1, pathogenesis of the end of the finger, in the metacarpal and dorsal side of each tendon, respectively, to complete the function of flexion and extension of the finger. The dorsal tendon responsible for finger extension is very thin and easily ruptured after trauma. In some accidents, the tendon can be torn when the finger is subjected to a sudden bending stress in the extended position. For example, poking while playing basketball is the most common, others are poked when falling, or while putting on clothes, or even when the finger is injured while bouncing the head. Along with the tendon tear, some patients will have a small avulsion fracture at the same time. In rare cases, a relatively large fracture and joint dislocation will occur. 2. After the injury, the last section of the finger cannot be straightened actively, but can be straightened passively, and the finger is bent down like the head of a hammer. Bending is not affected. The dorsal side of the last joint can be somewhat swollen. Pain is rarely felt, and most of the pain is due to a combined fracture. 3.What tests to be done usually only need to take a film to clarify whether there is a combined fracture and whether there is joint dislocation. The most important thing to note is that the radiographs must be taken in standard ortho- and lateral positions, otherwise small lesions may not be detected. 4.Do I need surgery? Surgical treatment should not be the first choice because of the low success rate of surgery and the high number of post-surgical problems. For most patients, conservative treatment is preferred. Even if it is found late, usually within one month, a better result can be obtained by conservative treatment. Only for those patients with large fracture masses, subluxation (instability), and those who come to the clinic very late (more than 1 month) when formal conservative treatment is not effective, surgery is the treatment of choice. Of course, there is still academic controversy, and some people recommend early surgery. There are also various surgical methods. At present, the overall efficacy is similar. 5, conservative treatment strategy: the so-called conservative treatment is to choose a splint (i.e. brace) to fix the finger in a suitable position and maintain it for a certain period of time, so that the avulsed tendon or fracture fragment and the base of the finger bone can maintain contact and achieve a certain strength of healing to treat the hammer finger. The most important thing is to keep the distal interphalangeal joint straight, and personally, I think it is best to hyperextend it a bit. In the past, flexion of the proximal interphalangeal joint was considered preferable, but because prolonged flexion may lead to joint contracture, most people now prefer not to fix the proximal interphalangeal joint, and some people fix it in the extended position. Within my personal knowledge, the fixation or not of the proximal interphalangeal joint does not affect the therapeutic effect. 6.How long does it need to be fixed: The most basic treatment is to maintain the fixation for 6 weeks at the beginning. After that, the brace is removed to check the effect. If you can straighten it, then you can stop wearing the brace during the day, but you should wear it at night to protect it for 2 weeks. If, after 6 weeks of basic treatment, the brace is still not straightened, it is necessary to continue to wear it for 2 weeks and then check the results. If it is not good, you can continue for 2 more weeks. And after that it is still 2 weeks of nighttime protection. With this conservative treatment, most of them can regain straightness. If the treatment is really bad, you can choose surgery. 7. There are various kinds of splints, as long as they can maintain the hyperextension or straightening of the end joint. Observe the posture of the finger in the splint during the fixation period to see if it is maintained as before. If there is any looseness, it needs to be adjusted evenly. If the finger is very purple, it needs to be relaxed properly. The skin on the dorsal side of the joint may sometimes have pressure sores and superficial necrosis, and excessive pressure needs to be avoided. When needed, local cleaning can be performed, but the help of others is needed to maintain the posture of the finger. 7. Complications have possible problems including: still not being able to straighten, or straightening is corrected and bending is affected instead. There is a small protrusion behind the end joint. Skin pressure sores. Flexion contracture of the proximal interphalangeal joint. Also associated with surgery include: infection, wound dehiscence, suture reactions, internal fixation (wire, plate, anchor nail) coming out, or remaining in the body.