Validity and reliability of the modified four square step test in total HIP arthroplasty

Introduction: The Modified Four Square Step Test (mFSST) evaluates dynamic stabilization by using tape instead of canes to prevent people from tripping over obstacles and losing their balance. There was no study investigating reliability and validity in primary total hip arthroplasty (THA). This study aimed to evaluate the test-retest reliability, concurrent validity, and minimum detectable change in the mFSST for individuals with primary THA.

Method: This study was cross-sectional in design. A total of 29 individuals aged 56.86 ± 10.14 years participated. The study used the test-retest method to determine the reliability of the mFSST and concurrent validity. The Timed Up and Go Test (TUGT) and Berg Balance Scale (BBS) were applied for concurrent validity. The minimum detectable change (MDC95) and the standard error measurement (SEM) were calculated.

Results: The mFSST showed excellent intra-rater reliability (ICC = 0.925). The SEM and MDC95 of the mFSST were 1.56 and 4.32. The test had a strong correlation with TUGT (r = 0.881) and BBS (r = -0.718) (p < 0.001).

Conclusion: The mFSST is a valid and reliable assessment tool that can be used for individuals with primary THA.