16 Intersection Syndrome
Intersection syndrome (IS) is an overlooked cause of wrist pain. Pain in the wrist can be caused from many conditions including arthritis, tendonitis, ganglion cysts, and compressive neuropathies. IS is typically an overuse tendonitis of the wrist that is often confused with DeQuervain tendonitis as both pathologies affect the radial wrist and distal radial forearm. This chapter will review the history and potential causes of IS and explain the diagnosis and treatment options for this problem.
The symptoms of intersection syndrome (IS) were first discovered in 1841, however the phrase “intersection syndrome” was coined by Dobyns in 1978. This phrase refers to the condition caused at the area where the first dorsal extensor compartment crosses over or “intersects” the second dorsal extensor compartment. The intersection is at an angle of approximately 60 degrees. 1 This disorder has been referred to by various names such as peritendinitis crepitans, crossover syndrome, oarsman wrist, and squeakers wrist.
IS is classically a sports overuse injury that is seen with repetitive wrist extension and flexion. It has been reported in rowers, skiers, weight lifters, and other similar type sports. This can also occur with occupational and other daily use activities. The overall incidence varies and has been reported as high as 11.9% in skiers during the first 2 days of the ski season. 2 In the general population, ultrasound evaluation of the wrist in patients with wrist pain revealed an incidence of 1.9%. 3
There are two main theories as to the cause of inflammation for IS. The original hypothesis suggests the cause of inflammation is due to friction of the muscle bellies of the first dorsal compartment (extensor pollicis brevis [EPB], abductor pollicis longus [APL]) as they cross over the contents of the second dorsal compartment (extensor carpi radialis brevis [ECRB], extensor carpi radialis longus [ECRL) (► Fig. 16.1). 4 Another theory supports the idea of stenosing tenosynovitis of the second extensor compartment. Grundberg and Reagan intraoperatively discovered the pathologic abnormality as tenosynovitis in the second dorsal compartment. He found reliable improvement with decompression of this compartment. 5
16.4 Clinical Presentation
Patients present with pain approximately 4 to 8 cm proximal to the radial styloid with swelling along the dorsal radial aspect of the mid to distal forearm. There may be localized inflammation and point tenderness. The clinical hallmark of IS is painful, palpable, and audible crepitation (“wet rubber feel”) with active wrist flexion and extension. Symptoms worsen with heavy lifting and gripping activities.