Intermittent vs continuous treatment of flexion contractures of the proximal interphalangeal joint

Stiffness of the proximal interphalangeal joint is a common and disabling condition often managed conservatively with orthoses applying low-load prolonged stretch. The key therapeutic variable in these interventions is Total End Range Time, but the clinical impact of the initial orthotic regimen (continuous vs intermittent) remains unclear.

To compare the efficacy of an early continuous high-dose (20-22 h/day) regimen vs an initial intermittent low-dose (10-14 h/day) regimen-later escalated to high-dose-in improving passive extension of the proximal interphalangeal joint in patients with joint stiffness using an elastic tension digital neoprene orthosis.

Fifty patients (57 affected proximal interphalangeal joint) were randomized to group A (continuous high-dose) or group B (intermittent low-dose, converted to high-dose after week 3). Passive range of motion was measured goniometrically at baseline, week 1, week 3, and final follow-up. Treatment compliance and patient-reported discomfort were also assessed.

At week 1, group A showed significantly greater passive range of motion improvement than group B (18.6° ± 6.97 vs 12.6° ± 5.23; p < 0.001; Cohen's d: 0.87). Although group B switched to the continuous regimen after week 3, it never reached the levels of improvement achieved by group A at any follow-up. Effect sizes remained large at week 3 and final follow-up, consistently favoring the early continuous regimen. The continuous protocol was also better tolerated during initial adaptation.

Early initiation of a continuous high-dose orthotic regimen yields superior short- and long-term recovery of proximal interphalangeal joint extension compared to starting with an intermittent protocol, even if the regimen is intensified later. Delayed optimization of Total End Range Time does not compensate for early treatment deficits. These findings emphasize the importance of maximizing Total End Range Time from the outset in conservative management of proximal interphalangeal joint flexion contractures.