Minimal Clinically Important Difference of the Four Square Step Test in people with Degenerative Spinal Conditions

Abstract Objective To identify the minimal clinically important difference (MCID) in the Four Square Step Test (FSST) for patients with degenerative spinal conditions before and after a six-week group-based physiotherapy programme. Design Secondary analysis of a longitudinal cohort study Setting Physiotherapy department within a specialised orthopaedic hospital in the UK Participants Men and women with degenerative spinal conditions Interventions All participants had a routine care package of up to six group-based physiotherapy led exercise and education sessions. Main outcome measures An anchor-based approach using a self-report outcome measure (Activities-specific Balance Confidence [ABC] Scale) was utilised as a comparator to determine the MCID of the FSST. The MCID for the FSST was calculated as the difference in mean change scores from those who improved on the ABC Scale against those who did not improve (based on the standard error of measurement of the ABC Scale). Results Twenty-eight participants with degenerative spinal conditions (19 female) had a mean age of 73years (SD 7.7). The mean ABC Scale scores for the whole sample were 61% (SD 19.1) at baseline and 66% (SD 18.3) post-physiotherapy. The mean FSST scores for the whole sample were 19.1s (SD 9.8) at baseline and 13.9s (SD 6.3) post-physiotherapy. The MCID for the FSST was 3.6 seconds. Conclusions The MCID for improvement in balance was 3.6 seconds, indicating people with degenerative spinal conditions are likely to perceive an improvement of ≥ 3.6 seconds in their FSST score as an important change in their balance performance and confidence.