Ulnar Nerve Subluxation in the Overhead Athlete: Predicted Loss of Force Following Submuscular Versus Modified...

Cubital tunnel syndrome and ulnar nerve subluxation are common issues for the overhead athlete and can be a considerable hindrance to their athletic performance. With the care of elite athletes in mind, there must be a balance between the relief of symptoms and preservation of capabilities. We quantified compromise of the flexor-pronator mass following modified subcutaneous versus submuscular ulnar nerve transposition.

Eight cadaveric upper-extremity specimens were studied to determine the amount of muscle compromise following modified subcutaneous and submuscular ulnar nerve transposition. The muscles of the flexor-pronator mass were then identified, including the flexor carpi ulnaris, flexor digitorum superficialis, flexor carpi radialis, and pronator teres. The muscles of the flexor-pronator mass were dissected along their length, and a line was marked where the ulnar nerve would cross the muscle during transposition. Each muscle of the flexor-pronator mass was excised from the forearm. The volume of each muscle was estimated by the technique of volume displacement using a graduated cylinder.

There was a significant difference in the loss of muscle volume between the two techniques. This translates to the potential loss of force from the flexor-pronator mass. Submuscular transpositions resulted in 4.67× more muscle volume loss than the modified subcutaneous approach.

When the ulnar nerve needs to be transposed, subcutaneous or modified subcutaneous ulnar nerve transposition results in less damage to the flexor-pronator mass.

These findings aid in surgical decision making in the overhead athlete in order to preserve muscle volume and force of the flexor-pronator mass.