Transradial Perilunate Fracture-Dislocation With Lunotriquetral Coalition.

Perilunate fracture-dislocations are devastating injuries, and their occurrence in the presence of a congenital carpal coalition is exceedingly rare. This combination fundamentally alters normal wrist biomechanics and significantly complicates surgical decision-making. We present a case of a 52-year-old female with acute hand ischemia following a high-energy motorcycle collision. Radiographic evaluation revealed a transradial perilunate fracture-dislocation complicated by a unilateral Minnaar type 3 congenital lunotriquetral coalition. Emergent closed reduction was performed, which immediately restored distal perfusion. The patient subsequently underwent minimally invasive percutaneous fixation. At the 12-month follow-up, she exhibited persistent radiocarpal pain, a severely restricted arc of motion, and radiographic evidence of carpal subluxation with early post-traumatic arthrosis. The coexistence of a transradial fracture-dislocation and a complete lunotriquetral coalition alters typical trauma kinematics, concentrating massive deforming forces across the intact intervals. While prompt closed reduction is critical for neurovascular salvage, this case highlights that selective percutaneous fixation is inadequate for maintaining long-term stability in such complex variants. Rigid internal fixation and robust capsuloligamentous repair are likely necessary to prevent rapid joint degeneration.