Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Entrapment of the Ulnar Nerve (Ulnar Neuritis)

If the medial posterior aspect of the elbow is accidentally hit, pain can be felt radiating to the fourth and fifth fingers of the hand. The ulnar nerve runs along the medial edge of the elbow just behind the epicondyle to which the flexor muscles of the wrist are attached. In throwing or racket sports the nerve can be stretched or slid out of its groove with subsequent mechanical irritation.

The majority of nerve lesions in athletes can be described as neuro-praxia, the mildest form of nerve injury. It is characterized by a conduction block along a nerve where all nerve elements, axons, and
connective tissue remain in continuity. The prognosis for complete recovery may be good, provided no irreversible tissue damage has occurred due to long-standing compression.

The nerve can be injured by friction, compression, contusion, tension (traction), or a combination of these. The ulnar nerve is also susceptible to stretch injury, although it may stretch up to 20% before damage occurs. Valgus extension overload during serving and pitching creates significant tensile overload on the medial elbow ligament structures, and compressive loads laterally. The medial part of the ulnar nerve can elongate 0.2 in (4.7 mm) during extension to full flexion. It can be moved 0.3 in (7 mm) medially by triceps. These tensile loads also affect the ulnar nerve as it crosses through the cubital tunnel, causing nerve friction, irritation, and compression. The nerve may become unstable as the elbow is flexed.

Ulnar nerve entrapment was found in 60% of surgical cases of medial tennis elbow. These entrapments were found distal to the medial epicondyle at the medial and muscular septum, as the nerve enters the flexor carpi ulnaris. The nerve entrapment may be secondary to elbow instability, spurs, synovitis, and more proximal compression.

Symptoms and diagnosis

– Pain arises from the medial aspect of the elbow, typically after long tennis or golf matches, or throwing the javelin.
– Pain may increase and radiate to the fourth and fifth fingers of the hand.
– Numbness and impaired sensation may be present in the little finger and half the ring finger.
– Tenderness may occur over the nerve on the medial dorsal side of the elbow.
– In serious cases even tapping the ulnar nerve lightly can cause pain extending as far as the ring finger.
– Dislocation of the nerve from the cubital tunnel on palpation (that is, the nerve moves over the medial epicondyle during activity).

Treatment

The athlete should rest the arm.

The doctor may:
– prescribe anti-inflammatory medication;
– operate if the injury persists in order to free the nerve or move it to a position in which it is subjected to less tension. Surgery usually gives good results. In a chronic phase, especially if the nerve is subluxated,
the nerve can be treated surgically with transposition of the nerve in front of the epicondyle and decompression for at least 2 in (5 cm) distal to the epicondyle.

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