Clinical History
A 13-year-old boy came to the emergency department with swelling and marked local inflammation of the right knee lasting for one week.
His father referred a history of haemophilia with recurrent episodes of right knee swelling and also a previous surgery (1 year ago).
Imaging Findings
Initially plain films of the knee were obtained. These showed widening and erosion of intercondylar notch, enlargement of distal femoral epiphysis and flattening of distal femoral condyles. There was also an irregularity of the articular surfaces and subchondral sclerosis. Peri-articular density was present in such an extent that a huge soft tissue mass resulted (“haemophiliac pseudotumour”).
The patient then had a knee Ultrasonography to evaluate the intra-articular contents and ecogenicity of the soft tissue mass. It revealed a mixed echogenicity content in the medial and lateral recesses of the knee and in the subquadricipital recess. There was also significant Doppler signal. These findings were related to haematoma and inflammatory activity. There was also oedema of the subcutaneous tissues.
A MR study was performed one week later. It showed heterogeneous signal intra-articular content, multiple bone erosions and an osteochondral lesion in the medial condyle.
Discussion
This 13-year-old boy had swelling and marked local inflammation of the right knee lasting for one week. His clinical history included a previous right knee sinovectomy and Haemophilia A.
Haemophilia A results from a lack of clotting factor VIII. It is a sex-linked disease, making women asymptomatic carriers [1].
The most typical manifestation of haemophilia is haemarthrosis [2]. When haemarthrosis becomes frequent and/or intense, the synovium may not be able to reabsorb the blood. To compensate for such reabsorptive deficiency, the synovium will hypertrophy, resulting in what is called chronic haemophilic synovitis (in approximately one half of the patients) [3]. The synovitis, along with the ferritine deposition in the hyaline cartlilage leads to sloughing of the cartilage and thus secondary osteoarthritis. Patients develop chronic deformities in one or more joints, which clinically and roentgenographically resemble rheumatoid arthritis [4]. There is marked synovial membrane hyperplasia, destruction of articular cartilage, and erosions of subchondral bone [3].
An abnormally increased vascularity around the epiphysis can occur in certain inflammatory conditions, such as chronic haemophilic synovitis. This can cause growth disturbance with a premature elongation of the bone [2]. Overgrowth of the femoral condyles leads to widening of the intercondylar notch, and overgrowth of the patella causes the appearance of squaring of its inferior pole [3].
Further, as patients age, the recurrent bouts of inflammation ultimately lead to premature closure of the patient’s physeal plates around the affected joint. This means that, once the patient reaches adulthood, an affected leg may be shorter than an unaffected leg. If the epiphyses close unevenly, the joints may also develop deformities [2].
Thus, it is very important not only to avoid acute haemarthrosis, but also to manage it as efficiently as possible, in order to avoid the development of synovitis [4].
Haematological prophylactic treatment from the age of two to the end of skeletal maturity is the best way to avoid articular bleeds, or at least to diminish their intensity [4]. In cases of well established arthropathy, sinovectomy is often necessary to stop rapidly advancing osteoarthritis [5].
Differential Diagnosis List
Haemophilic arthropathy and hemarthrosis
Juvenile rheumatoid arthritis (plain film)
Pigmented villonodular synovitis (MRI)
Final Diagnosis
Haemophilic arthropathy and hemarthrosis
