How to treat lunate bone necrosis

Lunate bone necrosis is more common in young people around 20 or 30 years old. Since the epiphysis has closed, it is no longer classified as a chronic injury of the epiphysis, but is classified as a chronic bone injury. For patients with complete necrosis and deformation of the lunate, lunate resection or artificial prosthesis implantation can be performed for treatment. If the radiocarpal joint osteoarthritis is very serious, radiocarpal joint fusion should be considered.

1. Causes

There are different reports on the causes of lunate bone necrosis, but it is generally believed to be related to chronic injuries and fractures. Analysis showed that the injury led to occlusion of the lunate nutrient artery, resulting in lunate ischemia, which further developed into lunate ischemic necrosis. Aseptic necrosis of the lunate bone is one of the important causes of disability in the wrist. This disease is more common in people aged 20-40, with males being twice as likely as females. It is more common in people who move their wrists frequently, especially some handicraft workers and operators of pneumatic picks and oscillators.

1. symptom

   Lunate bone necrosis has a slow onset, with the main symptoms being swelling, pain and fatigue in the wrist joint, which worsens with activity and is relieved after rest. The pain worsens with increased activity, and the original job cannot be continued due to limited activity. Typical clinical manifestations are dorsal wrist pain, decreased grip strength, and limited wrist movement.

   The disease is roughly divided into four stages: Stage I is characterized by wrist pain only, especially when the wrist is extended, and no changes on X-rays; Stage II is characterized by further aggravation of wrist pain, and a lower grip strength than the healthy side. X-rays show increased density of the lunate bone, irregular changes in the trabeculae, but normal morphology of the lunate bone; Stage III is characterized by wrist swelling and pain, which may radiate to the forearm, and significantly limited wrist extension. X-rays show that the lunate bone is compressed and flattened, and the bone density is obviously uneven, but there are no bone fragments; Stage IV is a combination of Stages II and III lesions with lunate fragments, and occasionally carpal tunnel syndrome.

   Treatment

   In the early stage, the wrist joint can be fixed in the dorsiflexion position of 20 degrees to 30 degrees. The fixation period should be checked by regular X-rays or radionuclide bone imaging until the morphology and blood supply of the lunate bone are restored, which usually takes about 1 year. If the fixation device is removed prematurely, the lesion is prone to recurrence. The treatment of lunate aseptic necrosis according to Lichtman staging is a common clinical method.

   1. There are no abnormalities in X-ray examinations of patients in stage I. If necrosis is suspected at this stage, conservative treatment is required.

   2. Stage II patients should be treated with surgical methods that reduce lunate load, prevent collapse, and perform blood vessel reconstruction and biomechanical surgery.

   3. Patients in stages III and IV are in critical condition. Conventional surgical methods cannot restore the collapsed and broken lunate bone to its original state and function, which can easily lead to secondary synovitis. Therefore, the necrotic lunate bone should be removed and lunate replacement surgery should be performed, and biomechanical treatment methods can be used in combination.

   4. Patients in stage IV have developed extensive traumatic arthritis of the wrist joint, necrosis and fragmentation of the lunate bone, and loss of function of the entire wrist cartilage. At this time, proximal row carpectomy, radiocarpal fusion, lunate resection and peripheral interosseous joint fusion, and wrist nerve branch transection can be used.