Patellofemoral cartilage injury

Brief introduction of patellofemoral joint cartilage injury Articular cartilage damage is very common in sports injuries, but because of the difficulty in diagnosis, especially early diagnosis is almost impossible in routine examinations, it is often ignored and not treated in time, but no matter what type of cartilage damage, ultimately Both may cause degeneration and necrosis of chondrocytes and leave permanent damage, so it has attracted attention in recent years. basic knowledge The proportion of illness: the incidence rate is about 0.005%-0.008%, more common in car accidents Susceptible people: no specific people Mode of infection: non-infectious Complications: patella softening

Causes of patellofemoral articular cartilage injury

Acute or chronic trauma (25%):

It may directly hit the cartilage, destroy the collagen fiber mesh arch structure in the cartilage, and directly cause the tangential fracture of the cartilage. Chrisman has studied the relationship between trauma and tibial rickets in a biochemical perspective for many years. He found that the cartilage was damaged within 2 hours after the trauma. The concentration of free arachidonic acid in cartilage can be increased by 4 times. Arachidonic acid is the main component of phospholipid membrane. The prostaglandin precursor, its product is converted into prostaglandin E2, stimulates AMP circulation, releases tissue protein kinase, and destroys cartilage matrix. The chain of chondroitin sulfate and protein binds the cartilage matrix, causing the cartilage to soften, and the metabolites enter the synovial fluid to cause a synovial inflammatory reaction. The inflammation stimulates the synovial membrane to release a large amount of enzymes, further destroying the cartilage and causing a vicious circle.

Stenosis of the patellofemoral joint (20%):

Long-term abnormal friction and compression of the tibial cartilage, especially in the knee flexion position, repeated lifting, jumping, weight, and torsion can cause excessive stress or uneven stress distribution between the patellofemoral, making the tibia Cartilage is prone to damage and suffers from osteochondrosis.

Tibial joint instability (15%):

Common unstable factors such as high or low tibia, abnormal knee Q angle, sacral tilt, tibial torsion deformity, abnormal development of the humerus or femoral condyle, due to abnormal position of the humerus or abnormal alignment of the line, or the contact surface between the patella, The contact stress is abnormal and the tibial rickets are caused. Many scholars have done a lot of work on the stress distribution and stress test of the patellofemoral joint. There are high contact pressure theory, low contact pressure theory, pressure division unevenness theory and tibia intraosseous pressure. Increased doctrine, etc., have experimental support, but whether the pressure is too high, the pressure is insufficient or the pressure segment is uneven, as long as the pressure exceeds or does not reach the normal range of the tibial cartilage, it may lead to cartilage degeneration.

Pathological change

The main pathological changes of tibial cartilage are manifested as softening, yellowing, cracking, exfoliation, ulcer formation, synovial inflammation, increased secretion, periorbital fasciitis, inflammatory bandage and hyperplasia Contracture, the exfoliated cartilage pieces may be freed into joint rats in the joint cavity, causing the knee joint to interlock.

Any mechanism that affects the normal secretion of the synovial membrane or the articular cartilage extrusion mechanism, which hinders the normal movement of the joint, can cause damage to the articular cartilage.

The lesions of the athlete's tibia cartilage were most common in the medial plane, followed by the central zone (60° contact zone) and the medial zone. However, Ficat reported the highest incidence in the lateral zone.

Rijnds divides the cartilage lesions of the tibial chondroma into four degrees. The first degree is the fine fissure of the cartilage surface. The cartilage in the lesion area is soft, mildly swollen and yellowish, which is roughly equivalent to the first layer (stationary layer) of chondrocytes. The second layer (transition layer) and the third layer (mast cell layer) of the cartilage are damaged, and there are shallow cracks visible to the naked eye. The third degree is the damage of the fourth layer (calcification layer) of the cartilage, and the fissure is deepened, and the subchondral bone can be locally reached. The cartilage fragments are exfoliated from the surface layer. The IV degree is the damage to the subchondral bone, the ulcer is formed, the local cartilage is completely destroyed, and the healthy cartilage is often eroded around the lesion. The adjacent cartilage often has different degrees of degeneration.

Prevention of patellofemoral joint cartilage injury

Any mechanism that affects the normal secretion of the synovial membrane or the articular cartilage extrusion mechanism, which hinders the normal movement of the joint, can cause damage to the articular cartilage.

