Kaneko, S., & Takasaki, H. JOSPT. 2011; 41(7): 514-519 Article summary by Matthew Reinagel SPT, from Missouri State University, Springfield, Missouri

This case series involved five female patients (mean age 49.4 years) referred to physical therapy with the diagnosis of intersection syndrome. Intersection syndrome is an overuse injury of the distal forearm that causes pain, crepitus, and swelling in the forearm where the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) cross the underlying extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) tendons. Common treatments for intersection syndrome include wrist splinting, rest, NSAIDs, or steroid injections.

The symptoms recorded in this study included crepitus induced by active thumb movements, visual swelling of the forearm, and tenderness over the dorsal forearm rated 3 or above on a scale of 0 to 10. Each patient received a diagnosis from an orthopedic surgeon through the use of an MRI that showed swelling around the first and second extensor compartment tendons that extended proximally from the intersection of the four muscles primarily involved in intersection syndrome. Diagnoses were also made using special tests, such as Finkelstein’s test, isometric muscle testing of the APL, EPB, ECRL, and ECRB muscles, Tinel’s sign, upper limb neurodynamic tests, and the overall clinical presentation.

The symptoms first had to be differentiated between De Quervain’s disease and intersection syndrome. Finkelstein’s test (normally performed to diagnose De Quervain’s disease), was positive for each patient. Pain was also provoked by isometric testing of the ECRL and ECRB muscles, but not for the APL or EPB, suggesting intersection syndrome rather than De Quervain’s disease. The tenderness was along the posterior aspect of the arm instead of the lateral arm, further pointing towards intersection syndrome. The crepitus with thumb movements was found at the intersection of the four muscles mentioned above rather than over the first dorsal compartment or at the styloid process of the radius commonly seen with De Quervain’s disease. Also, Tinel’s sign and upper limb neurodynamic tests were negative.

Each patient in this study presented with decreased active and passive flexion in the MCP joint of the thumb and decreased active wrist extension and passive wrist flexion. The most painful activity (at least an 8/10) for each patient was anything from squeezing to transferring to cooking. The patients also filled out the Japanese version of the Disabilities of the Arm, Shoulder and Hand (DASH) Questionnaire. Each patient received a taping intervention to treat the symptoms in the affected forearm. The distal end of the 50mm-wide non-stretch tape was applied to the muscle bellies of the APL and EPB. The tape was then pulled across the dorsal forearm perpendicular to the long axis of the arm (in the direction that eliminated crepitus),and a second layer was applied in the same direction.

The patients were educated in self-application of the tape and were told to only remove the tape at night and to maintain the taping regimen for 3 weeks. Patients were also instructed to use the symptomatic limb in activities of daily living and to work without the tape following the 3-week treatment period.

The presence or absence of crepitus, swelling, and tenderness was assessed at the initial consultation, at the 1-week, 2-week, 3-week, and 4-week follow-ups and after 1 year. All the patients experienced crepitus, swelling, and tenderness at the initial consultation. At each subsequent follow-up, patients’ symptoms decreased. By the 3-week follow up, the crepitus (the main reason for the intervention) and all the other symptoms were eliminated. These symptoms remained absent on the 4-week and 1-year follow ups.

The DASH Questionnaire was completed at the initial consultation, at the 1-week, 2-week, 3-week, and 4-week follow-ups and after 1 year. A considerable improvement in DASH score was seen in each patient by the week-3 follow-up, and the scores remained the same for the 4-week and 1-year follow-ups.

The authors concluded that taping may be beneficial for the management of intersection syndrome. All patients experienced a rapid improvement in upper extremity function after the application of tape. A cause-and- effect relationship cannot be found with this study, however, even with the positive effects of taping. It is still questionable whether taping can alter soft tissue alignment. An MRI would be needed to determine whether the taping provided in this study actually altered the alignment of the APL, EPB, ECRL, and ECRB tendons. Also, more research is needed with more subjects to determine the effects of taping on intersection syndrome. Another downfall of this study is the absence of an intervention to compare taping to, such as splinting. The authors of this study did not compare different types of tape to determine which tape might be best for this intervention.

Personal Commentary:

This case was chosen due to the uncommon pathology presented. I have seen one patient with this diagnosis at an occupational medicine clinic. Before this patient, I had never come across this pathology and have yet to see it resurface again in my limited time in the clinic. We treated this patient with hand strengthening exercises, soft tissue massage, cross-friction massage and modalities such as heat, e-stim, and ultrasound during the patient’s therapy sessions. The soft tissue work tended to improve the patient’s symptoms, but unfortunately, taping was not used as an intervention. It would have been interesting to use the knowledge I have from reading this article in order to apply it to this patient.

The symptoms, compared to those of De Quervain’s or other forearm pathologies, are quite clear. I do wonder if intersection syndrome is commonly misdiagnosed in due to its similarity to De Quervain’s syndrome. Additionally, with the increased use of technology in the U.S, wrist pathologies due to overuse will surely be on the rise. Therefore, future studies should be done to determine the best treatments for conditions such as intersection syndrome.

References:

1. De Lima, J., Kim, H., Albertotti, F. & Resnick, D. Intersection Syndrome: MR Imaging with Anatomic Comparison of the Distal Forearm. Skeletal Radiology. 2004; 33: 627-631/

2. Hanlon, D.P., & Luellen, J.R. Intersection Syndrome: A Case Report and Review of the Literature. Journal of Emergency Medicine. 1999; 17: 969-971

3. Larsen, B., Andreasen, E., Urfer, A., Mickelson, M.R. & Newhouse K.E. Patellar Taping: A Radiographic Examination of the Medical Glide Technique. American Journal of Sports Medicine. 1995; 23: 465-471.

4. Servi, J.T. Wrist Pain from Overuse: Detecting and relieving Intersection Syndrome. The Physician & Sports Medicine. 1997; 25: 41-44.

IAOM Comment:

The unique anatomical feature about the structures involved in Intersection Syndrome is that the musculotendinous junctions of the involved muscles are also covered by synovial sheaths at this level. As a result, clinical testing will be painful with both resisted testing, and stretch, AND the patient will complain of crepitice. Long ago, one of my IAOM mentors said, ‘what you don’t know, you don’t see.’ Being aware of this kind of forearm pathology will allow you to recognize it in the clinical setting, as well as in your friends and family who very often become overwhelmed by visits to their provider or the local urgent care center and are told ‘we don’t know what this is.’ It almost always has an ‘uncommon repeated activity as a causal event, and it can be exquisitely painful and swollen. With such a clear clinical picture, MRI is not needed.

As noted above, conservative treatment – with the addition of taping – can provide successful outcomes generally within two weeks. Perhaps taping alone will take longer. This pathology and recommended management is taught in the IAOM-US Diagnosis and Management of the Wrist and Thumb course.

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