Correlations Among Objectively Measured Impairment, Outcome Classification Systems, and Subjectively Perceived Disability After Flexor Tendon Repair

Abstract

Any loss of range of motion of the finger after flexor tendon repair is an impairment of function, but to what extent it causes disability is not properly understood. The aim of this study was to assess the correlation between perceived function (disability) and objectively measured loss of function (impairment), to understand what impairments are meaningful to patients. We assessed 49 patients who underwent flexor tendon repair an average of 38 months after repair. We measured the perceived function with the visual analog scale, the 4-step rating scale (poor, fair, good, or excellent), and the Disabilities of the Arm, Shoulder, and Hand (DASH) score. The objective measurement of impairment included active range of motion at each joint, total active motion, grip strength, and 2-point discrimination. We also converted range of motion into 4 categories (poor, fair, good, and excellent) following guidelines from 3 different classification systems (American Society for Surgery of the Hand, Strickland-Glocovac, and revised Strickland). We used Spearman ρ and linear regression to assess the correlation. Active range of motion at the distal interphalangeal joint had a strong correlation and total active range of motion of the finger joints had a moderate correlation with perceived function measured using the visual analog scale and DASH score. Other measured impairments did not correlate with perceived function. Objective classification categories also did not correlate with the patient's own assessment. Our results validate the use of range of motion and the DASH questionnaire in assessing flexor tendon repairs. Classification of angular measurement according to the tested systems does not reflect the patient's perspective; it limits the precision of the measurement and adds little value to the measurement itself. Prognostic IV.