[Ulnar carpometacarpal joint fracture luxation of fourth and fifth ray]

Carpometacarpal fracture dislocations of the ulnar rays are rare but complex injuries of the hand and frequently pose a significant diagnostic and therapeutic challenge.

Epidemiologically, affected patients are predominantly young males, with a high proportion of injuries resulting from punching mechanisms. Owing to the often unspecific clinical presentation and difficult visualization in conventional radiographs, there is a substantial risk of delayed diagnosis and treatment, which appears to be associated with inferior clinical outcomes. Early CT scans in cases of suspected injury are therefore considered essential.

In addition to the consistent involvement of the fifth metacarpal (MC V), the fourth metacarpal (MC IV) and the hamate bone are frequently involved, either isolated or in combination. Conservative treatment appears to be sufficient only in rare cases, while surgical management is generally preferred. The choice of surgical approach and fixation technique, ranging from transfixing or reduction Kirschner wires to screw or plate osteosynthesis, depends on the specific injury pattern and should be determined on a case-by-case basis.

Despite the complexity of these injuries, clinical outcomes after appropriate surgical management are generally favorable. However, robust long-term data addressing postoperative functional limitations and the development of post-traumatic osteoarthritis remain limited. In mid-term follow-up, hand therapy can achieve good results in terms of strength and function. In cases of post-traumatic osteoarthritis with persistent symptoms, various salvage procedures are available, each associated with distinct advantages and risks.