Telemedicine-based measurement of finger joint range of motion in patients: A reliability and concurrent validity study

BACKGROUND: Although the use of telemedicine has persisted in hand surgery and therapy practices beyond the COVID-19 pandemic, there remains a need for simple, validated means of remotely measuring finger joint range of motion for integration in fast-paced virtual clinics. We propose on-screen measurement, a technique previously validated in the elbow, which involves holding a goniometer up to the telemedicine appointment screen. PURPOSE: This study aimed to determine the reliability and concurrent validity of on-screen measurements relative to the gold standard, in-person goniometry. Congruence of management plans established at virtual and in-person appointments was as a secondary aim. STUDY DESIGN: Prospective Reliability and Agreement (Concurrent Validity) Study. METHODS: Patients with Dupuytren's disease assessed virtually and in-person were recruited from one surgeon's practice. Virtual and in-person measurements in maximal passive extension, time between appointments and treatment plans made at each visit were extracted from patients' charts. In-person assessors were blinded to previous telemedicine-based measurements and, after a 2-week washout period, the original assessor and two additional assessors re-measured joints from screenshots captured at telemedicine appointment. Descriptive and statistical analyses were used to evaluate inter-rater and intra-rater reliability as well as concurrent validity. RESULTS: Fifty-four eligible patients (191 joints; 102 digits) attended telemedicine and in-person appointments at a median of 31 days apart. Inter-rater and intra-rater reliability were excellent (intraclass correlation coefficient >0.96). The absolute mean difference between on-screen and in-person measurements was 8˚, with 61.7% of on-screen measurements falling within 10˚ of in-person measurements. Management plans made at the telemedicine appointment were congruent with those carried out in-person in 96.3% of cases. CONCLUSIONS: On-screen measurement is highly reliable with concurrent validity that compares to similar photography-based measurement studies. Our results suggest on-screen measurement may be a useful tool for initial consultation and triaging of patients with flexion contractures.