High Yield Topics

Cubital Tunnel Syndrome

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Cubital Tunnel Syndrome
Jeffrey Rosenberg
Thomas A. Phipps
Basics
  • Compression, traction, or irritation of the ulnar nerve as it passes through the cubital tunnel of the medial elbow
  • The cubital tunnel is bounded by the medial trochlea, the medial epicondylar groove, and the posterior portion of the ulnar collateral ligament and is roofed by the triangular arcuate ligament.
  • Primary complaints are medial elbow and forearm pain.
  • Additional complaints are paresthesias in the ring and little fingers.
  • Synonym(s): Ulnar tunnel syndrome
Epidemiology
Incidence
  • The elbow is the most common site of compression of the ulnar nerve.
  • Predominant gender: Male > Female (3–8:1)
  • The 2nd most common compressive neuropathy (after carpal tunnel syndrome)
  • Overhead throwing athletes are most at risk.
Risk Factors
  • Overhead throwing athletes
  • Repetitive upper extremity activities
  • Diabetes
  • Obesity
  • Peripheral neuropathies
General Prevention
Avoid prolonged pressure on the medial elbow.
Etiology
Possible causes of the compression of the ulnar nerve as it passes the medial elbow include:
  • Subluxation of the ulnar nerve over the medial epicondyle
  • Enlarged medial head of the triceps muscle
  • Cubitus valgus
  • Ulnar collateral ligament instability/tears
  • Triangular arcuate ligament tears in baseball pitchers
  • Osteophytes
  • Ganglia or lipomas
  • Tumors
  • Repetitive elbow flexion and extension
  • Anconeus epitrochlearis: Anomalous muscle in 70% of population
Commonly Associated Conditions
  • Ulnar neuritis
  • Ulnar collateral ligament instability
Diagnosis
History
  • Vague, aching pain in the region of the elbow, worsening with overhead activities
  • Paresthesias over the 4th and 5th digits
  • Numbness of the 4th and 5th digits
  • Weakness of interosseous muscles of the hand
  • Worsening grip and clumsiness
  • Snapping or popping sensation of medial elbow
  • Overhead throwing athletes will complain of loss of control of ball with activity.
Physical Exam
  • Pain with palpation of cubital tunnel of affected elbow
  • Positive Tinel sign: Tapping over the ulnar nerve at the elbow will cause a reproduction of symptoms (1).
  • Elbow flexion test: Placing the elbow in full flexion and the wrist in maximal extension will cause pain or paresthesias after 1 min (1).
  • Scratch test: Patient faces examiner with arms adducted, elbows flexed, and hands outstretched with wrists in a neutral position. Patient resists adduction/internal rotation to the forearms applied by the examiner. The examiner scratches or wipes fingertips over the cubital tunnel, and resistance to adduction/internal rotation is again applied. In a positive test, the patient has immediate and temporary loss of external resistance tone, which resolves within 5 sec (1).
  • Sensory changes in ulnar nerve distribution can be detected with Semmes-Weinstein monofilament testing and, in more advanced cases, with 2-point discrimination tests.
  • Asymmetric hypothenar atrophy, decreased pinch and grip strength, abducted little finger, or severe claw deformity of little finger only (Wartenberg sign)
  • Intrinsic muscle weakness and wasting (especially 1st dorsal interosseous muscle)
  • Patient will exhibit decreased sensation in the ulnar nerve distribution.
Diagnostic Tests & Interpretation
  • Complete medical history and physical exam
  • Nerve conduction velocity (NCV) to determine how fast neurologic signals travel down nerve to detect site of compression or constriction. Studies must be performed with elbow at 45 degrees of flexion to lessen chance of erroneous results (2).
  • Electromyogram (EMG) to evaluate nerve and muscle function
Imaging
  • Radiograph of elbow to evaluate for bony changes or spurs
  • MRI of elbow to evaluate cubital tunnel for soft tissue masses and continuity of ulnar collateral ligament
  • Diagnostic US: Ratio of ulnar nerve cross-sectional area at maximal enlargement to cross-sectional area at unaffected site >2.8:1; ratio in control subjects 1.1:1 (3)
Pathological Findings
  • At decompression, specific sites of nerve compression usually can be found.
  • Inspect the arcade of Struthers, intermuscular septum, cubital tunnel, and Osborne fascia (between 2 heads of flexor carpi ulnaris).

