(Disclaimer: This article is for scientific purposes only. In order to protect the patient’s privacy, the relevant information in the following content has been processed) Abstract: The patella is prone to acute dislocation in the event of sprain, and there will be obvious swelling in the knee joint, and the dislocated patella can be easily reset on its own in the event of knee straightening, and the dislocated patella was reset outwardly at the time of the patient’s hospital examination, and there were obvious clinical manifestations of swelling, pain, and subcutaneous ecchymosis in the joint. After physical examination and radiography, it was confirmed that the patella was dislocated, and the patient was hospitalized and underwent repair of the medial patellar support ligament to restore the patella’s trajectory and knee joint function. Basic information] Female, 33 years old [Disease type] Patellar dislocation [Hospital] Harbin No.1 Hospital [Date of consultation] February 2021 [Treatment plan] Surgery (surgical repair of the medial patellar support ligament) + rehabilitation (knee flexion and extension + quadriceps strength training) [Treatment cycle] Hospitalization for 7 days, outpatient follow up for 1 month [Effect of treatment] Patellar reset and fixation, pain relief, and knee joint activity resumed. Pain relieved, knee joint resumed activities I. Initial Consultation Patient Ms. Zhang described herself: When the knee is sprained, the knee joint is in flexion, the femur rotates externally and the fixed tibia rotates internally forcefully causing the patella to be dislocated, and at the same time the quadriceps muscle is tense, pulling the patella outward, which can also cause patella dislocation at the same time. After patellar dislocation, the medial supporting ligament can rupture and the patella slips out of the lateral condyle of the femur, which can easily cause chondral fracture of the patella. According to the patient’s condition at the onset of the disease, it was confirmed that the patella was dislocated during the sprain, and the patient forced to straighten the knee to reset the patella, there was severe swelling and pain in the knee joint, and the patient did not dare to walk with weight-bearing, and it was confirmed that the patella was obviously tilted to the lateral side by the three-dimensional CT scanning examination. After communicating with the patient, we chose surgery to repair the medial patellar support ligament. In the process of surgical treatment, it was confirmed that the patient’s medial patellar support ligament was ruptured, with local bleeding and the formation of a small hematoma. After cleaning, the medial support ligament was re-sutured to restore the stability of the medial side of the patella. During the suturing process, it was confirmed that there was no obvious increase in patellofemoral joint pressure, and there was no obvious limitation in proper flexion and extension of the knee joint, and the surgical incision was closed. After surgery, the knee was immobilized with a long leg brace for 4-6 weeks, and under the guidance of the rehabilitation doctor, knee flexion and extension activities were started to restore the range of motion of the knee joint. At the same time, strengthen the quadriceps muscle strength training, not only to restore the muscle strength of the lower limb, but also to improve the stability of the patella, especially the medial head of the quadriceps muscle strength training is particularly important. Surgery can directly repair the medial patellar supporting ligament, maintain the stability of the patella, restore the running track of the patella in the femoral scooter, ensure the function of the patellofemoral joint, and restore the range of motion of the knee joint. After surgical treatment and rehabilitation, the patient’s knee joint was restored to the normal functional level, and the pain symptoms were significantly improved in a short period of time. The patient was discharged from the hospital after 7 days of hospitalization, and was followed up in the outpatient clinic in 1 month, and due to the fact that he started rehabilitation at an early period of time, he did not have any adverse consequences such as serious knee stiffness and adhesion, and did not have any lower extremity deep vein thrombosis. Fourth, precautions We are glad that the patient’s symptoms have been relieved after treatment. Although the patient is completely cured after treatment, he still needs to pay attention to the protection of the patella, and if patellofemoral pain occurs again, he needs to go to orthopaedic clinic for follow-up in time to confirm whether there is any damage to the patellofemoral articular cartilage. At the same time should be through the knee flexion and extension activities exercise, rapid recovery of knee flexibility and range of motion, to ensure that the knee joint function back to normal, the exercise process should follow the principle of gradual and orderly, do not violent activities, daily life, strengthen the lower limb muscle exercise. Diet, it is recommended that long-term adherence to drinking milk, regular supplementation of beef and other high-protein substances, can promote muscle growth, thereby protecting the patella. Since the surgery will change the patellofemoral joint pressure, the patient needs a period of time to gradually adapt to the knee flexion and extension activities, and the knee activities should be fully restored to the normal level in 3-6 months under normal circumstances. V. Personal perception The reason why the patient occurred patellar dislocation, mainly due to the knee joint sprain, at the same time, the patient’s femur trolley there is a certain degree of shallow flat phenomenon, resulting in the patella running process of decreased stability, therefore, the usual life should be to prevent knee sprain, strengthen the leg muscle exercise, to avoid strenuous exercise of the lower limb joints. Frequent going up and down stairs and squatting is harmful to the patient’s patella, can cause wear and tear of the patellar cartilage, thus making the patellofemoral joint to face the degree of cohesion deterioration, can accelerate the degeneration of the patellofemoral joint, the formation of patellofemoral dislocation of the pathological basis of the patellofemoral dislocation, need to pay attention to the correction.