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KembaraXtra -Medicine- Emergency and Acute Medicine – Perilunate Dislocation
Perilunate dislocation is a serious high-energy wrist injury in which the lunate remains aligned with the distal radius, while the distal carpal bones—most notably the capitate—are displaced dorsally in approximately 95% of cases and volarly in about 5%. It is an unstable injury that requires early surgical treatment because it carries a high risk of long-term complications, particularly post-traumatic arthritis. The scaphoid is frequently fractured in association with perilunate dislocations.
The usual mechanism of injury is wrist hyperextension combined with ulnar deviation. These injuries typically result from significant trauma such as falls from height, motor vehicle accidents, industrial accidents, or sporting injuries. Because of the force involved, concomitant upper extremity injuries are common and must always be assessed.
Patients typically present with severe wrist pain, marked swelling, and diffuse tenderness. There may be decreased range of motion and sometimes visible deformity. Paresthesias in the median nerve distribution are common due to swelling and compression within the carpal tunnel. A careful history often reveals a high-energy injury. On examination, the wrist is swollen and painful with limited motion. Sensory changes in the median nerve distribution may be present, and neurovascular status—including capillary refill and 2-point discrimination—must be carefully assessed and documented. Skin integrity should be evaluated, as open injuries can occur. Importantly, this diagnosis is frequently missed on initial evaluation.
Radiographs of the wrist are essential and must include AP, lateral, and oblique views. The true lateral view is most diagnostic. Normally, the radius, lunate, and capitate should align in a straight line on the lateral film. In perilunate dislocation, the lunate remains aligned with the radius, but the capitate is displaced dorsally (most commonly) or volarly. CT or MRI is generally not required in the emergency department but may be used for preoperative planning.
The differential diagnosis includes lunate dislocation, lunate fracture, scapholunate dissociation, distal radius fracture, and other ligamentous wrist injuries. In pediatric patients, nonaccidental trauma should be considered.
Management begins with assessment for more serious associated injuries, followed by immobilization, elevation, ice application, and adequate pain control. Closed reduction should be attempted emergently. Traction is applied for approximately 10 minutes using finger traps with counterweights, followed by manual traction. The injury is briefly recreated with wrist extension while volar pressure is applied over the lunate, and then slow wrist flexion is performed to relocate the distal carpal bones. After reduction, the wrist should be immobilized in a sugar-tong splint in neutral position, post-reduction radiographs obtained, and neurovascular status reassessed. Procedural sedation is often required.
Definitive treatment requires operative fixation with ligament repair to restore stability and minimize long-term complications. All patients should have urgent hand surgery consultation.
Patients should be admitted if the injury is open, irreducible, associated with neurovascular compromise, or part of multiple trauma. Closed injuries with successful reduction and intact neurovascular status may be discharged with reliable orthopedic follow-up within 2–3 days, though all cases ultimately require surgical evaluation.
Complications are common even with appropriate treatment and include median nerve injury, tendon problems, wrist instability, complex regional pain syndrome, decreased grip strength, and post-traumatic arthritis. Up to 25% of these injuries are missed at initial presentation. Delayed diagnosis significantly worsens outcomes and may necessitate salvage procedures.
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