December 26, 2021
Cubital tunnel syndrome cover

A Review of Cubital Tunnel Syndrome

Cubital Tunnel Syndrome, sometimes called Sulcus Ulnaris Syndrome or Retrocondylar Groove Syndrome, is a compressive neuropathy of the ulnar nerve most commonly at the level of the cubital tunnel. It was first described by Magee and Phalen in 19449.[1]Magee RB, Phalen GS. Tardy ulnar palsy. Am J Surg 1949;78:470–4 It is the second most common neuropathy of the upper extremity behind carpal tunnel syndrome, and the most common location for compression of the ulnar nerve.[2]Bozentka DJ. Cubital tunnel syndrome pathophysiology. Clin Orthop Relat Res 1998;351:90 –94 The incidence is approximately 24.7 per 100,000 people, more common in males and bilateral about 20-30% of the time.[3]Artico M, Pastore FS, Nucci F. et al . 290 surgical procedures for ulnar nerve entrapment at the elbow: physiopathology, clinical experience and results. Acta Neurochir. 2000; 142 303-308

Image 1. Basic illustration of the cubital tunnel.

The ulnar nerve courses posterior to the medial epicondyle, and olecranon before entering the cubital tunnel. Distal to the cubital tunnel, it courses deep into the forearm between the ulnar and humeral heads of the flexor carpi ulnaris. The etiology can loosely be broken down into primary or idiopathic, which is most common, or secondarily due to some deformity or other process of the elbow. The most common location is the cubital tunnel, but compression can also occur at the deep flexor pronator aponeurosis, Arcade of Struthers, or Osborns ligament. Less commonly, other locations include the medial intermuscular septum, medial epicondyle, hypertrophy of the medial head of the Triceps Brachii, fascial bands within FCU, accessory anconeus epitrochlearis muscle, or aponeurosis of FDS proximal edge.

Image 2. Osteophyte formation, joint space reduction and ossified bodies (changes of degenerative disease) are seen in a patient with cubital tunnel syndrome.[4]Case courtesy of Dr Maulik S Patel,, rID: 23923

Image 3. Cubital tunnel syndrome due to snappiing triceps. Axial T1-weighted MR image with elbow extended shows the ulnar nerve (arrowhead) and the medial triceps (arrow) posterior to the medial epicondyle (*)

The diagnosis can typically be made clinically. Onset is often acute or subacute with paresthesia in an ulnar nerve distribution. Pain is not common, but vague discomfort can occur in the medial elbow and forearm. There may be difficulty with certain activities like opening doors or jars or with repetitive activity. Symptoms are worse at night. On exam, there may be weakness in the intrinsic muscles of the hand, especially the 4th and 5th digit. In chronic cases, atrophy may be noted. Potentially positive special tests include tinels testthe elbow flexion compression test, and scratch testFroments sign (inability to grip a piece of paper between the thumb and index finger) and wartenbergs sign (exaggerated abduction of the 5th digit compared to the unaffected limb) may be present. Additional signs suggesting ulnar neuropathy include jeanne sign, masse sign and pollocks test.

Diagnostics can be useful to help support the working diagnosis. Radiographs are typically normal, but may see osteophytes or spurring in chronic cases. MRI may sho ulnar nerve thickening, T2 hyperintensity and edema-like signal changes. [5] Ultrasound can show a hypoechoic nerve, with thickening defined as > 9 mm and edematous changes.[6]Choi SJ, Ahn JH, Ryu DS, Kang CH, Jung SM, Park MS, Shin DR. Ultrasonography for nerve compression syndromes of the upper extremity. (2015) Ultrasonography (Seoul, Korea). 34 (4): 275-91. … Continue reading Electromyography and nerve conduction study can be useful to confirm the diagnosis and exclude other etiologies, especially when surgery is being considered. Findings include decreased absolute conduction velocity and a relative drop in conduction velocity across a segment.

Image 4. Cubital tunnel nerve glide exercises.[7]Image courtesy of, “CUBITAL TUNNEL ULNAR NERVE GLIDING EXERCISES”

Management is non surgical in almost all cases. Often activity modification alone can improve symptoms and this includes avoiding certain positions in elbow flexion resting on a hard surface. [8]Kroonen, Leo T. “Cubital tunnel syndrome.” Orthopedic Clinics 43.4 (2012): 475-486. An elbow flexion block splint with the elbow braced at 45 degrees extension with forearm in neutral position can help. Physical therapy, especially nerve glide exercises, has been shown to help. [9]Bryon PM. Upper extremity nerve gliding: programs used at the Philadelphia Hand Center. In: Hunter JM, Mackin EJ, Callahand AD, editors. Rehabilitation of the hand: surgery and therapy. 4th edition. … Continue reading Surgery is indicated when conservative therapy fails and may include in situ decompression, medial epicondylectomy, endoscopic cubital tunnel release and anterior transposition.
There are no evidence based guidelines for return to play but most athletes can return when symptoms improve or resolve. Prognostically, about 90% of patients have improvement with conservative management at 3 months. [10]Svernlov B, Larsson M, Rehn K, et al. Conservative treatment of the cubital tunnel syndrome. J Hand Surg Br 2009;34:201–7. Complications include injury to the medial antebrachial cutaneus nerve, recurrence of symptoms or ulnar nerve neuroma.

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