Charcot joint is often known as Charcot foot, as the foot is the part of the body most likely to be affected, but it can also affect joints in the ankle, knee and, more occasionally, the wrist and hand. Charcot joint usually affects people who have had diabetes some 15 to 20 years and who are over the age of 50.
High blood glucose levels over a long period of time can lead to neuropathy (nerve damage), and this can lead to a loss of sensation in the foot. The motor nerves, responsible for movement, can also become damaged, and as a result the muscles may no longer be able to support the joint properly. Due to the lack of pain perception, minor injuries or traumas, such as a sprain, can go unnoticed and untreated. This can rapidly progress to a state where the joint becomes dislocated and deformed.
Early signs of an injury or trauma to the foot to watch out for include warmth, redness, a strong pulse and swelling around the foot and ankle. As Charcot joint develops, the joint can rapidly become dislocated, unstable or misaligned, leading to further swelling. Bony overgrowths (osteophytes) can also develop. All this can lead to severe deformity of the foot.
Charcot joint will often be apparent from a person’s medical history and symptoms, although x-rays or magnetic resonance imaging are also used to show misalignments and fractures within the joint. X-rays often show localised osteoporosis (loss of bone density) in the affected joint.
The earlier Charcot joint is detected, then the more effective treatment can be, minimising the risk of permanent deformity and of calluses (areas of hard, thickened skin) or ulcers forming. The joint must be stabilised and therefore rest is very important. Total contact casts or special boots may be required to help immobilise the joint. There is some evidence that bisphosphonates (a family of drugs used to prevent and treat osteoporosis) may help prevent further bone loss in the affected joint. In severe cases surgery may be necessary to reshape deformities and remove any bony overgrowths. People with charcot joint, or recovering from charcot joint, may require individualised footwear and will need to be referred to a NHS orthotist (someone who designs and fits special footwear).