Retropatellar crepitus

Introduction Repeatedly repeated for many times, the sputum pronunciation caused by rough and uneven cartilage friction, there are not many opportunities, but many authors believe that the rough sputum sound appeared at a fixed angle after sputum is meaningful for the diagnosis of patellofemoral articular cartilage injury. .

Cause

1. Acute or chronic trauma: It may directly hit the cartilage to destroy the collagen fiber network arch structure in the cartilage. It can also directly cause tangential fracture of cartilage. Chrisman has studied the relationship between trauma and tibial rickets in a biochemical perspective for many years. He found that the concentration of cartilage free arachidonic acid in the cartilage was increased by 4 times within 2 hours after traumatic impact. Arachidonic acid is a precursor of prostaglandins, a major component of the phospholipid membrane. Its product is converted into prostaglandin E2, which stimulates the AMP cycle, releases tissue protein kinase, and destroys the chain of chondroitin-protein binding in the cartilage matrix, causing the loss of cartilage matrix. The cartilage softening metabolite enters the synovial fluid to cause synovial inflammatory reaction and stimulates the synovial membrane to release a large amount of enzymes to further destroy the cartilage, causing a vicious circle.

2. Strain of the patellofemoral joint: long-term abnormal friction and compression of the tibial cartilage, especially in the knee flexion position, repeated jumps, weights, and torsions can cause excessive stress between the patellofemoral or Uneven stress distribution makes the tibial cartilage prone to damage and suffer from tibial rickets.

3. patellofemoral joint instability: common unstable factors such as high or low tibia, knee Q angle abnormality, humeral tilt, humeral torsion deformity, humerus or femoral condyle dysplasia due to abnormal position of the humerus or abnormal line alignment, or caused Many contactors have caused a lot of work on the stress distribution and stress test of the patellofemoral joints. The contact pressure theory of the patellofemoral joints has a lot of work. The high contact pressure theory, the low pressure contact theory and the humerus There is experimental support for the theory of increased intraosseous pressure, but whether the pressure is too high or the pressure is not uniform, as long as the pressure exceeds or does not reach the normal range of the tibial cartilage, it may lead to cartilage degeneration.

4. Pathological changes: The main pathological changes of tibial chondroma are manifested as softening and yellowing of the tibial cartilage, formation of fissure and exfoliation, and increased secretion of synovial inflammation. Periorbital fasciitis supports inflammatory changes and hyperplasia or contracture. . The exfoliated cartilage pieces may be detached into the joint mouse in the joint cavity, causing the knee joint to interlock.

an examination

Related inspection

Bone and joint MRI examination of bone and joint soft tissue CT examination

Laboratory examinations must be summarized and analyzed based on objective data learned from medical history and physical examination, from which several diagnostic possibilities may be proposed, and further consideration should be given to those examinations to confirm the diagnosis.

Physical examination:

(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 under the armpit is positive for soreness.

(3) One-legged and half-squat test: Mostly positive is one of the most significant and diagnostic signs of tibial rickets. Qumian domain reported that the positive rate of this sign reached 100%, Chen Shiyi reported more than 93%.

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

(5) Knee joint effusion sign: mostly positive in the middle and late stages, the floating sputum test can help diagnosis. When the amount of knee joint effusion is less than 30 ml, it can be detected by effusion induced bulging test. The joint puncture can extract a light yellow transparent liquid, and even the 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) pronunciation.

Differential diagnosis

Tibial pain: In the early stage of the tibia femoral pain syndrome, the knees may experience pain when walking, going up and down the stairs, and standing up under the armpits. In severe cases, there may be sudden knees unable to force or even stand unstable during walking.

Tibial fissure: The humerus is the largest sesamoid in the human body and an integral part of the knee joint. The humeral fissure is medically known as a crack fracture and is one of the types of humeral fractures.

Tibial strain: It is a common sports injury in the knee. Because the knee joint often over-extension and extension, the abnormal range of internal and external valgus, the cartilage surface under the tibia and the corresponding surface of the femur, long-term collision and crushing injury.

Preemptive emptiness: The clinical manifestations of acute patella dislocation may have a small number of patients with elastic flexion deformity, anterior temporal sensation, and a tibia that can be dislocated and dislocated outside the knee joint.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.