Comparison of two relative motion extension approaches (RME with versus without an additional overnight orthosis) following zones V-VI extensor tendon repairs: A randomized equivalence trial

Study design: Multi–center randomized controlled trial with two intervention parallel groups. An equivalence trial.
Introduction: Relative motion extension (RME) orthoses are widely used in the postoperative management
of finger extensor tendon repairs in zones V-VI. Variability in orthotic additions to the RME only (without
a wrist orthosis) approach has not been verified in clinical studies.
Purpose of the study: To examine if two RME only approaches (with or without an additional overnight
wrist-hand-finger orthosis) yields clinically similar outcomes.
Methods: Thirty-two adult (>18 years) participants (25 males, 7 females) were randomized to one of
two intervention groups receiving either 1) a relative motion extension orthosis for day wear and an
overnight wrist-hand-finger orthosis (’RME Day’ group), or 2) a relative motion extension orthosis to be
worn continuously (’RME 24-Hr’ group); both groups for a period of four postoperative weeks.
Results: Using a series of linear mixed models we found no differences between the intervention groups
for the primary (ROM including TAM, TAM as a percentage of the contralateral side [%TAM], and Millers
Criteria) and secondary outcome measures of grip strength, QuickDASH and PRWHE scores. The models
did identify several covariates that are correlated with outcome measures. The covariate ‘Age’ influenced
TAM (P = .006) and %TAM (P = .007), with increasing age correlating with less TAM and recovery of TAM
compared to the contralateral digit. ’Sex’ and ’Contralateral TAM’ are also significant covariates for some
outcomes.
Discussion: With similar outcomes between both intervention groups, the decision to include an additional night orthosis should be individually tailored for patients rather than protocol-based. As the covariates of ‘Age’ and ‘Sex’ influenced outcomes, these should be considered in clinical practice.