Knee joint dislocation

　　Knee joint dislocation is caused by strong direct or indirect violence to the upper end of the tibia, and its specific etiology and mechanism are described as follows.

　　1. Etiology of knee joint dislocation

　　The upper end of the tibia is subjected to strong direct or indirect violence, causing the knee to rotate and overextend, resulting in injury.

　　2. Pathogenesis of knee joint dislocation

　　Due to the presence of many special ligaments around and within the knee joint that maintain joint stability and function, and their toughness, traumatic dislocation of the knee joint is not common. However, when the upper end of the tibia is subjected to strong direct violence, such as in car accidents or intense competitive sports, severe tears of certain ligament structures can occur. When the violence exceeds the mechanical strength provided by the stable structure, the knee joint can dislocate, and it can be considered that dislocation of the knee joint is definitely accompanied by trauma to the stable structures of the knee joint. In some cases, violence may also cause fractures of the tibial condyle while causing ligament structure injuries, leading to fracture-dislocation of the knee joint.

　　Knee joint dislocation often also involves vascular and neural injuries, with an incidence of up to 50%. Vascular injuries are more common in anterior dislocation, and palpation of the dorsalis pedis artery and observation of distal blood flow can give an impression of vascular injury. At this time, further examination should be carried out, including arteriography or surgical exploration. Vascular embolism can lead to limb necrosis, and vigilance must be increased. Neural injuries account for 16% to 43%, with the sciatic nerve injury being the most common.

　　The symptoms of knee joint dislocation vary with the type, and the specific clinical manifestations are described as follows.

　　Section 1: (Full) Dislocation of the Knee Joint

　　1. According to the relative position of the tibial condyle and the distal end of the femur at the time of dislocation, it is divided into:

　　(1) Anterior dislocation of the knee joint.

　　(2) Posterior dislocation of the knee joint.

　　(3) Lateral dislocation of the knee joint.

　　(4) Medial dislocation of the knee joint.

　　(5) Rotational dislocation of the knee joint.

　　The frequency of the direction of joint displacement during knee joint dislocation generally follows the following order: anterior dislocation, posterior dislocation, lateral dislocation, rotational dislocation, and medial dislocation. The incidence of anterior dislocation of the knee joint is twice that of posterior dislocation, and the incidence of medial dislocation is 1/8 of that of anterior dislocation.

　　Section 2: Fracture and Dislocation of the Knee Joint

　　通常是在脱位形成过程中，由于股骨髁对胫骨髁的撞击，可以导致胫骨髁的骨折，并随着外力的持续而引起骨折移位。当然，附着处之肌肉收缩亦起重要作用。在临床上，对韧带附着点处之骨块撕脱也可看作是伴有骨折的关节脱位。

　　In the process of forming dislocation, due to the impact of the femoral condyle on the tibial condyle, it can lead to the fracture of the tibial condyle, and the fracture displacement can be caused by the continuous external force. Of course, the contraction of the muscles at the attachment points also plays an important role. In clinical practice, the avulsion of bone blocks at the ligament attachment points can also be considered as joint dislocation accompanied by fracture.

　　Third, partial dislocation of the knee

　　1. Knee dislocation usually occurs when the corresponding ligament structure of the knee is ruptured, causing the tibia to shift forward, backward, or rotate.

　　The main measures to prevent knee dislocation are to strengthen labor protection, prevent trauma, and the specific preventive measures are as follows.

　　1. The main prevention of joint dislocation is to strengthen labor protection, prevent trauma, and do sufficient preparation movements before physical exercise to prevent injury. Children should avoid forceful pulling.

　　2. Conduct a thorough warm-up before exercise to enhance the excitability, responsiveness, and resistance of muscle tissues, gradually increasing the degree of confrontation, which is helpful in reducing joint dislocation.

　　3. The self-protection measures of professional athletes when falling, such as the rolling method, are also worth learning for the general public. For example, volleyball players when diving to save the ball or football players when falling after a collision, will roll over, changing from directly extending their hands to the ground to supporting with their palms, and then rolling over sequentially from the elbows to the shoulders. Sometimes, athletes roll on the ground for several turns, as if they are severely injured, but they can stand up immediately and continue the confrontation. The reason is that the huge impact force upon landing is distributed over multiple parts of the body during the roll, thus avoiding severe injury concentrated in one location.

　　The diagnosis of knee dislocation is not difficult. Generally, it can be diagnosed based on the patient's medical history, clinical manifestations, and simple physical examination. However, the application of auxiliary examinations in clinical practice can help understand the condition of dislocation more clearly, including whether there is injury to the surrounding bones.

　　Imaging examination of knee dislocation: Standard anteroposterior and lateral X-ray films are helpful for diagnosis and differential diagnosis; if further clarification of ligament injury is needed, MRI examination and CT scan can help determine the fracture situation.

　　The diet for patients with knee dislocation should include more high-fiber foods and fresh vegetables and fruits. Specific dietary precautions are as follows.

　　1. Consume more high-fiber foods and fresh vegetables and fruits to maintain a balanced diet, including proteins, sugars, fats, vitamins, trace elements, and dietary fibers, which are essential nutrients. A combination of meat and vegetables, with a variety of food types, fully utilizes the complementary effects of nutrients among foods.

　　2. Avoid spicy foods such as chili and mustard.

　　3. Abstain from habits such as smoking and drinking.

　　After knee joint dislocation, closed reduction by manipulation is often used to achieve satisfactory reduction. For joint hematomas, they should be aspirated with sterile techniques, and then the thigh cast is fixed at the knee joint flexion of 15 degrees.^. ～20This is a temporary but good treatment measure, as it can prevent the knee from suffering further injury. The thigh cast is temporarily fixed for 5 to 7 days, during which time, a careful and suitable operation plan for repairing the ligaments can be selected. If the knee is unstable after manipulation reduction, especially if the knee is dislocated posteriorly and laterally, and if the knee shows instability after reduction, it is often possible that other tissues are embedded in the middle of the joint. If a difficult-to-reduce knee joint dislocation is encountered, an operation approach through the medial side is often performed for incision and reduction. The choice of surgical approach depends on the type of displacement direction of the knee joint dislocation. During the surgical process, it is often unclear whether to repair the damaged tissue or to excise it, which is sometimes extremely difficult. Some cases, although repaired by surgery, still show some similar symptoms of ligament injury later on. For the repair of ligament injuries, it is best to repair them early. Patients should try to have surgery as soon as possible to repair, especially like the quadriceps femoris vastus, or other large composite injuries, the surgical results are much better than non-surgical methods. Non-surgical methods are to first apply a thigh cast for observation for 5 to 7 days, and if no special circumstances occur, maintain for 6 weeks. In summary, if surgery is chosen to treat knee joint dislocation, the surgery must repair the various torn tissues caused by the knee joint's medial, lateral, or anterior or posterior structures after dislocation.

　　For cases of old knee joint dislocation and severe traumatic arthritis, joint compression fixation and fusion should be adopted. For patients with common peroneal nerve injury, most are due to excessive traction injury, and it is indeed difficult to repair and suture, about 50% of the cases leave permanent nerve palsy.

　　Due to severe injuries to all ligaments after dislocation, the prognosis of joint function is also severely impaired.