The minimal clinically important difference (MCID) of the Olerud Molander Ankle Score (OMAS) in patients with unstable ankle fracture

Abstract

Introduction The Olerud Molander Ankle Score (OMAS) is a widely used validated Patient Reported Outcome Measure (PROM). For clinical research, it is important to determine the Minimal Clinically Important Difference (MCID). The objective of this study was to determine the MCID of the OMAS at several moments in the follow-up, in a cohort of patients that underwent open reduction and internal fixation of unstable ankle fractures with syndesmotic injury. Materials and methods Data for this descriptive study were extracted from a prospective randomized controlled trial, the RODEO trial. The Dutch version of the OMAS was completed at 3, 6 and 12-month follow-up and estimated at baseline. The used anchor-based methods were: mean change and ROC curve. The distribution-based methods were: 0.5SD and minimal detectable change (MDC). Results This cohort included 148 patients. The mean OMAS score in the group with minimal improvement between 3 and 6 months was 15.0 (SD 17.5, 95%CI 9.4–20.6) and between 6 and 12 months 9.5 (SD 17.1, 95% CI 3.1–15.9). The ROC curve between 3 and 6 months resulted in a MCID of 12.5 (AUC 0.72) and between 6 and 12 months, the MCID was 7.5 (AUC 0.78). Using 0.5 SD, the MCID was 10.52 (SD 21.04) at 3 months, 11.37 (SD 22.73) at 6 months and 10.47 (SD 20.94) at 12 months. The MDC was 4.72 at 3 months, 5.20 at 6 months and 4.71 at 12 months. Conclusions The calculated MCID in patients following surgery for unstable ankle fractures ranges from 10.5 to 15.0 at 3–6-month follow-up and from 7.5 to 11.4 at 6–12-month follow-up, depending on moment and method.

Arthroscopically assisted versus open reduction internal fixation for ankle fractures: a systematic review and meta-analysis

“…3 A). The calculated MCID of OMA score in patients following ankle fractures determined to be between 10.5 and 15.0 [ 22 ]. However, the smallest treatment effect of OMA score (6.6) was below the MCID (10.5), suggesting that while the improvement was statistically significant, it may not have a significant clinical impact.…”

“…The MCID represents the smallest change in a patient's condition or health outcome that is considered to be meaningful and important from a clinical perspective [ 17 ]. It is often used as a benchmark for evaluating the effectiveness of a medical treatment or intervention, as well as for determining whether a change in a patient's condition is significant enough to warrant a change in treatment [ 22 ]. By comparing the pooled results with the MCID, we aimed to gain a clearer understanding of the clinical significance of our findings.…”

“…OMA score is a validated clinical scoring system used to evaluate the severity of ankle fractures [ 28 ]. Penning et al conducted a cohort study to determine the MCID of the OMA score for patients with ankle fractures that underwent surgeries, reporting that the calculated MCID for OMA score ranges from 10.5 to 15.0 [ 22 ]. Ankle arthroscopy was not found to improve OMA score in a retrospective study by Fuchs et al that compared ankle ORIF with and without ankle arthroscopy [ 18 ].…”

Operative vs Nonoperative Management of Unstable Medial Malleolus Fractures

“…Since trial completion, MCID values for the OMAS after ankle fracture have been published, ranging from 4.3 to 11.4, influenced by timing and method of calculation after injury. [38][39][40] A difference of 7.5 points in the current trial may therefore be viewed as clinically significant dependent on which MCID value is referenced. The results collected were from a single center and therefore may not represent general orthopedic practice, although patient care was supervised by 12 orthopedic trauma surgeons and followed a pragmatic approach.…”

Functional outcome of routine versus on-demand removal of the syndesmotic screw

“…8 At 12 months of follow-up, the OMAS has a minimal clinical important difference (MCID) ranging from 7.5 to 10.5 and a minimal detectable change (MDC) of 4.7. 17 The AOFAS is a PROM that includes nine items and can be divided into three subscales (pain, function and alignment). 9 The AOFAS accumulates to a total score ranging from 0 points (indicating severe pain and impairment) to 100 points (no symptoms or impairment).…”