Night-time immobilization of the distal interphalangeal joint reduces pain and extension deformity in hand osteoarthritis

Abstract

Objective: DIP joint OA is common but has few cost-effective, evidence-based interventions. Pain and deformity [radial or ulnar deviation of the joint or loss of full extension (extension lag)] frequently lead to functional and cosmetic issues. We investigated whether splinting the DIP joint would improve pain, function and deformity.

Methods: A prospective, radiologist-blinded, non-randomized, internally controlled trial of custom splinting of the DIP joint was carried out. Twenty-six subjects with painful, deforming DIP joint hand OA gave written, informed consent. One intervention joint and one control joint were nominated. A custom gutter splint was worn nightly for 3 months on the intervention joint, with clinical and radiological assessment at baseline, 3 and 6 months. Differences in the change were compared by the Wilcoxon signed rank test.

Results: The median average pain at baseline was similar in the intervention (6/10) and control joints (5/10). Average pain (primary outcome measure) and worst pain in the intervention joint were significantly lower at 3 months compared with baseline (P = 0.002, P = 0.02). Differences between intervention and control joint average pain reached significance at 6 months (P = 0.049). Extension lag deformity was significantly improved in intervention joints at 3 months and in splinted joints compared with matched contralateral joints (P = 0.016).

Conclusion: Short-term night-time DIP joint splinting is a safe, simple treatment modality that reduces DIP joint pain and improves extension of the digit, and does not appear to give rise to non-compliance, increased stiffness or joint restriction.

Trial registration: clinical trials.gov, http://clinicaltrials.gov, NCT01249391.

Keywords: distal; interphalangeal; non-pharmacological therapy; osteoarthritis; pain; splint.

Fig. 1

Custom thermoplastic gutter splinting of the DIP joint (A) An example of an extension lag deformity of the distal IP joint prior to splinting. There is incomplete extension at the joint on attempted active extension by the individual. (B) Splints were fabricated from thermoplastic by a senior hand therapist and adjusted at 6 weeks if necessary to ensure comfort and fit. An example is shown. (C) Anteroposterior plain radiograph of a digit from a study subject showing an affected middle finger DIP joint on the right hand. Evidence of radiographic change consistent with OA of the joint is present and there is also radial deviation deformity.

Fig. 2

Reduction in pain in DIP joints by splinting For each subject number (pnos), patient-reported pain scores in the intervention joint (int) and control joint (cont) were recorded by a numerical rating scale (0–10). (A and D) The change in pain scores in the intervention joint at 3 months: the pain at baseline is subtracted from the pain at 3 months. A negative value suggests an improvement in pain. (A) The change in average pain in the intervention joint at 3 months (primary outcome) (P = 0.002). (B) Summary of the median change in average pain from baseline to 3 and 6 months (*P = 0.049). (C) The difference in average pain between the intervention and control joints at 6 months is shown for all participants. A negative value suggests more improvement in the intervention joint than the control joint (P = 0.049). (D) The change in average pain in the intervention joint at 3 months is shown in a predefined subgroup (n = 9) with a perfect match control joint on the opposite hand (P = 0.035).

Fig. 3

Improvement in extension lag deformity in DIP joints by splinting For each subject number (pnos), the degrees of incomplete extension on attempted active extension (ext lag) were recorded for the intervention joint and control joint. A positive value suggests an improvement in deformity and a negative value suggests a deterioration. (A) The change in extension lag deformity in the intervention joint at 3 months. The lag at baseline is subtracted from the lag at 3 months (P = 0.096). (B) Summary of median change in extension lag deformity from baseline to 3 and 6 months. *P = 0.039 in intervention joints only. (C) The change in extension lag deformity at 3 months in control joints (clear circles) and in intervention joints (black circles) in a predefined subgroup with a perfect match control on the opposite hand (n = 9; P = 0.016).