What is Intersection Syndrome?
Intersection Syndrome is a type of tenosynovitis that affects the thumb side of the forearm, resulting in pain to the lower forearm (usually a few inches from the wrist). The two muscles that control the thumb originate in the forearm, intersecting two wrist tendons before connecting to the thumb. Activities that involve frequent wrist movements can lead to inflammation of the tenosynovial lining that cover the tendons, known as tenosynovitis. Intersection Syndrome is sometimes confused with the more common De Quervain’s Tenosynovitis, which causes pain to the radial aspect of the wrist and forearm just below the thumb and closer to the hand.
What are the Causes of Intersection Syndrome?
Any activity that requires the wrist to repeatedly move downward toward the thumb, such as tennis, skiing, rowing and weight lifting can lead to Intersection Syndrome. This motion causes the muscles and tendons in the wrist to rub against one another, resulting in irritation and swelling. As the inflammation progresses, the tendons can no longer glide easily.
What are the Symptoms of Intersection Syndrome?
The most common symptom is pain to the wrist or forearm aggravated by flexion or extension. In addition, tenderness or swelling at the intersection point may be present. Occasionally, patients report squeaking or creaking (known as crepitus) with movement of the affected wrist.
How is Intersection Syndrome Treated?
Typically, a physical examination combined with a review of the symptoms can be used to diagnose Intersection Syndrome. Ultrasound or MRI may be used to assess the internal structures of the wrist if physical examination is inconclusive.
How is Intersection Syndrome treated?
Non-Surgical
As with most overuse injuries, the first course of action is to limit or eliminate the activities that cause symptoms. It is important to maintain a neutral alignment of the wrist and forearm whenever possible. A thumb-spica splint can help with this by immobilizing the lower thumb and wrist joints. Ice treatments and over-the-counter medications, such as aspirin and ibuprofen, can help reduce pain and inflammation.
If these interventions fail to adequately relieve symptoms, an injectable steroid such as cortisone may be used to decrease swelling and pain. Although cortisone is an extremely effective anti-inflammatory agent, the effects work best in the early stages of injury and is might be temporary or a cure.
Surgical
In the event that conservative treatments are not effective, surgery may be indicated to provide relief from symptoms. A minimally invasive tendon release operation can usually be performed on an outpatient basis. The procedure starts with a small incision over the intersection site to expose the involved muscles and tendons. Once the inflamed tendons are identified, the surgeon carefully removes the irritated tenosynovium and releases the tendon sheath. The skin is then sutured together and a surgical dressing is placed.
Rehabilitation generally consists of four to six weeks of physical or occupational therapy with full recovery in several months.