Complications of iliac joint cartilage injury Complications, patella softening

Can be combined with free joints and joint effusion, tibial rickets.

Symptoms of patellofemoral articular cartilage injury Common symptoms Single leg half astringent pain After pain, joint effusion, bone softening, sputum, tenderness, tenderness, sputum, sputum, sputum, sputum

1. The most common symptom of general symptoms is post-temporal pain. It occurs in active or semi-sacral position. It is acid-absent and discomfort at the beginning. It develops into persistent or progressive soreness. It often causes pain when starting activities, and it is relieved after activity. The pain is aggravated at the end or at rest. This pain is sometimes very distinctive. It is often described as caries and soreness. It is sore on the stairs, especially when going downstairs or downhill. It often has knees that are soft, a little fall. The chief complaint is that there are sometimes joint interlocking symptoms.

2. In terms of physical signs, the main features are as follows:

(1) tibia grinding tenderness: mostly positive, the incidence rate is almost 100%.

(2) Pushing and resisting pain: It is also positive, pushing the tibia to the distal end, and the quadriceps contraction, and the soreness is positive under the armpit.

(3) Single-legged semi-squat test: mostly positive, this sign is one of the most significant and diagnostic value of tibial chondrosis. The positive rate of this sign is 100%, and Chen Shiyi reports more than 93%.

(4) quadriceps atrophy: more obvious, especially the medial head is more significant.

(5) Knee joint effusion sign: more positive in the middle and late stage, the floating sputum test can help diagnosis, when the amount of knee joint effusion less than 30ml, can be found by effusion induced bulging test, joint puncture can extract light yellow transparent Liquid, even turbid joint fluid can be extracted.

(6) Periorbital tenderness: When the tibial chondrosis is accompanied by inflammation of the surrounding soft tissue, pain can be caused by scraping the periorbital with the index fingernail.

(7) When it occurs, it repeats many times and is caused by the friction of rough and uneven cartilage. There are not many opportunities for sputum pronunciation, but many authors believe that the rough sputum pronunciation at a fixed angle after sputum is meaningful for diagnosis.

Examination of patellofemoral articular cartilage injury

1. X-ray filming of ordinary X-ray film does not make much sense for diagnosis, but you can choose the axial slice of the humerus at different knee angles to observe the shape of the humerus, the degree of hardening of the subchondral bone of the humerus, and measure some indexes of the tibia. For example, the humerus angle, the tibia depth index, the tibia index, the groove angle, the overlap angle, etc., the lateral X-ray film of the knee joint can detect the abnormal position of the humerus. In normal time, the length of the tibia (P) is equal to the length of the patellofemoral ligament (PT). When the PT exceeds 15% of P or exceeds 1 cm, it is a high tibia.

2. MRI examination can be found in the exfoliation and ulceration area of the tibial cartilage.

Diagnosis and diagnosis of patellofemoral articular cartilage injury

Diagnostic criteria

1. Clinical characteristics When the patient is active, complaining of soreness after sputum, symptoms such as aggravation of pain when going up and down the floor or half a squat, combined with signs such as tenderness of the tibia, sputum sputum, single leg and half sputum pain, periorbital tenderness, etc. Diagnosis of the disease.

2. Imaging examination

(1) X-ray findings: taking ordinary X-ray film does not make much sense for diagnosis, but you can choose to take the axial slice of the humerus at different knee angles, you can observe the shape of the tibia, the degree of hardening of the subchondral bone of the humerus, and measure the humerus. Some indexes, such as humerus angle, tibia depth index, tibia index, groove angle, overlap angle, etc., lateral X-ray film of the knee can detect abnormal position of the humerus. Normally, the length of the tibia (P) is equal to the length of the patellofemoral ligament (PT). When the PT exceeds 15% of P or exceeds 1 cm, it is a high tibia.

(2) MRI examination: exfoliation and ulceration of the tibial cartilage can be found.

3. The final diagnosis depends on the diagnosis of arthroscopy, surgical exploration or MR examination.

Differential diagnosis

Physical examination should pay attention to the synovial syndrome of the knee joint (Plica syndrome), femoral tibial rickets, etc., and the clinical examination is often performed after the pain point is sealed, as a diagnosis.

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