What are Some Common Kneecap Injuries?

The knee joint is the largest flexor joint of the whole body. At the same time, its shape also determines that it is not a very stable joint. Therefore, the ligament structure of the knee joint plays a significant role in maintaining the normal function and stability of the knee joint. Although the knee joint is a flexor plantar joint, it can also be slightly abraded and rotated during knee flexion. The main functions of the knee joint are load bearing, transmitting loads, and participating in sports to provide a power couple for calf movements. The knee joint is not as flexible as the hip joint. It is mainly a flexion and extension exercise, but because it is located in the middle of the lower limbs, between the two largest lever arms of the body, it can withstand large forces and easily cause sprains and fractures. Especially in sports, injuries of the ligaments and meniscus are the most common.

Chinese name: Knee injury

Foreign name: Injury of knee joint

Causes of knee joint injuries and common diseases

Knee injury meniscus injury

Meniscus injuries are found in many sports, especially contact sports. They are also common in daily activities and work, and are often combined with other ligament injuries. When the calf is externally rotated relative to the femur, it is easy to damage the medial meniscus; when the calf is internally rotated, it is easy to damage the lateral meniscus. Meniscus injuries are also prone to knee flexion, overextension, or direct impact of the femur and tibia. The medial meniscus injury is reported to be 5 times more than the lateral meniscus injury abroad, while the medial meniscus injury is more common in China.

Knee injury medial collateral ligament injury

The medial collateral ligament is divided into shallow and deep layers with no obvious gap between them. The superficial layer starts near the adductor nodules and ends on the medial side of the upper end of the tibia; the deep layer starts from the medial epicondyle and ends on the medial side of the upper end of the tibia and the edge of the joint, forming a part of the joint capsule and connected to the medial meniscus. Medial collateral ligament injury results from violent effects from the outside, calf abduction and abduction or thigh adduction and adduction.

Knee joint injury lateral collateral ligament injury

Injury of the lateral collateral ligament is relatively rare. It mainly occurs when the varus of the knee is caused by the external force of the joint or other reasons. It is often accompanied by damage to the joint capsule, gastrocnemius muscle, biceps femoris, hamstring muscle, and even the common peroneal nerve.

Knee injury anterior cruciate ligament injury

The anterior cruciate ligament starts from the medial anterior region of the non-articular surface of the tibia and the anterior angle of the medial meniscus and ends at the posterior part of the medial surface of the lateral femoral condyle. It can be divided into posterior external bundle and anterior internal bundle. Anterior cruciate ligament injury is more common, and it is part of the joint injury. It can also be a simple injury.

Cruciate ligament injury after knee injury

The posterior cruciate ligament is attached behind the tibial articular surface, extends to the posterior side of the upper end of the tibia, travels on the medial side of the anterior cruciate ligament, and ends on the posterior side of the medial condyle of the femur. The posterior cruciate ligament is relatively tough, so injuries are relatively rare, mostly due to large external forces, often accompanied by other injuries.

Differential diagnosis of knee injury

Knee injury meniscus injury

Patients often have a history of trauma, post-injury pain, swelling of the knee joint immediately, pain location in the acute stage is mostly inaccurate, and pain in specific parts occurs later. After the injury, joint effusions appear, joints are interlocked, and the phenomenon of "soft legs" appears. There is a bounce during the movement of the knee joint, which can be accompanied by pain on the affected side. Two weeks later, the quadriceps atrophy can be seen, and the medial side is obvious; the joint space can touch the fixed and tender point. McMurry's Test is mostly positive and can be located. It is the most commonly used test method. The Apply test can cause pain on the injured side and can perform a squat weight test. Some people also perform a rocking test, that is, placing one thumb in the joint space of the injured side, and gently rocking the lower leg from side to side with the other hand. The thumb can feel that the meniscus enters and exits the gap, and it is positive with pain.

Knee angiography is also a commonly used inspection method. It has certain help in diagnosis and can be used to locate the injury. In some cases, it is still used by people, but it is gradually replaced by new inspection methods. The diagnosis rate of arthroscopy can reach 90%, and surgery can be performed at the same time, but the observation of the posterior angle of the medial meniscus has certain limitations. MRI examination has considerable diagnostic value for joint soft tissue injury.

Knee injury medial collateral ligament injury

After the injury, severe pain occurred on the medial side of the knee joint. The remission worsened, medial swelling and congestion occurred. Bend the knee at 30 ° to check the knee joint for abnormal joint space opening feeling, decrease in medial collateral ligament tension, and positive valgus stress test. Filming under valgus stress was used as a bilateral control. The medial space of the affected knee was enlarged by more than 10 °. MRI can make a clearer diagnosis.

Knee joint injury lateral collateral ligament injury

Patients often have a history of the external force of the medial knee joint. After the injury, the lateral knee joint is painful, swollen, and local tenderness is obvious. The fibular head is often fractured. Corresponding symptoms occur with damage to other adjacent structures. The knee varus stress test was positive, the tension of the lateral collateral ligament was reduced, and the tenderness point and abnormal opening sensation could be reached. Filming under varus stress, bilateral contrast, widened joint space on the affected side.

