Minimally important change was estimated for the Manchester-Oxford Foot Questionnaire after foot/ankle surgery
Dawson J., Boller I., Doll H., Lavis G., Sharp R., Cooke P., Jenkinson C.
Objectives To ascertain the smallest amounts of change for the three Manchester-Oxford Foot Questionnaire (MOXFQ) domains that are likely to be clinically meaningful and beyond measurement error for conditions affecting the foot/ankle. Estimates were compared with those from the Short-Form 36 (SF-36). Study Design and Setting A prospective observational study of 671 consecutive patients undergoing foot or ankle surgery at an orthopedic hospital. Before and 9 months after surgery, patients completed the MOXFQ and SF-36; transition items (anchor) asked about perceived changes in foot/ankle pain or problems since the surgery. Results Four hundred ninety-one patients completed pre- and postoperative questionnaires. Anchor-based minimal clinically important change (MCIC) values were ∼13 points for each of the MOXFQ Walking/standing (W/S), Pain, and Social Interaction (S-I) domains [and greater than the standard error of measurement (SEM)]. MCIC values for all SF-36 domains fell within the SEM. Between-group MCIDs for the MOXFQ were W/S, 16.2; Pain, 9.9; S-I, 9.3. Distribution-based minimal detectable change (MDC 90 ) values for the MOXFQ were ∼11, ∼12, and ∼16 score points for the W/S, Pain, and S-I scales, respectively. Conclusion This article provides information for aiding the interpretability of MOXFQ outcomes data and for planning future studies. The SF-36 is not recommended as a primary outcome for foot/ankle surgery. © 2014 Published by Elsevier.