1.Pathogenesis
At the end of the finger, there is a tendon on the palmar side and a tendon on the dorsal side to perform the function of flexion and extension respectively. 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 while 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.Post-injury performance
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. Generally, pain is rarely felt, and most of the pain is due to combined fractures.
3.What tests to do
Usually only a radiograph is needed to clarify whether there is a combined fracture and whether there is a 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 you need surgery?
Since the success rate of surgery is not high and there are more problems after surgery, I believe that surgical treatment should not be the first choice. 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, semi-dislocated joints (unstable), and those who come to the clinic very late (more than 1 month) when formal conservative treatment has not worked, surgery is the treatment of choice.
Of course, there are still academic controversies, and some people recommend early surgery. There are also a variety of surgical methods. At present, the overall efficacy is similar.
5.The strategy of conservative treatment
The so-called conservative treatment is to treat the hammer finger by choosing a splint (i.e., a 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.
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. To the best of my knowledge, the fixation of the proximal interphalangeal joint does not affect the outcome of treatment.
6.How long does it need to be fixed
The most basic treatment is to start with 6 weeks of immobilization.
After that, the brace is removed to check the results. If you can straighten it, then you can stop wearing the brace during the day, but you should wear it at night for protection for 2 weeks.
If, after 6 weeks of basic treatment, the brace is still not straightened, then it is necessary to continue wearing 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.Caution
There are various kinds of splints, as long as they can maintain the hyperextension or straightening of the end joint. During the fixation period, you should observe the posture of your finger in the splint yourself to see if it stays 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 help from others is needed to maintain the posture of the finger.
8. Complications
Problems that may arise include: still unable 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.