Abstract
We report a rare case of volar lunate subluxation that occurred after volar locking plate fixation for a volarly displaced distal radius fracture. The patient was a 63-year-old male who was injured when his motorcycle collided with a car. He had a right volarly displaced distal radius fracture (AO/OTA classification 2R3B3), an ipsilateral femoral neck, segmental shaft, and distal femur fracture that extended to the knee joint, as well as a traumatic subarachnoid hemorrhage as complicating injuries. The distal radius fracture was internally fixed with a volar locking plate (VALCP Plate). At re-examination five months postoperatively, plain radiographs and computed tomography images showed that the distal radius fragments were fused while being volarly displaced and the lunate was volarly subluxated. Although the patient only reported mild pain, radiocarpal arthrodesis, and ulnar head resection were performed nine months after the original procedure due to concerns about future rupture of the finger flexor tendon. As of 12 months after the additional operation, the patient was engaged in design work, as he was before the injury, and had 'good' wrist function, achieving 70 points in the evaluation criteria by the Japanese Society for Surgery of the Hand. The causes of postoperative volar subluxation of the lunate were thought to be insufficient fixation force on volar lunate fossa fragments, femoral fractures as complicating injuries, and axial pressure applied to the radial joint surface when the patient used his hands to walk with a walker or stand up.
