This is in response to mild trauma or even spontaneously, such as in joints (haemarthrosis) or muscles.

Hemarthrosis (or haemarthrosis, plural h(a)emarthroses) is a bleeding into joint spaces.

Joint damage from haemarthrosis (haemophilic arthropathy), potentially with severe pain, disfigurement, and even destruction of the joint and development of debilitating arthritis.

Up to a quarter of all severe ligament or capsular knee injuries leading to a haemarthrosis are associated with cartilage damage that can lead to progressive degenerative arthritis.

This may be a sign of bleeding inside the joint (hemarthrosis).

Hemarthrosis tends to develop over a relatively short period after injury, from several minutes to a few hours.

Since aspirin is also an anticoagulant, it would have worsened the hemarthrosis causing Alexei's joints' swelling and pain.

Bleeding can also affect the joint (hemarthrosis) or the area that cushions and lubricates the joint (traumatic bursitis).

Blood in the soft tissues and knee joint (hemarthrosis) may lead to bruising and a doughy feel of the knee joint.

This can allow otherwise inconsequential wounds to be life-threatening, but more commonly results in hemarthrosis, or bleeding into joint spaces, which can be crippling.

Just as OCD shares symptoms with common maladies, acute osteochondral fracture has a similar presentation with tenderness in the affected joint, but is usually associated with a fatty hemarthrosis.

A study by LaPrade et al. in 2007 showed the incidence of posterolateral knee injuries in patients presenting with acute knee injuries and hemarthrosis (blood in the knee joint) was 9.1%.

Bleeding into the joint (hemarthrosis) Damage to the cartilage, meniscus, or ligaments in the knee Failure of the surgery to relieve symptoms Knee stiffness Use of arthroscopy has reduced the need to surgically open the knee joint.