Acute Compartment Syndrome (ACS) is one of the few true emergencies in Orthopedic Surgery.
ACS is usually caused by trauma such as fractures or crush injuries. It involves excessive pressure within a muscular compartment. Normal resting muscle pressure is 12-20 mmHg. In compartment syndrome, the pressure rises to over 30mmHg and squeezes off the blood supply to the muscle, causing the muscle and the nerves that travel in that compartment to die. The condition is incredibly painful and if not treated with emergency surgery within 6 hours, the muscles and nerves die from lack of blood flow.
Acute Compartment Syndrome is most common in the lower leg, and in high energy injuries, but can also occur in the foot, the thigh, the forearm, and the hand. Compartment pressures can even cause an acute carpal tunnel syndrome by increased pressure following a wrist injury.
The injury is easily diagnosed by a standard clinical exam. The skin over the compartment will appear tight, shiny, and swollen. The most important sign is pain with passive stretch of the muscles. Knowing when the pain hurts from compartment syndrome and when it hurts from a fracture is the challenge—this is where it’s essential to have an experienced orthopedic surgeon taking care of you.
While an MRI can help, it is a waste of valuable time. MRIs are expensive tests that can take more than 2 hours to coordinate. In this condition, minutes count.
Some doctors use a pressure catheter inserted into the muscle compartment. These devices are tricky and inconsistent at times. If they are positive, you have your diagnosis, but a negative test is not reliable.
The condition is treated with emergent fasciotomy. Long relaxing incisions are made and the fascia (a layer of tissue beneath the skin and over the muscle) is released. The wounds are left open, and a wound vac (vacuum suction device) is placed over the open wounds. This encourages rapid resolution of swelling. Once the swelling is resolved, the wounds can be closed. Sometimes, the swelling is so great that skin-grafting is required.