Why does blood enter the joint?
Inside the joint there are structures with a good blood supply: synovial membrane, fat body, ligament attachment sites, subchondral bone. When injured, they rupture and blood fills the joint cavity, stretching the capsule. Hence the feeling of fullness and a sharp limitation of movements. Unlike ordinary inflammatory effusion, which accumulates over a day or more, blood appears immediately. Therefore, the doctor finds out the timing of the development of edema in great detail: they help to suspect a specific injury even before taking pictures.
- A torn anterior cruciate ligament is the most common cause in the knee.
- Intra-articular and condylar fractures
- Patella dislocation with ligament damage
- Meniscus tear in the blood supply zone
- Damage to the synovium due to bruise
- Blood clotting disorders and anticoagulant use
Symptoms
The joint quickly increases in volume, the skin over it tightens and becomes warm, the contours are smoothed out. The pain is bursting, intensifies when trying to bend or straighten the limb. Often a person cannot fully straighten his leg and walks half-bent. With a large volume of blood, the patella “floats”: if you press on it, it sinks and floats up again. After a few days, a bruise may appear below the joint - blood spreads through the soft tissues.
- Rapid swelling of the joint in the first hours
- Feeling of fullness and warmth
- Sharp limitation of flexion and extension
- Pain when supporting the leg
- Patellar balloting symptom
- Bruising appears after 1–3 days
Diagnostics
The examination begins with an x-ray of the joint in two projections to exclude a fracture. Then the ligaments and menisci are assessed: in the acute period, examination is difficult due to pain and muscle tension, so ultrasound and especially MRI play an important role, which accurately shows ligaments, menisci, cartilage and bone marrow edema. Joint puncture simultaneously relieves pain and provides information: drops of fat in the obtained blood indicate an intra-articular fracture. In case of hemarthrosis without trauma, blood clotting must be checked.
- X-ray of the joint in two projections
- Ultrasound of the joint to assess the volume of effusion
- MRI of the joint is a key method for ligaments and menisci
- Diagnostic joint puncture
- General blood test and coagulogram
- Consultation with a hematologist for repeated hemorrhages
First aid and treatment
Before being examined by a doctor, the joint needs rest: the leg is elevated, cold is applied through the fabric for 15–20 minutes several times a day, fixed with a soft orthosis or elastic bandage without strong compression, and support is limited. You can’t warm the joint, knead it or try to “work it out” with force in the first days - this increases bleeding. When a joint is tense, the doctor performs a puncture and removes the blood, which immediately reduces the pain. Further treatment is determined by the cause: the bruise is treated conservatively, ligament rupture or intra-articular fracture may require surgery.
- Rest, elevation and cold in the first days
- Orthosis or elastic fixation without excessive compression
- Limitation of support, crutches if necessary
- Joint puncture for tense hemarthrosis
- Treatment of the underlying injury, arthroscopy if indicated
- Pain relief as prescribed by a doctor
Recovery and aftermath
Blood in the joint triggers inflammation and damages cartilage, so it is important not only to remove it, but also to restore movement and muscle strength in time. Rehabilitation begins early and is built in stages: first, full extension and function of the quadriceps muscle is restored, then the amount of flexion, then strength and coordination. Prolonged immobility leads to stiffness and rapid loss of muscle mass. Repeated hemarthrosis, especially with coagulation disorders, can lead to permanent damage to the joint, so such patients need to be monitored by a hematologist.
- Early restoration of full joint extension
- Exercises for the quadriceps femoris muscle
- Gradual increase in range of motion and load
- Control of edema at every stage
- Observation by a hematologist for repeated hemorrhages
- Return to sports only after a doctor's permission