Abstract

Objectives
Proximal interphalangeal joint (PIPJ) extension lag is a sequela of various finger injuries. Our aim was to document the improvement in PIPJ extension lags of fingers after using relative motion flexion (RMF) splints.
Methods
RMF splints were recommended to patients if their PIPJ extension lags were decreased with pencil test, which simulated the splint. For the eligible patients, PIPJ extension lags of the affected fingers were recorded. RMF splints were made by the therapist with a thermoplastic tape. PIPJ extension lags were measured during the control visits.
Results
There were 15 patients with a mean age of 40.8 years and mean follow-up of 8.3 weeks. The mean PIPJ extension lag degree of the affected fingers was 18.8 ± 10.1 before RMF splint application and 4.0 ± 6.0 in the last assessment.
Conclusion
We experienced that when the PIPJ extensor lag was improved with active finger extension while the MCPJ was flexed by 15°–20° (i.e., the pencil test was positive), it was worthwhile trying RMF splint as a treatment of PIPJ extensor lag. RMF splint is easy to use and patients can continue daily living activities while wearing this splint.

Key words: extension lag; pencil test; proximal interphalangeal joint; relative motion splint