Reliability, validity and responsiveness of composite finger flexion in patients with traumatic hand injuries: A clinical measurement study.

Background: Composite finger flexion (CFF) is proposed to be a convenient alternative to total active motion (TAM) and total passive motion (TPM). Passive CFF (PCFF) may be useful for early monitoring in post-operative rehabilitation of traumatic hand injuries.

Purpose: To determine whether active and passive CFF are reliable, valid, and responsive measures of hand motion and of higher utility to the tester.

Study design: Cross-sectional observational clinical measurement study.

Methods: Fifty hand injury patients were recruited from a hospital-based out-patient clinic. TAM, TPM, repeated measures of active CFF (ACFF) and PCFF, self-reported stiffness, patient reported wrist/hand evaluation (PRWHE) scores, and grip strength were recorded. Intraclass correlation coefficients (ICCs) and standard error of measurement were calculated for inter-rater and test-retest reliability. Criterion and construct validity were assessed using correlation coefficients. Responsiveness was explored by calculating correlation coefficients of change scores, effect sizes, and standardized response means. Time taken to measure CFF and TAM/TPM was recorded to consider utility.

Results: The average age of participants was 47 years and 36% were female. Inter-rater and test-retest reliability estimates for ACFF and PCFF were excellent (ICCs = 0.95-98). Standard error of measurement values ranged from 0.21 to 0.33. The correlation coefficient for criterion validity between ACFF and TAM was -0.69; PCFF and TPM was -0.65; and ACFF and PCFF was 0.83. For construct validity, ACFF and TAM were similarly correlated with PRWHE. Correlations between changes in stiffness with ACFF and PCFF were 0.43 and 0.26, respectively. Effect sizes of ACFF and PCFF were small at 0.1 and 0.2. Time taken to measure CFF was much shorter than TAM/TPM.

Conclusions: The results of this study support the use of active and passive CFF as a reliable, valid, and efficient tool in the clinical setting. Further study is required to verify the responsiveness of CFF.