Ischemic necrosis of the lunate, also known as Kienbock’s disease. The etiology of the disease is unclear, but ischemic changes in the lunate bone are generally thought to be related to the circulatory system, traumatic factors, and other factors. In young patients with pain and stiffness in the dominant hand, osteonecrosis of the lunate should be highly suspected. Pressure pain can be palpated on the dorsal side of the lunate, and the grip strength of the affected hand is significantly reduced. Patients often complain of vague dull pain at the radial lunate joint, and some patients have a history of dorsal extension injuries, with pain aggravated by activity and alleviated by rest. On X-ray, increased bone density of the lunate is an early manifestation of necrosis, and MRI diagnosis is more sensitive. Typical imaging manifestations: sclerosis of the lunate, progressive loss of lunate density, fragmentation of the lunate in the anterior-posterior direction, progressive loss of carpal height with proximal displacement, and ultimately degenerative changes associated with rotation of the navicular bone and collapse of the carpal bones. According to the evolution of necrosis, Lichtmann classified the ischemic necrosis of the lunate into four stages Stage I: symptoms and signs such as pain, weakness, limitation of motion, dorsal tenderness and swelling of the carpal joint, and normal x-ray performance. Stage II: x-ray shows increased density of the lunate with fragmentation, but there is no obvious change in volume, shape and anatomical relationship with adjacent bones. In later stages, the height of the radial half of the lunate bone decreases. There is also an increase in the dorsal swelling of the joint. Stage III: On the basis of stage II, the lunate bone collapses, with an increase in the anterior and posterior diameter of the lunate bone seen on lateral plain radiographs, and displacement of the skull to the proximal side. Stage IIIa: the correspondence between the navicular bone and the surrounding carpal bones is normal; Stage IIIb: the interarticular space between the navicular and lunate bones becomes wider, the palmar curvature of the navicular bone increases, and the ulnar side of the triquetrum is shifted. The carpal joint is stiffer than in stage II. Stage IV: In addition to collapse and fragmentation of the lunate and proximal displacement of the capitellum, the joints around the lunate show signs of osteoarthritis – rough and uneven articular surfaces, narrowing of the articular space, formation of bone redundancy, sclerosis of the bones and cystic degeneration. Once collapse of the lunate occurs, if left untreated, it progresses until the normal structure of the wrist joint is completely destroyed. Treatment Conservative treatment (applicable to the first stage): The wrist joint is immobilized by braking and fixed with physiotherapy, traditional Chinese medicine fumigation, internal medication, etc., and the braking and fixation of the wrist should be long enough. Surgery: the main treatment methods are: ulnar bone lengthening or radial bone shortening (applicable to patients with negative ulnar bone variance, but may cause ulnar bone impingement sign); lunar bone blood flow reconstruction: dorsal carpal bone arterial and venous bundles implantation, radial bone flap implantation with anterior rotator anterior muscle tip (i.e., the distal part of anterior rotator anterior muscle and myofascial as the tip, carrying part of the radial cortical implanted into the lunar bone), the base of the metacarpal bone flap with the tip of the implantation method, (i.e., with the dorsal carpal bone flap implantation). (i.e. take the dorsal carpal artery – 2nd or 3rd dorsal metacarpal artery as the tip, carry the 2nd or 3rd metacarpal base bone piece embedded in the lunate to rebuild the blood circulation); pea bone displacement repair with tip for the treatment of lunate necrosis; tendon tendon ball stuffing (i.e. remove the necrotic lunate and then the palmar tendon is sewed into a ball shape and put in the lunate bone gap); artificial lunate bone implantation; restricted Intercarpal fusion; Cephalic bone displacement substitution (i.e., remove the necrotic lunate and replace the lunate with vascular bundles proximally to reconstruct the radial-lunate joint); Proximal carpal bone removal; Carpal fusion. Ulnar lengthening or radial shortening, reconstruction of the blood flow of the lunate, is suitable for the first and second stage of lunate necrosis; pea bone displacement, tendon ball filling, artificial lunate replacement, limited wrist fusion, cephalic bone displacement substitution, and proximal row of carpal bone removal, etc., are suitable for the third stage of lunate necrosis; wrist fusion is suitable for the fourth stage of lunate necrosis. Stage IV aseptic necrosis of the lunate is often accompanied by synovitis of the carpal joint, radial lunate arthritis, carpal joint alignment disorders, and instability of the carpal joint, which ultimately leads to a significant decrease in the grip strength of the affected hand, severe pain in the carpal joint during activities, and in severe cases, can lead to complete loss of carpal joint function. The choice of treatment is based on surgery. Resection of the proximal row of carpal bones can relieve wrist pain and improve wrist function to a certain extent, but the grip strength of the affected hand is significantly reduced, and may be accompanied by instability of the wrist joint. Radiocarpal joint fusion can eliminate wrist pain and maintain the grip strength of the hand, but the palmar flexion and dorsal extension functions of the wrist are completely lost. There are many clinical reports of lunate replacement, and the substitutes after removal of the collapsed and fragmented lunate include artificial prosthesis made of metal ball, silicone rubber and titanium alloy, metacarpal longissimus tendon ball, pea bone, and cephalad bone displacement substitution. After the removal of the lunate bone, the artificial prosthesis is often filled, and the prosthesis is often fractured and dislocated in the late stage, and its long-term efficacy is poor; the implantation of the tendon ball of the palmaris longus muscle is also poor due to the implantation of the tendon ball scar and the implantation of the tendon ball, and the implantation of the tendon ball can not prevent the carpal bone from further collapsing, so its long-term efficacy is also poor; the volume of the pea bone is obviously smaller than the lunate bone, and its articulating surface does not fit the articulating surface of the peripheral articulating surface of the lunate, which may lead to the disorder of the carpal bone arrangement, resulting in carpal pain, and the dysfunction of the wrist. Domestic scholars found that the geometry, outer diameter, articular surface arc length and arc height of the cephalic bone are extremely similar to those of the lunate bone, and the displacement of the cephalic bone instead of the lunate bone can rebuild the radial carpal joint and keep the carpal height index; the dorsal branch of the interosseous metacarpal artery and the accompanying veins are enough to ensure that there is sufficient arterial blood supply and reliable venous return to the displaced cephalic bone, which effectively prevents the cephalic bone from recurring ischemic necrosis after surgery. After a large number of clinical research and practice, it is believed that cephalic displacement to replace the collapsed necrotic lunate bone is a more certain therapeutic efficacy and faster recovery method for the treatment of aseptic necrosis of the lunate bone in the third and fourth stages.