Objectives

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 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.

The responsiveness of the Manchester–Oxford Foot Questionnaire (MOXFQ) was compared with foot/ankle-specific and generic outcome measures used to assess all surgery of the foot and ankle. We recruited 671 consecutive adult patients awaiting foot or ankle surgery, of whom 427 (63.6%) were female, with a mean age of 52.8 years (18 to 89). They independently completed the MOXFQ, Short-Form 36 (SF-36) and EuroQol (EQ-5D) questionnaires pre-operatively and at a mean of nine months (3.8 to 14.4) post-operatively. Foot/ankle surgeons assessed American Orthopaedic Foot and Ankle Society (AOFAS) scores corresponding to four foot/ankle regions. A transition item measured perceived changes in foot/ankle problems post-surgery. Of 628 eligible patients proceeding to surgery, 491 (78%) completed questionnaires and 262 (42%) received clinical assessments both pre- and post-operatively. The regions receiving surgery were: multiple/whole foot in eight (1.3%), ankle/hindfoot in 292 (46.5%), mid-foot in 21 (3.3%), hallux in 196 (31.2%), and lesser toes in 111 (17.7%). Foot/ankle-specific MOXFQ, AOFAS and EQ-5D domains produced larger effect sizes (> 0.8) than any SF-36 domains, suggesting superior responsiveness. In analyses that anchored change in scores and effect sizes to patients’ responses to a transition item about their foot/ankle problems, the MOXFQ performed well. The SF-36 and EQ-5D performed poorly. Similar analyses, conducted within foot-region based sub-groups of patients, found that the responsiveness of the MOXFQ was good compared with the AOFAS.

This evidence supports the MOXFQ’s suitability for assessing all foot and ankle surgery.