| disease | Traumatic Synovitis of the Knee and Joint Hematoma |
The knee joint has the largest synovial membrane area among all joints in the body, and its synovial membrane reaction is also the most pronounced. Active treatment should be pursued to prevent knee joint dysfunction.
bubble_chart Pathological Changes
After the synovial membrane is injured, the main reactions manifest in two aspects.
1. The blood vessels in the synovial membrane dilate, and plasma, blood cells, red blood cells, and giant cells, among others, exude into the joint fluid, leading to fibrin deposition.
2. The synovial membrane cells become active, proliferate, and produce a large amount of mucus. This synovial fluid contains white blood cells, red blood cells, a significant amount of bilirubin released after rupture, fat, mucin, and fibrin, among other components. At the same time, it causes the synovial membrane to thicken, proliferate, adhere, and the cartilage to atrophy, affecting joint function.
bubble_chart Clinical Manifestations
After a knee joint injury, symptoms such as joint swelling, pain, floating patella, and limited movement may occur. It should be differentiated from hemarthrosis. The main distinguishing features are: hemarthrosis appears immediately after the injury, while synovitis develops gradually over several hours. Hemarthrosis causes significant pain, whereas synovitis is milder. Hemarthrosis is often accompanied by systemic reactions, such as elevated body temperature, while synovitis usually lacks such responses. If necessary, joint aspiration can be performed to confirm the diagnosis.
Synovitis is a common symptom that can be caused by various conditions, such as meniscus injury, intra-articular loose bodies, chondromalacia, subcutaneous nodular hemophilia, rheumatoid arthritis, etc. Therefore, these factors should be carefully excluded during diagnosis.
bubble_chart Treatment Measures1. Correctly handle the relationship between rest and activity. Before the effusion subsides, both active and passive movements should be suspended. Severe cases require appropriate immobilization. Premature activity may lead to chronic synovitis. During the rest and immobilization phase, active quadriceps training (isometric contraction) should begin immediately. Once the effusion subsides, knee joint movement and walking can commence. Emphasizing quadriceps training is crucial in treatment.
2. Excessive joint effusion increases intra-articular pressure, stimulating nerve endings and exacerbating pain, leading to reflexive muscle spasms. In advanced stages, intra-articular adhesions may form, causing functional impairment, so aspiration is necessary. Minor effusions may not require aspiration.
3. Local physiotherapy, hot compresses, or消肿化瘀 (swelling-reducing and blood-stasis-resolving) Chinese herbal medicine can be applied.
Knee joint trauma often leads to intra-articular hematoma, usually caused by intra-articular fractures, ligament or synovial membrane injuries, surgery, etc. Other causes include scurvy, hemophilia, and pigmented villonodular synovitis, collectively referred to as spontaneous intra-articular hemorrhage.
Due to the action of fibrinolysin, hematomas in the knee joint rarely coagulate or organize, mostly remaining fluid. Red blood cells from the hematoma escape into the synovial cell spaces and remain there, as well as in the sub-synovial tissues. The rest are phagocytized by synovial cells, fragmented, and transformed into multicentric or unicentric蜗状带膜小体 (helical membrane bodies) and含铁小体 (iron-containing bodies). If the hematoma is not aspirated, hemosiderin deposition can lead to periarticular fibrosis.
Except in cases of hemophilia, any significant intra-articular hematoma, regardless of cause, should be promptly aspirated and pressure-bandaged, followed by appropriate management based on the underlying cause.
