ORIGINAL ARTICLE Single Blind, Prospective, Randomized Controlled Trial Comparing Dorsal Aluminum and Custom Thermoplastic Splints to Stack Splint for Acute Mallet Finger Lisa J. O’Brien, MClinSc, BAppSc(OT), Michael J. Bailey, PhD, MSc ABSTRACT. O’Brien LJ, Bailey MJ. Single blind prospec- tive, randomized controlled trial comparing dorsal aluminum and custom thermoplastic splints to stack splint for acute mallet finger. Arch Phys Med Rehabil 2011;92:191-8. Objective: To compare Stack, dorsal, and custom splinting techniques in people with acute type 1a or b mallet finger. Design: Multi-center randomized controlled trial. Setting: Outpatient hand therapy clinics (2 public hospitals and 1 private clinic). Participants: Patients (N=64) with acute type 1a or b mallet finger. Interventions: Prefabricated Stack splint (control), dorsal padded aluminum splint, or custom-made thermoplastic thim- ble splint. All were worn for 8 weeks continuously, with a 4 week graduated withdrawal and exercise program. Main Outcome Measures: The primary outcome was ex- tensor lag at 12 and 20 weeks. Secondary outcomes were incidence of treatment failure, complications, range of motion of the distal interphalangeal joint, pain (visual analog scale) patient compliance, and patient satisfaction. Results: There was no difference in the primary outcome between groups at 12 or 20 weeks; however, the Stack and dorsal splints had significant rates of treatment failure (23.8% in both groups, compared to none in the thermoplastic group; P=.04). There was a medium negative correlation between patient compliance and degree of extensor lag. No significant differences between groups were observed for patient satisfac- tion or pain. Conclusions: As splints for mallet finger must be worn continuously for 6 to 8 weeks, and compliance correlates with favorable outcomes, treating practitioners must ensure the splint provided is robust enough for daily living requirements and does not cause complications, which are intolerable to the patient. In this study, no extensor lag difference was found between the 3 splint types, but custom-made thermoplastic splints were significantly less likely to result in treatment failure. Key Words: Finger injuries; Orthotic devices; Rehabilita- tion; Splints; Tendons. © 2011 by the American Congress of Rehabilitation Medicine M ALLET FINGER, A LOSS OF continuity of the distal insertion of the extensor tendon at the finger tip, is a common hand injury in ball sports, 1 but can also occur from minor incidents such as bed-making and trips/falls. 2 If not managed correctly, the patient can be left with a persistent extension lag and swan neck deformity (flexion deformity of DIPJ with a secondary hyperextension deformity of the prox- imal joint resulting from an imbalance in the extensor mecha- nism). Other persistent problems associated with mallet finger include cold sensitivity 3,4 and chronic pain, 3-5 although these are relatively uncommon. Conservative treatment is the pri- mary choice for a typical mallet finger injury, 6 which is a closed injury with or without a small (20% of joint surface) bony avulsion fragment. These injuries are classified as Doyle type 1a (no bone injury, but loss of extensor tendon continuity) or 1b (small bony avulsion of terminal extensor tendon without DIPJ subluxation). 7 Treatment involves static splinting in full extension to slight hyperextension to allow relaxation of the tendon and encourage healing by bringing the torn ends or fracture fragments closer together during the healing phase. The technique adopted during splinting is regarded as very important because over-zealous hyperextension can lead to restriction of circulation and impaired healing or even skin necrosis. 8,9 Identifying a superior splint would improve the management of these injuries, and a recently published well designed RCT found a trend in favor of the custom thermoplastic splint (compared to dorsal or volar padded aluminum splints) for resolving extensor lag, although this was not statistically sig- nificant. 10 A Cochrane review (updated in 2008) 6 also found insufficient evidence to establish the comparative effectiveness of different types of finger splints (either custom-made or off-the-shelf) concluding that “until there is reliable evidence to the contrary, the continued use of the off-the-shelf but suitably fitted Stack mallet splint, or equivalent, for the major- ity of patients (ie, those with acute closed soft-tissue or bony mallet finger injury) seems appropriate.” (6p8) It is worth noting that only 4 trials met the review’s inclusion criteria for research design, and all of these were “small, heterogeneous, inade- quately described and reported . . . and had methodological From the Departments of Occupational Therapy (O’Brien) and Biostatistics (Bai- ley), the Alfred Hospital, Melbourne, Victoria, Australia; and the Departments of Occupational Therapy (O’Brien) and Epidemiology and Preventive Medicine (Bai- ley), Monash University, Melbourne, Victoria, Australia. Presented to the International Federation of Societies for Hand Therapists, March 11–15 2007, Sydney, Australia. Supported by The Alfred Allied Health Research Grant (grant no. A10602). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organi- zation with which the authors are associated. The trial was registered with the U.S. National Library of Medicine and the Australian Clinical Trials Registry (trial nos. NCT00310570 and NO12606000123549, respectively). Reprint requests to Lisa J. O’Brien, MClinSc, BAppSc(OT), Monash University, PO Box 527, Frankston, VIC 3199 Australia, e-mail: lisa.obrien@ med.monash.edu.au. 0003-9993/11/9202-00647$36.00/0 doi:10.1016/j.apmr.2010.10.035 List of Abbreviations ANOVA analysis of variance DIPJ distal interphalangeal joint ITT intention-to-treat RCT randomized controlled trial VAS visual analog scale 191 Arch Phys Med Rehabil Vol 92, February 2011