Hemarthrosis is a medical condition defined by the presence of blood within a joint cavity, also known as the synovial space. This accumulation of blood creates a hemorrhagic effusion, which disrupts the normal environment and function of the joint. The knee is the most commonly affected joint, though it can occur in the ankle, elbow, hip, or shoulder. Hemarthrosis requires immediate medical evaluation and treatment to prevent long-term damage to the joint structures.
Identifying the Acute Symptoms
A person experiencing hemarthrosis typically notices a rapid and severe onset of symptoms immediately following an injury or spontaneous bleed. The sudden accumulation of blood causes intense, throbbing pain, which is often the first and most alarming sign, resulting from increased pressure within the joint capsule. A rapid swelling, or effusion, follows quickly, often developing within a few hours. The affected joint will feel noticeably warm to the touch, and the skin overlying the area may appear reddened due to internal inflammation. Movement becomes significantly limited, resulting in an inability to fully extend or bend the joint.
Traumatic and Non-Traumatic Causes
The etiology of hemarthrosis is broadly separated into cases resulting from an external force and those arising from systemic issues within the body. Traumatic hemarthrosis is the most frequent cause, resulting from acute mechanical injury that damages blood vessels inside or around the joint. Common examples include severe sports injuries, such as an anterior cruciate ligament (ACL) rupture in the knee, which causes immediate and profuse bleeding. An intra-articular fracture, where a bone break extends into the joint surface, can also lead to hemarthrosis by allowing blood and fatty marrow to leak into the synovial space. Damage to the menisci or other severe contusions can also compromise the vascular structures surrounding the joint.
Non-traumatic, or systemic, causes often involve an underlying disorder that impairs the body’s natural clotting mechanism. The most recognized of these is hemophilia A or B, genetic conditions characterized by a deficiency in clotting Factor VIII or Factor IX, respectively. In these individuals, even minor stress or a spontaneous event can trigger a joint bleed. Acquired conditions, such as the use of anticoagulant medications like warfarin, can also predispose an individual to hemarthrosis. Less common causes include certain inflammatory arthropathies, advanced liver or renal disease that impairs the production of clotting factors, or the presence of a tumor near the joint.
Medical Confirmation and Initial Stabilization
Medical professionals rely on a combination of imaging and a definitive procedure to confirm hemarthrosis and assess the extent of the injury. Initial imaging typically includes X-rays to check for any associated fractures, especially those that extend into the joint space. More detailed imaging, such as a magnetic resonance imaging (MRI) scan, may be used to evaluate soft tissue structures like ligaments, tendons, and cartilage for damage.
The definitive diagnostic method is an arthrocentesis, which involves inserting a sterile needle into the joint space to aspirate, or withdraw, the accumulated fluid. The presence of gross blood confirms the diagnosis of hemarthrosis. Analyzing this fluid can also distinguish between simple blood and lipohemarthrosis, which is the presence of both blood and fat globules and strongly indicates an intra-articular fracture. During the acute phase, initial stabilization focuses on reducing pressure, swelling, and pain. This often involves the use of the RICE protocol: rest, ice application to the joint, compression, and elevation of the affected limb. In cases of significant swelling and pressure, the arthrocentesis procedure itself provides immediate therapeutic relief by draining the excess blood.
Treatment and Preventing Joint Damage
Treatment is highly dependent on the underlying cause of the bleeding, and addressing this cause is paramount to preventing recurrent episodes. For individuals with hemophilia, the standard treatment involves prompt administration of the deficient clotting factor concentrate to stop the bleed internally. This factor replacement therapy must be given quickly, ideally within two hours of the onset of symptoms, to minimize joint exposure to blood.
For traumatic hemarthrosis, treatment may involve surgical intervention to repair damaged structures, such as a torn ligament or an unstable fracture. Once the acute bleed is controlled and the joint is stabilized, a program of physical therapy begins. Rehabilitation focuses on restoring the joint’s full range of motion and strengthening the muscles surrounding the joint to provide long-term stability. Untreated or repeated hemarthrosis can lead to significant and permanent joint deterioration, a condition known as hemophilic arthropathy. The presence of blood within the joint space is toxic to the cartilage, initiating an inflammatory process that damages the joint surface. Adherence to treatment protocols is necessary to protect the cartilage and prevent the development of early-onset osteoarthritis and long-term disability.