Test‐Retest Reliability of Dynamic Balance Performance‐Based Measures Among Adults With a Unilateral Lower‐Limb Amputation

Background There is large variation in administration of performance‐based, dynamic balance measures among adults with lower‐limb amputation (LLA). Further, there has been limited exploration of test‐retest reliability of these measures in adults with lower‐limb loss, including whether there is a difference in reliability if one records “best” vs “average” performance across trials. Objective To determine test‐retest reliability of several balance tests for both “best” and “average” score performance in community‐dwelling adults with a unilateral LLA, including quantification of the precision of individual scores (SE of the measurement, SEM) and estimates of minimal detectable change (MDC90). Design Cross‐sectional study. Setting Mobile research laboratory. Participants 27 participants (55.5% female) with an average age of 51 (SD = 12.2) years, who were predominantly community‐ambulators (92.5%), after a unilateral transtibial (n = 20), transfemoral (n = 5), or other major lower‐extremity (n = 2) amputation, were included. Median time since amputation was 6.3 (2.3, 19 [25th, 75th interquartile range]) years. Methods Reliability was evaluated using intraclass correlation coefficient (ICC) models (3,1 or 3,k). SEMs and MDC90 values with 95% confidence intervals (CIs) were calculated. Main Outcome Measures 360o Turn Test, 5 Times Sit‐To‐Stand, Functional Reach Test, Figure‐of‐8 Walk Test, and Four Square Step Test (FSST). Results The ICCs (3,1 or 3,k) for all tests (for both “best” and “average” performance) were considered good‐to‐excellent and CIs varied from 0.69 (95% CI = 0.40‐0.85) to 0.97 (95% CI = 0.95‐0.99). For most tests, “best” and “average” performance demonstrated similar ICC values. MDC90 values did not surpass 10% of test means for any of the measures. Conclusions The dynamic balance measures evaluated for use among community‐dwelling adults with a unilateral LLA demonstrated excellent reliability, along with high precision of scores and MDC values that did not exceed 10% of testing means. Either best or average scoring may be used when administering the majority of these tests, as long as the assessment method is appropriately documented and replicated at follow‐up to allow direct comparisons. With the FSST, clinicians should consider taking the average of two FSST trials. Level of Evidence III