Ulnar neuritis (cubital tunnel syndrome)

What is cubital tunnel syndrome?

Cubital tunnel syndrome is a condition in which the ulnar nerve, under the medial (inside) aspect of the elbow (the “funny bone”) becomes irritable, causing symptoms of pain, numbness tingling and, sometimes, weakness into the ulnar (little finger aspect) side of the hand.

It is known as cubital tunnel syndrome because it occurs due to compression or entrapment or irritation of the nerve within the confines of a space called the cubital tunnel, just behind the bony prominence on the inside (medial aspect) of the elbow. It is also known as ulnar neuritis, derived from neur-, meaning nerve, and –itis, reflecting inflammation. Ulnar nerve dysfunction or inflammation may greatly decrease athletic performance in sports that require strong hand or wrist actions.

How does cubital tunnel syndrome occur?

Most commonly, neuritis is due to some irritation, compression or stretching of the ulnar nerve within the relatively restricted confines of the cubital tunnel through which it travels. The nerve is vulnerable within this space for a number of reasons:

•  The space itself is relatively confined, with little room to accommodate any soft tissue swelling

•  The surrounding soft tissue envelope provides little protection and is thus at risk from trauma such as a direct blow during contact sports (like football or rugby)

•  In some cases (up to 17 percent) of the population, the nerve can actual be “unstable,” i.e., the nerve can actually move back and forth across the medial side of the elbow (the medial epicondyle), leading to repetitive stresses within the nerve. In an athlete performing repetitive overhead activity (baseball pitcher, tennis player, weight lifter), this can lead to neuritis as well.

•  Laxity of the elbow’s medial (inside) ligament can also result in increased forces on the ulnar nerve, causing symptoms

Some patients have insidious onset of symptoms without identifiable cause.

What increases the risk?

•  Athletic activities involving forceful and usually repetitive “overhead” type of motions, such as the baseball pitch, javelin throw or tennis serve

•  Contact and collision sports, particularly those in which the elbow is insufficiently padded (such as football and rugby)

•  Failure to properly warm-up, stretch or be appropriately conditioned, and subjecting the elbow to considerable demands

What are the symptoms of cubital tunnel syndrome?

•  Sense of numbness, tingling or radiating discomfort down the ulnar side (inside aspect) of the forearm or into the little and ring fingers

•  Occasional pain, discomfort or aching within the area of the cubital tunnel itself

•  Sense of hand weakness or clumsiness

•  Loss of normal sense of finger dexterity, grip strength and control

•  Compromised athletic performance (decreased throwing or serving velocity or accuracy, decreased weight-lifting ability)

How is cubital tunnel syndrome diagnosed?

Diagnosis is based on history and physical exam, occasionally complemented by a nerve study known as an EMG. Important components of the history are the symptoms listed above, most commonly discomfort, burning along the inside of the elbow and/or numbness and tingling in the little and ring fingers, particularly associated with provocative athletic activities (such as throwing for a baseball pitcher or serving for a tennis player)

Typical physical exam findings include:

•  Discomfort or tenderness to palpation (touch) over the cubital tunnel

•  A positive “Tinel’s” sign, in which light tapping over the course of the nerve within the tunnel elicits (and typically reproduces) the patients’ symptoms of referred pain, numbness and tingling, often in the little and ring fingers

•  Decreased sensation to light touch in the distribution of the nerve (little and ring fingers)

Possible “instability” of the ulnar nerve, in which the nerve can actually be felt to “move” back and forth over the medial (inside) aspect of the elbow bone (medial epicondyle)

•  A weak grip, especially power grip, and a weak pinch

Are there any special tests?

•  The most common tests are nerve diagnostic tests known as EMG/NCV.

•  An EMG stands for Electromyography. Very much like an EKG (electrocardiograph), an EMG measures the electrical activity in muscles of the upper extremity. In cases of significant neuritis, the muscles to which the nerves travel can demonstrate “irritability, confirming the likely problem within the nerve itself. EMG changes are uncommon in ulnar neuritis, since most patients have this condition occur only during activity, rather than at rest.

•  A more commonly performed diagnostic test is the NCV, or Nerve Conduction Velocity test. The NCV measures the speed of nerve conduction along the course of the nerve and is compared to known normals and the opposite elbow.

How is cubital tunnel syndrome treated?

Non-operative treatment

Initial treatment consists of avoiding provocative activities that precipitate symptoms. Anti-inflammatory medication and ice as necessary may be of value. Leaning on the elbow should be avoided. The use of an elbow pad or elbow splinting (usually only at night) may be recommended to prevent full bending of the elbow. Stretching and strengthening exercises of the muscles of the forearm and elbow are important. Referral to a physical therapist or an athletic trainer may be recommended for treatment.

Operative treatment

Failure of non-operative treatment may justify surgical intervention. Surgery involves decompression of the nerve by incising over the nerve’s sheath and releasing any adhesions or compression along the course of the nerve. If the nerve is “unstable”, it is usually transferred anteriorly (in front of) the medial epicondyle (inside elbow bone) and positioned either subcutaneously (under the skin) or sub-muscular (under the muscle).

What are the complications of treatment?

Possible complications of non-operative treatment include:

•  Persistent symptoms, impairment of athletic activity (such as in overhead athletes)

Possible complications of operative treatment include:

•  Numbness, tingling, persistent symptoms

When can you return to your sport/activity?

Return to activity is permitted as soon as symptoms have resolved. Activity modification may be necessary if the symptoms do not resolve with standard non-operative treatment. Return after surgical intervention may require three to four months depending upon whether the nerve required transposition (moving it anteriorly in front of the elbow) and the nature of the sport.

How can cubital tunnel syndrome be prevented?

•  Appropriately warm up and stretch before practice or competition

•  Maintain appropriate conditioning:

  •  Wrist, forearm and elbow flexibility

  •  Muscle strength and endurance

•  Wear proper protective equipment, including elbow pads

•  Use proper throwing techniques