Knee injury anterior cruciate ligament injury

Anterior cruciate ligament injuries often have a history of acute knee trauma, often with a sense of tearing, knee pain, instability, and can not repeat or continue to exercise. Subsequently, the joints swelled, and blood was accumulated, and a positive floater test appeared. The acute phase is often unable to cooperate with detailed examination due to severe pain. Routine examination can be performed after anesthesia or acute phase. For anterior cruciate ligament injury, the anterior drawer test was positive, the Lachman test was positive, the axis shift test was positive, and the Jerk test was positive. Anterior drawer test of the vertical leg is also available to relax the muscles. A positive result indicates anterior cruciate ligament injury. X-ray plain film is of diagnostic significance for avulsion fractures. The anterior drawer test was performed with bilateral control radiographs at the same time, and the tibia was moved forward, indicating anterior cruciate ligament injury. MRI is more accurate for anterior cruciate ligament injury.

Cruciate ligament injury after knee injury

Symptoms of posterior cruciate ligament injury are similar to those of anterior cruciate ligament injury, with a clear history of acute trauma. The back drawer test was positive during the examination, and the X-ray film could be taken for diagnosis at the same time. The patient was placed in the supine position with both feet on the examination table, and the tibial tubercle collapse occurred at about 90 ° of knee flexion. When the patient's distal femur was held and the hip flexed and knee flexed, the proximal tibia moved backward more significantly, indicating that the posterior cruciate ligament was broken. X-ray examination can reveal posterior cruciate ligament avulsion bone. MRI is more accurate in the diagnosis of posterior cruciate ligament.

Knee injury examination

Knee ligament injury

Physical examination: The ligament laxity test includes the anteroposterior test of the cruciate ligament, the varus test of the lateral collateral ligament, and the special test of compound or rotational instability. Commonly used front and rear drawer test, eversion test, etc.

Knee injury meniscus injury

Physical examination methods: A large class of tests commonly used are stimulating meniscus impact tests (such as McMurray test, Apley test, and Steinmann test) to help clinical diagnosis. The principle is to produce pain or mechanical signs through axial load and rotational stress , Such as "clicks" or other sounds.

Another good functional test is to let the patient take a "duck step". Only when the meniscus has an unstable tear, especially when the posterior horn tear is involved, the patient will have pain or fear.

As part of the physical examination, special joint space tenderness should be evaluated. Both active and passive movements may be limited due to the meniscus fragment shift, and no single test can confirm the diagnosis. A complete history of meniscal tear combined with clinical examination can lead to a correct diagnosis. In addition, a comprehensive examination of the ligaments should be performed to determine if there is any other instability. An unstable knee joint may be the root cause of meniscal tear, and the presence of instability will also change the treatment of meniscal lesions.

Knee Injury Treatment Principles

Knee injury meniscus injury

In the acute stage of injury, you should take a break to rest. Suction can be performed when there is a lot of joint effusion. When a lock occurs, unlock it manually. Symptoms in the chronic phase that affect life, work, and exercise can be considered surgical treatment. Because of the deeper understanding of the important role of the meniscus, the total meniscus is extremely cautious. Most meniscus repairs or partial resections are now performed depending on the location of the injury. Surgical procedures tend to be performed under minimally invasive microscopy, and patients recover faster.

Knee injury medial collateral ligament injury

Fresh and incomplete injuries can be treated conservatively, with the knee flexed at about 30 ° to fix the varus for 3 to 4 weeks while performing quadriceps exercises. Complete rupture requires early surgical repair, and the medial arc or "S" incision reveals the site of injury. Body injuries are directly superimposed with mattress sutures and reinforced; with avulsion fractures, tendon fixation sutures or internal fixations are performed based on the size of the bone mass. Postoperative plaster fixation of knee flexion was 20 ° 30 °, adduction and inversion was performed for 4-6 weeks. When the old damage and joint instability are obvious, dynamic or static repair can be performed. Patients with meniscus, anterior cruciate ligament and other injuries were repaired separately.

Knee joint injury lateral collateral ligament injury

Lateral collateral ligament injury usually requires surgical repair, and different methods are used depending on the location of the injury. Femoral avulsion can be performed after the bone canal can be used for tendon fixation; body fractures can be directly Bunnell sutured and strengthened; fibula attachment can be fixed with avulsed bone fragments or tendon fixation. Combining other injuries requires simultaneous treatment.

Knee injury anterior cruciate ligament injury

Partial rupture of fresh anterior cruciate ligament can be fixed with plaster; complete rupture of anterior cruciate ligament can be treated early. It is also believed that muscle strength exercises can be used to maintain knee stability, and reconstruction can be performed when the joint is unstable later. There are many methods of anterior cruciate ligament and the variety of alternative materials used can not be listed one by one. In recent years, arthroscopic repair and reconstruction methods have been adopted, which have the advantages of less trauma, better function, and faster recovery.

Cruciate ligament injury after knee injury

Some people think that for acute simple posterior cruciate ligament injury, there are avulsion fractures, bone fragments need to be fixed or ligaments repaired; and posterior cruciate ligament body fracture can be achieved through quadriceps compensation to achieve knee stability. If it is accompanied by meniscus or other structural damage, it often needs surgery, repair, strengthening, and reconstruction. Most of the late posterior cruciate ligament injuries require reconstruction, with various methods and a variety of materials. Dynamic reconstruction of the patellar tendon with a bone mass at one end is a simple and effective method. Some people also use bone-tendon-bone patellar tendon reconstruction. Similarly, in recent years, arthroscopic minimally invasive surgery has been used for reconstruction under the microscope, with less damage and quick recovery.