Dorsal blocking orthoses for proximal interphalangeal joint volar plate injuries: A retrospective cohort study investigating the impact of joint angle on patient outcomes.

Background: Injuries to the proximal interphalangeal joint (PIPJ) of the fingers are commonly treated in hand therapy departments. Conservative management for PIPJ volar plate injuries typically involves a dorsal blocking orthosis and flexion exercises. Historically hand therapists have placed the PIPJ in varying degrees of flexion but the optimal angle is unknown.

Purpose: To compare the outcomes of two treatment groups who received dorsal blocking orthoses: Those who the orthosis was positioned in neutral compared to those in 25-30° of flexion.

Study design: Retrospective cohort study.

Method: Patients treated by the hand therapy service at a major metropolitan hospital network in Melbourne, Australia, for conservative management of a PIPJ volar plate injury over a three-year period were included in our study. Data regarding patient demographics, digits affected and injury type were collected. Outcomes included presence of a fixed flexion deformity (FFD), amount of hand therapy received and total active flexion at the PIPJ.

Results: One hundred and eleven participants were included in our study. The mean age was 26 and 59 (53%) were males. Seventy two (64%) participants received a dorsal blocking orthosis positioned in neutral and 39 (35%) were positioned in 25-30° flexion at the PIPJ. Participants whose orthosis was positioned at 25-30° had an average of 24 more minutes in hand therapy (which equates to approximately one appointment) compared to those whose PIPJ was positioned in neutral (p=0.006, d=0.5). Eight percent less participants developed a FFD (p = 0.24) and 13% more participants achieved full flexion (p = 0.06) in the group who received a dorsal blocking orthosis in neutral, however these results were not statistically significant.

Conclusion: PIPJ volar plate injures treated in an orthosis positioned in neutral required fewer hand therapy appointments. There was no statistically significant difference between groups regarding development of a FFD or full flexion.