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Differential Diagnosis
  • Systemic: Diabetes, renal disease, multiple myeloma, amyloidosis, chronic alcoholism, malnutrition
  • Compression: Postoperative occupational or recreational activities requiring repetitive flexion and extension, supracondylar process, ligament of Struthers, medial head of triceps, ulnar nerve compression at Guyon canal
  • Medial epicondylitis
  • Ulnar collateral ligament injury
  • Cervical radiculopathy
  • Thoracic outlet syndrome
  • Carpel tunnel syndrome
Treatment
  • Conservative treatment is effective in up to 90% of patients irrespective of EMG/NCV results (4,5,6,7).
  • The most effective treatment is cessation of activity that is causing the problem.
  • A splint or foam elbow pad worn at night (to limit movement and reduce irritation)
  • Elbow pad (to protect against chronic irritation from hard surfaces)
  • NSAIDs
  • Physical therapy with attention to nerve-gliding exercises
Surgery/Other Procedures
  • Consider surgery if symptoms continue after 3 mos of conservative therapy or multiple recurrences in a throwing athlete (8,9,10).
    • Address ulnar collateral ligament instability if coexisting.
    • Decompression of the nerve in the canal, especially in setting of bone spurs
    • Transposition of the nerve out of the canal in an anterior direction
  • Multiple meta-analyses have been inconclusive and differ in results; none specifically for athletes (11,12,13).
    • No clinical or NCV differences between simple compression and ulnar nerve transposition
    • No statistically significant difference but rather a trend toward improved clinical outcomes with transposition of the ulnar nerve (combining 2 types of transposition) compared with simple decompression
  • Preference for overhead athlete is transposition of the ulnar nerve to allow for improved movement of the nerve throughout the range of motion (8).
    • Subcutaneous technique: Anterior transposition of nerve without detachment of flexor mass; fascial sling used to prevent subluxation of nerve
    • Submuscular technique: Allows inspection and treatment of ligament and osseous pathology; nerve stabilized deep to flexor-pronator muscles but more morbidity and potential for deep scarring
References
1. Cheng CJ, Mackinnon-Patterson B, Beck JL, et al. Scratch collapse test for evaluation of carpal and cubital tunnel syndrome. J Hand Surg [Am]. 2008;33:1518–1524.
2. Sattari S, Emad M. Changes in ulnar nerve conduction velocity across the elbow in different angles of elbow flexion. Electromyogr Clin Neurophysiol. 2007;47:373–376.
3. Yoon JS, Walker FO, Cartwright MS. Ultrasonographic swelling ratio in the diagnosis of ulnar neuropathy at the elbow. Muscle Nerve. 2008.
4. Szabo RM, Kwak C. Natural history and conservative management of cubital tunnel syndrome. Hand Clin. 2007;23:311–318, v–vi.
5. Svernlov B, Larsson M, Rehn K, et al. Conservative treatment of the cubital tunnel syndrome. J Hand Surg Eur Vol. 2009.
6. Gellman H. Compression of the ulnar nerve at the elbow: cubital tunnel syndrome. Instr Course Lect. 2008;57:187–197.
7. Padua L, Aprile I, Caliandro P, et al. Natural history of ulnar entrapment at elbow. Clin Neurophysiol. 2002;113:1980–1984.
8. Bencardino JT, Rosenberg ZS. Entrapment neuropathies of the shoulder and elbow in the athlete. Clin Sports Med. 2006;25:465–487, vi–vii.
9. Keefe DT, Lintner DM. Nerve injuries in the throwing elbow. Clin Sports Med. 2004;23:723–742, xi.
10. Charles YP, Coulet B, Rouzaud JC, et al. Comparative clinical outcomes of submuscular and subcutaneous transposition of the ulnar nerve for cubital tunnel syndrome. J Hand Surg Am. 2009;34:866–874.
11. Mowlavi A, Andrews K, Lille S, et al. The management of cubital tunnel syndrome: a meta-analysis of clinical studies. Plast Reconstr Surg. 2000;106:327–334.
12. Zlowodzki M, Chan S, Bhandari M, et al. Anterior transposition compared with simple decompression for treatment of cubital tunnel syndrome. A meta-analysis of randomized, controlled trials. J Bone Joint Surg Am. 2007;89:2591–2598.
13. Macadam SA, Gandhi R, Bezuhly M, et al. Simple decompression versus anterior subcutaneous and submuscular transposition of the ulnar nerve for cubital tunnel syndrome: a meta-analysis. J Hand Surg [Am]. 2008;33:1314.e1–1314.e12.
Additional Reading
Cuts S. Cubital tunnel syndrome. Postgrad Med. 2007;83(975):28–31.
Mowlavi A, et al. The management of cubital tunnel syndrome: a meta-analysis of clinical studies. Plast Reconstr Surg. 2000;106:327.
Codes
ICD9
354.2 Lesion of ulnar nerve
Clinical Pearls
  • Most important part of treatment is to minimize elbow flexion and pressure on the elbow and to engage in relative rest from repetitive activity.
  • Screen overhead athletes for ulnar collateral ligament instability.


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