Tendinous injuries of the extensor tendons

　　The causes of injury in extensor tenosynovitis are often sharp cutting injuries, electric saw injuries, closed injuries caused by sudden finger extension, crush injuries, etc. They often occur with nerve and vascular injuries or bone and joint injuries, and can also occur with closed lacerations.

　　All types of injuries in extensor tenosynovitis can be accompanied by joint capsule injury, and can also be accompanied by avulsion fractures of the extensor tendon insertion and joint dislocation, especially the latter two injuries are more common. The typical signs after injury are hammer toe, inability to extend the distal phalanx, and sometimes overextension of the proximal interphalangeal joint.

　　The clinical manifestations of extensor tenosynovitis are mainly that the corresponding joints lose their functional movement after the tendons are ruptured.

　　1. If the superficial flexor tendon is ruptured, the proximal interphalangeal joint of the corresponding finger cannot be flexed;

　　2. If the deep flexor tendon is ruptured, the distal interphalangeal joint cannot be flexed;

　　3. If both the deep and superficial flexor tendons are ruptured, both the proximal and distal interphalangeal joints cannot be flexed. Since the intrinsic muscles are still intact, the flexion of the metacarpophalangeal joints is not affected;

　　4. If the extensor tendons at different parts are ruptured, the corresponding joints cannot be extended, and deformities may occur.

　　Extensor tenosynovitis is mainly caused by traumatic factors, so attention should be paid to production safety, good occupational protection, and preventing wrist injuries, which are the key to the prevention and treatment of the disease. It seriously affects the patient's daily life, so active prevention should be practiced.

　　Extensor tenosynovitis is mostly caused by sharp cutting injuries, electric saw injuries, and other causes. For traumatic factors causing the disease, it is easy to diagnose and no other auxiliary examination is required. For closed injuries, a physical examination is needed, and the diagnosis can be made based on the characteristic clinical manifestations. Other examinations are not required. However, it is especially important to note that for patients diagnosed with type I extensor tenosynovitis, whether fresh or old injuries, an X-ray examination of the affected finger is required before treatment to understand whether there is a distal phalangeal joint injury.

　　Patients with extensor tenosynovitis can drink more bone soup and eat nutritious foods, such as fresh vegetables like green vegetables, cabbage, radish, carrots, tomatoes, etc., and avoid spicy and刺激性 foods. In addition, they should eat less mutton and duck meat, etc., which are considered to generate heat.

　　Eat less greasy, fried food. Avoid smoking, alcohol, and spicy刺激性 food. Tea should be drunk less, as it contains a high amount of tannins, which can affect the absorption of calcium, iron, and protein.

　　The causes of injury to the extensor tendon of the finger are mostly sharp cutting injuries, electric saw injuries, closed injuries causing sudden finger, crush injuries, etc. The degree of injury varies, and the treatment methods are also different. The specific introduction is as follows:

　　1. Extensor tendon insertion rupture:Mostly caused by stab wounds, the distal interphalangeal joint suddenly flexes and tears the attachment point of the extensor tendons, local incised wounds can also cut through. It is manifested as a hammer toe deformity, and some patients may have avulsion fractures.

　　(1) After debridement, suture the tendons, place the fingers in hyperextension of the distal interphalangeal joint and flexion of the proximal interphalangeal joint, so that the extensor tendons relax, and fix with plaster or aluminum plate for 4 to 6 weeks.

　　(2) Fix the above position for 4 to 6 weeks after closed injury. If there is a large piece of avulsion fracture, early surgery can be performed, using the 'pull-out wire method' to fix the fracture piece, and external fixation with plaster or aluminum plate splint.

　　(3) For old injuries, the proximal tendons retract, forming scars at the rupture site, causing tendons to relax. For those with little functional impact, no treatment is needed. If the functional impact is significant, surgical treatment is required. An S-shaped incision is made on the dorsal side of the distal interphalangeal joint, and the skin flap is flipped over to overlap suture the perimysium. The postoperative position is fixed for 4 to 6 weeks.

　　2. Central bundle rupture of extensor tendons when flexing fingers:The dorsal aspect of the proximal interphalangeal joint protrudes, which is prone to injury and often accompanied by central bundle rupture. Normally, both the central bundle and the lateral bundle are on the dorsal side of the finger long axis. After the central bundle is ruptured, the lateral bundle can still extend the finger. If the central bundle is not repaired in time, with the flexion of the finger, the lateral bundle gradually slides towards the palmar side. At this time, the lateral bundle cannot play the role of extending the finger, but instead makes the proximal interphalangeal joint屈曲, the distal interphalangeal joint overextended, forming a typical 'buttonhole' deformity.

　　3. Dorsal wrist, dorsal forearm, and extensor muscle tendon injury:All should be sutured in stage I for the extensor tendons that are ruptured, with good results. When the rupture occurs at the dorsal part of the wrist, the corresponding part of the transverse ligament of the dorsal wrist and the synovial sheath should be incised, so that the tendons are directly located under the skin.