Transscaphoid Transcapitate Perilunate Fracture-dislocation with Inferior Arc Injury and Acute Ulnar Nerve Compression: A Case Report

INTRODUCTION: Perilunate dislocations and perilunate fracture-dislocations (PLFD) are relatively uncommon injuries, comprising <10% of wrist injuries. Perilunate injuries are often complicated by median neuropathy reported in 23–45% of cases, whereas there are very few reported cases of associated ulnar neuropathy. Combined greater arc and inferior arc injuries are also rare. We report an unusual PLFD pattern with associated inferior arc injury and acute ulnar nerve compression. CASE REPORT: A 34-year-old male sustained a wrist injury after a motorcycle collision. Computed tomography scan revealed a trans-scaphoid, transcapitate, perilunate fracture-dislocation, and a distal radius lunate facet volar rim fracture with radiocarpal subluxation. Examination revealed acute ulnar neuropathy without median neuropathy. He underwent urgent nerve decompression and closed reduction, followed by open reduction internal fixation the next day. He recovered without complication. CONCLUSION: This case emphasizes the importance of a thorough neurovascular examination to rule out less commonly seen neuropathies. With up to 25% of perilunate injuries misdiagnosed, surgeons should have a low threshold for advanced imaging in high-energy injuries.