patients undergoing hallux valgus surgery. A preliminary cross-sectional evaluation of its measurement properties relating to surgery on different regions of the foot and ankle is presented here. Within 4 weeks prior to foot or ankle surgery, 671of 764 consecutive eligible patients (87.8% response rate) were assessed with the: (i) MOXFQ questionnaire, (ii) SF-36 general health survey (iii) American Orthopaedic Foot & Ankle Society (AOFAS) scales. Sample characteristics: mean age 53 years 427 (63.6%) female. Patients were booked for (main) surgery on Hallux (210, 31.3%), Lesser Toes (119, 17.7%), Mid foot (22, 3.3%), Ankle/Hind foot (311, 46.3%) and whole foot/multiple regions (9, 1.3%) MOXFQ item response rates were high (<2% missing on any one item) with responses generally well distributed across response categories. Item-total correlations within each dimension were generally above recommended levels. Internal consistency, as assessed by Cronbach's alpha, were 0.93, 0.84 and 0.71 for the W/S, Pain and SI dimensions, respectively. Within Hallux, Lesser toes and Ankle/hind foot surgical subgroups (low numbers precluded mid foot and whole/multiple region analyses), alphas for these subscales were similar. Convergent validity of MOXFQ was demonstrated by correlations between the 3 dimensions (W/S, Pain, SI) with similar dimensions of the SF-36 and relevant AOFAS scales. A priori hypotheses were generally supported. The MOXFQ demonstrates good baseline measurement properties in patients undergoing a range of foot and ankle surgery, suggesting its suitability as an outcome measure for clinical trials of foot and ankle surgery in general. The SI dimension, concerned with cosmesis and social participation has somewhat weaker properties but remains useful. Evidence for the MOXFQ's responsiveness across the range of foot and ankle surgery is yet to be assessed.
