Functional Outcome of Lucerne Cast in Patients with Metacarpal Fracture with or without Proximal Phalanx Fracture: An Observational Prospective Study.

Introduction: Metacarpal fractures are among the most common hand injuries encountered in clinical practice, predominantly affecting young, active adults. The Lucerne cast (LuCa) is a semi-rigid functional metacarpal cast that immobilizes the metacarpophalangeal joints in flexion while preserving wrist and interphalangeal joint motion. Evidence regarding its outcomes across varying fracture complexity remains limited. Materials and Methods: This prospective observational study enrolled 30 adult patients with closed 2nd-5th metacarpal fractures, with or without proximal phalanx involvement, managed with the LuCa at a tertiary care center. Functional outcomes were assessed using the Michigan Hand Outcomes Questionnaire (MHQ) at 1, 4, 8, and 12 weeks. Radiological union and immobilization duration were recorded as secondary outcomes. Results: The cohort was predominantly male (80%) with a mean age of 35.27 ± 9.95 years. Isolated metacarpal fractures constituted 83.3% of cases. Mean total MHQ scores improved significantly within both fracture groups from week 1 to week 12 (P < 0.001). No statistically significant between-group differences were observed in MHQ scores at the assessed follow-up points, immobilization duration, or timing of radiological union. Conclusion: In this prospective observational study, LuCa immobilization was associated with progressive improvement in patient-reported hand function and satisfactory radiological healing over 12 weeks in appropriately selected closed metacarpal fractures, with or without associated proximal phalanx fractures.