Perilunate

Perilunate refers to a type of wrist fracture-dislocation that involves disruption of the lunate bone's articulation with the scaphoid and the radius, and often its dorsal displacement. This injury is typically caused by a fall on an outstretched hand, leading to hyperextension and ulnar deviation of the wrist. The perilunate instability is a spectrum of injuries, with perilunate dislocations representing the most severe end.

The mechanism of injury often involves a sudden, forceful hyperextension of the wrist. This can occur in activities such as sports or industrial accidents. The primary ligamentous structures disrupted are the scapholunate ligament and the lunotriquetral ligament, which are crucial for maintaining the stability of the carpal bones.

Symptoms of a perilunate injury include severe wrist pain, swelling, and a visible deformity of the wrist. Patients often report an inability to move their wrist. Neurovascular compromise, such as median nerve compression, can also occur due to the displacement of the carpal bones and surrounding soft tissues.

Diagnosis is typically made through physical examination and radiographic imaging, including X-rays. In some cases, advanced imaging such as CT scans or MRI may be necessary to fully assess the extent of ligamentous damage and bony displacement. Treatment is surgical and aims to reduce the carpal bones back into their normal alignment and repair the damaged ligaments to restore wrist stability. Early diagnosis and prompt surgical intervention are important to minimize long-term complications like chronic pain, stiffness, and post-traumatic arthritis.