Bones and joints
In a small number of APS patients, the bones can be affected by a rather more acute condition known as avascular necrosis. Avascular necrosis is bone death caused by either permanent or temporary impairment of the blood supply; without blood, the bone tissue dies and, ultimately, the bone can disintegrate.
If the process involves bones near the joints, it often leads to the collapse of the joint surface. It is most common in the hips, but can also occur in other large joints such as the knee, elbow, wrist and ankle. Avascular necrosis is also known medically as osteonecrosis, aseptic necrosis and ischemic necrosis.
If avascular necrosis is not treated, the joint can deteriorate and cause severe arthritis. There are no symptoms in the early stages but, as the bone damage worsens, the person may feel pain in the affected area and the range of motion may be limited. If diagnosed early enough, treatment with anticoagulants can have a very positive affect in APS patients and slow the progress of the condition. However, if the avascular necrosis is fairly advanced, surgery may be necessary.
One study has also indicated that, in some APS patients, the bones in the feet, particularly the metatarsals, can spontaneously fracture due to impaired blood supply. Again, treatment with anticoagulants, was also shown to be effective in preventing further fractures.
Joint pain, known medically as arthralgia, is relatively common in APS patients. Arthralgia is less severe than full-blown arthritis, and tends not to be inflammatory in nature. Arthritis often occurs in other autoimmune conditions such as Sjogrens syndrome or lupus and can be treated with non-steroidal anti-inflammatory drugs (NSAIDs). However, this type of medication has little effect on arthralgia as the joint pain is not usually inflammatory, and it should be noted that NSAIDs should not be taken with warfarin, aspirin or clopidogrel. Instead, hydroxychloroquine has been found to be effective in reducing arthralgic pain for many people.