Volkmann's contracture occurs when there is a lack of blood flow (ischemia) to the forearm. This usually occurs when there is increased pressure due to swelling, a condition called compartment syndrome.
Trauma to the arm, including a crush injury or fracture, can lead to swelling that presses on blood vessels and can decrease blood flow to the arm. A prolonged decrease in blood flow will injure the nerves and muscles, causing them to become stiff (scarred) and shortened.
When the muscle shortens, it pulls on the joint at the end of the muscle just as it would if it were normally contracted. But because it is stiff, the joint remains bent and cannot straighten. This condition is called a contracture.
In Volkmann's contracture, the muscles of the forearm are severely injured. This leads to contracture deformities of the fingers, hand, and wrist.
There are three levels of severity in Volkmann's contracture:
- Mild -- contracture of two or three fingers only, with no or limited loss of feeling
- Moderate -- all fingers are flexed and the thumb is stuck in the palm; the wrist may be stuck in flexion, and there is usually loss of some feeling in the hand
- Severe -- all muscles in the forearm that both flex and extend the wrist and fingers are involved; this is a severely disabling condition
The injury that usually causes this condition is an elbow fracture in children. Other conditions that can cause increased pressure in the forearm include:
- Animal bites
- Any forearm fracture
- Bleeding disorders
- Excessive exercise
- Injection of certain medications into the forearm