Split hamate fractures as part of complex ulnar carpometacarpal injuries: radiographic and functional outcomes

BACKGROUND: Split hamate fractures, which most often are a complicating part of fracture dislocations of the 5th or 5th and 4th carpometacarpal joints, are rare and challenging injuries that can severely affect hand function. The injury usually requires surgical treatment. However, both short- and long-term data on the effectiveness of these interventions are limited. The objective of this study is to advance understanding of this rare hand surgical condition by investigating its epidemiology, etiopathogenesis, subsequent complications, and functional outcomes. METHODS: Between 2010 and 2024, a total of 29 patients with a split hamate fracture were treated at a level-1 trauma center, of which 12 patients are included in this study. Using patient surveys (DASH, SF-36, PRWE), along with clinical and radiological examinations, the hand function of a total of 12 patients with split hamate fractures is evaluated. RESULTS: Twelve male patients with a split hamate fracture were included, with a mean age of 28.1 years at the time of surgery. In 10 patients (83%) the dominant right hand was affected, most involving, the injuries resulted from direct trauma or a fall; surgery was performed on average of 12 days after injury. Functional outcomes were favourable, with a mean DASH score of 14.1 and PRWE score of 14.8, indicating minimal residual reduction of function in most cases. Radiological follow-up showed complete fracture consolidation in 92% of patients, while degenerative changes and implant-related findings were observed in 58% and 42% of cases, respectively. CONCLUSION: This case series demonstrates that split hamate fracture can achieve excellent functional and radiological outcomes with surgical treatment, while also highlighting specific challenges in surgical approach and osteosynthesis.