Management of stable proximal interphalangeal joint volar plate injuries with figure-of-8 orthoses: A parallel-group randomized controlled trial

Background

Volar plate injuries of the proximal interphalangeal (PIP) finger joint are common. Conservative treatment involves orthoses to limit hyperextension at the PIP joint yet allow movement of the joints to prevent joint stiffness and deformity. Custom-made dorsal blocking orthoses are recommended treatments. Previous research also supports the use of a figure-of-8 orthosis, although the comparative effectiveness of these orthoses is not currently known.

Purpose

This study aimed to compare the figure-of-8 orthosis and dorsal blocking orthosis for changes in the range of movement, pain, and function following stable volar plate PIP joint injuries and to compare the number of hand therapy appointments required.

Study Design

A parallel-group pilot randomized controlled trial. This trial was registered with the Australian and New Zealand Clinical Trials Registry (Trial ID: CTRN12619000449134).

Methods

Participants aged 13-65 years were recruited from an outpatient hand therapy service and randomly assigned to experimental or control groups. The experimental group of 20 participants received a custom-made thermoplastic figure-of-8 orthosis limiting the extension to 15-20 degrees. The control group of 22 participants had a dorsal blocking orthosis, which was serially extended by 10 degrees weekly starting at 30 degrees flexion. Participants were blinded to their group allocation. Outcome measures included range of movement, edema, pain, function, and number of hand therapy appointments. Data collection was completed by the treating therapist who was not blinded to group assignment. Data analysis included a series of mixed-model analyses of variance to examine changes over time.

Results

Forty-two participants were recruited and had their data analyzed. No significant between-group differences were observed for DIP flexion, PIP flexion, pain, and function from baseline to follow-up. Both groups exhibited significant improvements in these outcomes over time (p < 0.001); effect sizes ranged from small to large (0.28-0.79). On average, the intervention group required 4 (±1.5) appointments compared to 6 (±1.5) in the control group over the same period representing a significant difference (p < 0.001).

Conclusions

Both dorsal blocking and figure-of-8 orthoses provide similar outcomes. The use of a figure-of-8 orthosis, or a dorsal block orthosis fabricated in maximal comfortable extension depending on severity, could reduce the number of appointments and increase convenience for patients.