Purpose: Ulnar collateral ligament (UCL) avulsion fractures of thumb metacarpophalangeal joint (MCPJ) involve small
bony fragments that are usually attached to structures that are necessary for stability or movement of the joint. Satisfactory
reduction can be difficult because of the small size of the fragments. The aim of this article is to analyze outcomes of
this technique.
Methods: We used a 1.2 mm titanium hook plate in seven patients with thumb UCL avulsion fracture of MCPJ, with a
mean age of 33 years. The mean time from injury to operation was 13 days. Bone union was determined through radiographs.
Clinical outcomes were evaluated by assessing range of motion (ROM) of the thumb MCPJ, pinch strength, grip
strength, the visual analogue scale (VAS), and Korean version of the Michigan Hand Outcomes Questionnaire (K-MHQ)
score.
Results: All patients achieved bone union within 3 months and mean follow-up period was 14.3 months. The postoperative
ROM and VAS pain score improved. Grip and pinch strength were lower than the other hand but not statistically
significant. No instability was observed. In addition, postoperative K-MHQ scores showed good results. One patient underwent
hardware removal because of skin irritation and abnormal sensation. There were no other complications.
Conclusion: Mini hook plate fixation technique produced stable fixation and showed good clinical and radiologic outcomes
in avulsion fracture of thumb MCPJ.