I. Overview The tendon system of the hand can be roughly divided into flexor tendon system and extensor tendon system, and the extensor tendon system can be roughly divided into extensor wrist tendon and extensor finger tendon. Injuries to the extensor tendons of the hand are very common and have a greater impact on hand function, but the treatment is more complex and varies for different tendons, different sites, and different injury mechanisms. It is recommended that patients must follow the treatment recommendations of a hand surgeon. Second, the etiology of hand extensor tendon injury is more complex, the most common cause is the direct trauma to the hand, such as: cutting injuries with sharp objects or direct blows or extrusion with blunt objects. In addition, extensor tendon injury can also be secondary to other diseases or injuries, such as: distal radius deformity healing, wrist synovitis, rheumatoid arthritis, etc. Third, the clinical manifestations of extensor tendon injury, the main manifestation is the finger of a joint or the entire finger active straightening disorder, and passive can be straightened, and not accompanied by the sensory disorder of the finger. Since there are three wrist extensor muscles, a single extensor tendon injury does not easily show the symptoms of wrist extension disorder. If it is an open injury, sometimes the severed end of the tendon can also be seen within the wound. Fourth, the examination of extensor tendon injury should be based on different sites and different etiologies for the appropriate examination. If the injury is suspected to be secondary to diseases such as distal radius fracture or wrist synovitis, the original disease should first be clarified by X-ray plain film or CT, MRI and other imaging examinations. In the case of an injury to the extensor tendon stop a lateral plain radiograph of the affected finger is required to determine whether there is an avulsion fracture. The diagnosis of extensor tendon injury itself mainly relies on clinical examination, of course, some of the extensor tendon injury can also be diagnosed clearly by ultrasound, magnetic resonance examination can also diagnose part of the extensor tendon injury, but if the injury site is more terminal, the specificity of its diagnosis is not very high. Diagnosis Usually, it should be easy to establish the diagnosis based on the clinical manifestations such as active extension disorder of the finger, combined with ultrasound and plain film examination. However, when establishing the diagnosis, it is best to also clarify whether the injury is primary or secondary, what kind of disease it is secondary to, whether the injury is acute or chronic, the location of the injury, the degree of contamination of the wound, whether it is combined with other tissue (bone, muscle, nerve, etc.) injury, and whether there is a tendon defect. Because these conditions are directly related to the treatment of closely related. Six, treatment 1, acute open extensor tendon injury treatment for acute fresh open extensor tendon injury should first be based on the degree of contamination of the wound, first debridement, the contamination and necrotic tendon tissue to be removed, if the contamination is not serious, the tendon does not exist defects, can be directly suture repair, if the contamination is heavy, after debridement there is a tendon defect, you can take the tendon for transplant repair, if the contamination If the contamination is serious or combined with extensive soft tissue injury, the risk of postoperative infection is predicted to be greater, the tendon defect can be cleared first, and the tendon defect can be left open, and then the tendon transplantation can be repaired after the infection is controlled and the soft tissue is repaired. 2, chronic extensor tendon injury treatment is generally considered for more than 2 weeks of extensor tendon injury, due to the tendon injury may exist after the tendon retraction effect, there may be a tendon defect, in the surgical treatment, based on the tension of the tendon to determine whether the need for tendon graft repair. 3, closed extensor tendon injury treatment for closed extensor tendon injury, after clear diagnosis and etiology, if there is no local infection or soft tissue defect, tendon repair should be performed as soon as possible, and treatment should be carried out at the same time for the etiology (such as: correction of distal radius deformity, treatment of rheumatoid arthritis, etc.). During the surgery, it is necessary to decide whether the tendon should be repaired directly or by tendon grafting or transposition according to the specific situation. 4, special parts of the extensor tendon injury treatment 4.1, the extensor tendon tendon ventral junction injury extensor tendon if in the tendon and muscle ventral junction part of the injury, generally in the direct repair is often poor function, mainly because of the poor gliding tendon, so, this part of the injury is often the second phase of the surgery such as tendon transposition and other functional reconstruction. 4.2, extensor tendon stop site injury extensor tendon stop site injury is often manifested as drooping finger deformity, that is, the distal interphalangeal joint of the finger active straightening disorder, such injury can be divided into combined fracture injury and non-combined fracture injury, if it is a fresh non-combined fracture injury, feasible over-extension brace fixation; if it is an old non-combined fracture injury, feasible extensor tendon tightening suture; if it is a combined fracture injury, feasible extensor tendon tightening suture. If the injury is a combined fracture, open or closed reduction and internal fixation of the fracture is feasible. 4.3, tendon cap slippage acute tendon cap slippage can be fixed using extension finger position brace. Conservative treatment is ineffective for slippage and chronic tendon cap slippage requires surgery. Seven, the prevention of extensor tendon injury prevention is mainly to strengthen labor protection, strengthen pre-service training, enhance the work of workers proficiency. For secondary extensor tendon injury, early treatment of the primary disease is the best means of prevention.