In patients with haemophilia who have limited access to replacement therapy, including regular prophylaxis, muscle function deterioration is present beyond structural joint damage and occurs very early in life.

Furthermore, despite effective prophylaxis and low bleeding rates, silent bleeds can still occur, triggering a biochemically and biomechanically vicious cycle, causing irreversible long-term joint damage. Much attention has been given to biochemical reactions, such as blood-induced inflammation and joint tissue damage, whereas biomechanical reactions occurring in the muscles and ligaments around the joint have been less studied, although they are equally important. Indeed, biomechanical reactions are the first to occur immediately after bleeding, as muscles react with changes in contraction and overloading ligaments, as demonstrated by analysing the three-dimensional movement of limbs in haemophilic patients. Therefore, early detection of muscle changes is critical to implement conservative preventive approaches.

Ankles and knees are the most frequently affected joints in haemophilia, and atrophy of neighbouring muscles is often noted, resulting in weakness during contraction. The quality of muscle contraction is altered in the vast majority of haemophiliacs, and the hamstring is often the most compromised muscle.

The Haemophilia Joint Health Score (HJHS) includes assessment of muscle trophism and strength of the ankles and knees; however, the hip joint and nearby muscles, such as the buttocks, are not included in this assessment.

Despite a similar HJHS, it appears that patients with frequent bleeding have a worse functional muscle outcome than those with less frequent bleeding treated on demand, suggesting the negative effect of repeated bleeds over time, which is usually the main trigger for implementing regular prophylaxis even in countries with limited resources.

Because impairment of function usually precedes structural damage, it is critically important in patients with haemophilia to include sensitive measuring instruments for more accurate musculoskeletal examination.

Furthermore, because loss of muscle function can be effectively treated with physical therapy or physician-supervised training, detection of muscle dysfunction should be implemented with training programmes to preserve the joints of patients with haemophilia from rapidly deteriorating.



  • Seuser A, Navarrete-Duran M, Auerswald G, Mancuso ME. Muscle function deterioration in patients with haemophilia: Prospective experience from Costa Rica. Haemophilia. 2018;00:1–12. https://doi. org/10.1111/hae.13455
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Learn more about the meaning of the words you read on this page and learn about the entire glossary on hemophilia.

A group of proteins with enzymatic functions involved in the clotting process.

All clotting factors are assigned a Roman numeral, although each one also has a proper name.

Some are produced by the liver, whereas others are synthesised by the endothelial cells that make up the inner lining of the blood vessels.

A protein belonging to the clotting factor category, a group of enzymes involved in the blood-clotting process.

It is encoded by a gene on the long arm of the X chromosome.

Factor VIII is also known as anti-haemophilic factor (AHF).

Product containing a high concentration of freeze-dried factor VIII, used for replacement therapy in the treatment of haemophilia A.

A ereditary genetic illness, characterised by a deficiency of clotting factor VIII, that exposes the individual to a greater risk of both internal and external bleeds.

Haemophilia A is more common in males, whereas females tend to be healthy carriers of the condition.

The typical symptoms of the condition include haemarthroses (joint bleeds) and haematomas (muscle bleeds).

Damage that occurs in the joints and prevents their normal function, thereby impairing the individual’s ability to move normally. In haemophiliac patients, joint disease is usually the consequence of recurrent haemarthroses.

Condition that occurs when factor VIII activity is between 1% and 5%.

Condition that occurs when factor VIII activity is between 1% and 5%.

Condition that occurs when factor VIII activity is <1%.