Intersection Syndrome

DEFINITION

Intersection syndrome is a tenosynovitis that primarily affectsthe radial wrist extensors. The condition is so named because symptoms present near the “intersection” of the extensor carpi radialis brevis(ECRB) and extensor carpi radialis longus(ECRL) muscles and the overlying muscle bellies of the extensor pollicis brevis (EPB) and APL.

SYNONYMS

• Tenosynovitis of the radial      wrist extensors

• Peritendinitis crepitans

• Subcutaneous perimyositis

• Crossover syndrome

• Oarsman syndrome

• Bugaboo forearm

• Squeaker’s wrist

Intersection-Syndrome

ETIOLOGY

• The EPB andAPL muscleslie dorsal to the tendons of the ECRB and ECRL approximately 4cm proximal to the carpal joint line

• This point lies just superior to Lister’s tubercle and is where the wrist and thumb tendons and muscles “intersect” or “crossover” each other

• Because of the close proximity, repetitive use of the wrist extensors can cause friction trauma to their synovial sheaths and concurrent irritation of the overlying EPB and EPL.

EPIDEMIOLOGY AND 

DEMOGRAPHICS

•Intersection syndrome is found about equally in males and females.

• Canoeists,skiers, and weightlifters have the highest incidence of the disorder.

MECHANISM OF INJURY

• Repetitive extension of the wrist as occurs in weightlifting, shoveling, rowing, and raking.

Intersection- Syndrome

• Intersection syndrome is also found in tennis players and downhill skiers who are inclined to “plant” or drag their ski poles in deep snow, thereby increasing resistance to wrist extension.

COMMON SIGNS AND 

SYMPTOMS

• Pain with thumb extension     and abduction.

• Pain with wrist extension

• Crepitus with wrist      movements

• Redness and edema

• “Squeaky” feeling during    wrist movements.

Intersection-Syndrome

AGGRAVATING ACTIVITIES

• Repeated wrist extension

• Repeated ulnar/radial deviation pronation,supination

• Pressure over the distal portion of the dorsal wrist and forearm

• Activities such as rowing, raking,shoveling,skiing, and weightlifting.

Intersection-Syndrome

EASING ACTIVITIES

• Rest and modified activities that decrease wrist extension and other wrist movements.

• Ice and elevation

24-HOUR SYMPTOM PATTERN

• Although there is no typical 24-hour variation in symptoms, the associated pain and swelling may increase throughout the day as a result of cumulative use.

• Early morning pain and swelling may result from immobility.

PAST HISTORY FOR THE REGION

• Recent increase in activities that involve resisted wrist movements

• Involvement in rowing,racket sports,or skiing

PHYSICAL EXAMINATION

• Palpation along the dorsal aspect of the wrist will reveal tenderness and swelling approximately 4cm distal to Lister’s tubercle.

• The pain of de Quervain’s syndrome will be localized more radially toward the base of the thumb.

•Guarding and pain may limit active and to a lesser extent passive movements of the wrist in all directions, especially in the sagittal plane.

Intersection-Syndrome

IMPORTANT OBJECTIVE TESTS

• First CMC grind test to rule out involvement of CMC

• Finkelstein’s test to rule out de Quervain’s syndrome

• Tinel’s test of the radial nerve to rule out Wartenberg syndrome

• Watson’s test (scaphoid  shift).

DIFFERENTIAL 

DIAGNOSIS

• De Quervain’s tenosynovitis

• Arthritis of the first CMC

• Fracture of radial styloid

• Fracture of the scaphoid or scapholunate separation

• Wartenberg syndrome.

CONTRIBUTING FACTORS

• Prior tendinopathies

• Preexisting circulatory problems

• Inflammatory disorders

• Advanced age.

SURGICAL OPTIONS

• Surgery is not necessary except in rare instances.

• The most common surgical option is a tenosynovectomy of the ECRL and ECRB.

• After tenosynovectomy, the thumb is placed in a volar spica splint for 1 to 2 weeks, and physical or occupational therapy is initiated.

• Surgery is usually an effective option when conservative treatments are not.

TREATMENT

REHABILITATION

• Use of modalities, heat, ice, and electrical stimulation to control swelling and pain.

• Splinting to facilitate healing and prevent exacerbation during the acute stages of healing (most commonly a spica splint with a bias toward 20 to 30 degrees of extension).

• 2 to 4 weeks of splinting will allow adequate healing in uncomplicated cases; however, healing depends on age and abstention from overuse of the wrist musculature.

• Focus of treatment should be regaining and maintaining ROM through passive and active movement of the thumb and wrist.

• As pain and symptomssubside,strengthening of the wrist and thumb should commence with isometrics,followed by gentle contractions against gravity with progression to very light resistance.

PROGNOSIS

• Typically, a 3-week course of splinting will lead to symptom resolution in 60% of patients.

• The majority of patients will find relief within a few months.

SIGNS AND SYMPTOMS 

INDICATING REFERRAL 

TO PHYSICIAN

• Lack of progress with conservative care

• Complications due to splint use

• Suspicion of an undiagnosed fracture.

SUGGESTED READINGS

1- Dobyns JH, Sim FH, Linscheid RL. Sports stress syndromes of the hand and wrist. Am J  Sports Med. 1978;6:236–254.

2- Hanlon DP, Luellen JR. Intersection syndrome: a case report and review of the literature.J Emerg Med. 1999;17(6):969–971.

3- de Lima J, Kim HJ, Albertotti F, Resnick D. Intersection syndrome: MR imaging with anatomic comparison of the distal forearm. Skeletal Radiol. 2004;33(11):627–631.

4- Pantukosit S,PetchkruaW,Stiens SA.Intersection syndrome in Buriram Hospital: a 4-yr prospective study. Am J Phys Med Rehabil2001;80(9):656–661. 

5- Parellada AJ, Gopez AG, Morrison WB, et al.Distal intersection tenosynovitis of the wrist: Radiol. 2007;36(3):203–208. Epub 2006 Dec 20.

6- Verdon ME. Overuse syndromes of the hand and wrist.Prim Care. 1996;23(2):305–319.