On the wrist and forearm above the thumb, two tendons (abductor pollicis longus and extensor pollicis brevis) cross over another set of two tendons (extensor carpi radialis longus and brevis) and as such, they intersect each other. They are the movers of the thumb and the wrist.
Pain, swelling and redness may occur at the intersection. Squeaking may be heard as the tendons attempt to move against one another. Pain can spread down to the thumb or up along the forearm.
What causes an intersection syndrome?
Overuse of the wrist and thumb from wringing, grasping, turning and twisting motions eventually causes irritation of these tendons. Most of the cases involve a combination of heavy and repetitive use of the wrist and thumb.
Resting the sore area will prevent further injury while allowing time to heal. A splint is used to rest the thumb and the wrist. Pain with activity is a sign that irritation is occurring. Avoid movements and activities that increase pain.
Take frequent breaks or limit the amount of time you are performing tasks that require repetitive wringing, grasping, turning and twisting type movements of the wrist.
Antiinflammatory medications work well in conjunction with rest. In more refractory cases an injection of cortisone between the two sets of tendons may give relief. Most cases of Intersection Syndrome can be successfully treated with these modalities.
Surgery is rarely necessary in this condition. In extremely refractory cases of Intersection Syndrome surgical release of the tendons may be indicated.