Mapping Origins of Tendons on the Medial Epicondyle to Improve Treatment of Medial Epicondylitis: Anatomical Study.

Purpose: Medial epicondylitis is a tendinosis found commonly in throwing and golfing athletes. Although there are choices for nonsurgical treatments, when these fail, surgical intervention can be considered. When surgical treatment is performed, the objective is to debride the diseased tissue from the epicondyle. The purpose of this study was to clarify the locations and size of the common flexor tendons and medial collateral ligament (MCL) relative to each other and to the posterior ridge of the medial epicondyle.

Methods: The common flexor tendons and MCL were dissected and reflected their origin on the medial epicondyle in six cadaver elbows. Measurements were taken from the posterior and distal ridges of the medial epicondyle with respect to the humerus. Each origin was also measured for its height and width.

Results: The flexor carpi ulnaris origin starts at a mean of 4.2 mm from the posterior ridge of the medial epicondyle and extends anteriorly an average of 4.8 mm. The flexor carpi radialis starts at a mean of 4.2 mm from the posterior ridge and extends anteriorly an average of 7.4 mm. The pronator teres begins at a mean of 4.6 mm from the posterior ridge and extends an average of 5.7 mm anteriorly. The MCL starts at an average of 10.4 mm from the posterior ridge and extends 5.2 mm anteriorly.

Conclusions: The measurements found have allowed the creation of a map of the specific common flexor tendon origins and their sizes on the medial epicondyle, as well as their position relative to the MCL.

Clinical Relevance: A surgeon may debride 1 cm anteriorly from the posterior ridge of the medial epicondyle to safely address the affected tissues and ensure the safety and integrity of the MCL.