Acquired trigger thumb is common in children. The exact etiology remains unknown. A child usually presents with a snapping phenomena of the IP joint or fixed flexion deformity. The exact incidence of spontaneous resolution is variable ranging from 24% to 50%. In general, resolution rates decrease as the child ages. The purpose of this study is to determine the efficacy of splint therapy as compared to observation.
Fifty children completed the study with 62 reducible trigger thumbs. The mean age ranged from 2 months to 4 years with an average of 1 year and 11 months. Children’s thumbs that could be reduced passively to full extension by gentle manipulation were placed into a splinting group or observation group. The choice depended on the parent’s decision after a detailed explanation of the diagnosis. A simple thermoplastic splint was fabricated that maintained the thumb and MP joint in full extension and IP joint in hyperextension. Wearing instructions were all day long for 6 to 12 weeks and changed to night splinting to prevent recurrence. As the flexion contracture reoccurred, splinting was returned to a whole day for an additional 4 weeks. Splinting time varied but was approximately three months. The outcome was classified as cured, improved, or non-improved. Cure was defined as full range of motion without snapping. Improved was defined as full range of motion with occasional snapping less than one episode per week and non-improved was defined as persistent or recurrent flexion contracture or requiring a surgical intervention.
Of the 55 children, 20 were treated with extension splinting and 27 were observed. In the splinting group, there were 12 cured thumbs, 10 improved thumbs, and 9 non-improved thumbs. In comparison, the observed group showed 4 cured, 3 improved and 24 non-improved thumbs. A difference between the groups was significant. The splinting group had a 71% response rate as defined as cured or improved. In contrast, only 23% of the observed group were cured or improved. The only complication of splint therapy was a contact dermatitis. No iatrogenic deformities were noted.
Surgery for a trigger thumb is simple and effective. However, surgery is not without complications. This study revealed that nonoperative treatment in reducible thumbs may result in considerable improvement 70% of the time. In addition, failure to respond to conservative management could still be treated with surgery. These results must be taken with some caution as no child older than 3 years of age had a “cured” outcome. Therefore, splinting can be attempted in children pending surgery less than 3 years of age. However, routine practice is to recommend primary release the first annular pulley in children older than 3 years of age.
Trigger, Thumb, Pediatric, Splint
J Pediatr Orthop