The common flexor-pronator origin is primarily on the anterior aspect of the medial epicondyle.

The common flexor-pronator origin includes the humeral head of the pronator teres (PT), the flexor carpi radialis (FCR), the flexor carpi ulnaris (FCU), and a small portion of the flexor digitorum superficialis (FDS).

The palmaris longus also shares the origin, although this is not likely to be clinically relevant.

Epicondylitis results from repetitive microtrauma followed by an incomplete reparative response that results in tendinosis, a pathologic state in which the degenerative tendon cannot heal itself effectively.

Epicondylitis can be seen with medial collateral ligament instability whereby myotendinous overload occurs in an attempt to dynamically stabilize the ulnohumeral joint. In this scenario, ulnar neuropathy often is part of a trio of pathology.

The most common tendon insertions affected are the PT and FCR; however, any tendon insertion of the common flexorpronator origin can be involved.

Most patients improve with conservative treatment.

However, a greater percentage of patients with medial epicondylitis go on to surgical treatment when compared to patients with lateral epicondylitis.³

Patients commonly complain of forearm pain rather than elbow pain. At times, the inflammation is significant enough to cause irritation of the ulnar nerve as it enters the FCU, causing ulnar nerve symptoms (eg, local irritability and distal numbness and tingling).

Onset usually is insidious, but the patient may recall an inciting event.

Medial epicondylitis can be present simultaneously with lateral epicondylitis.

Examination methods include the following:

Resisted pronation is highly sensitive for medial epicondylitis.¹

A decreased range of motion (ROM) suggests intra-articular pathology such as arthritis.

If resisted wrist flexion reproduced symptoms, it supports a diagnosis of medial epicondylitis.

Tap the ulnar nerve in the cubital tunnel and along its path into the FCU. Presence of a tingling sensation locally prompts further nerve investigation.

Flex patient’s elbow maximally, then compress the ulnar nerve just proximal to the cubital tunnel. Presence of hand numbness or tingling prompts further nerve investigation.

Plain radiographs may show calcifications at the flexorpronator origin.

Magnetic resonance imaging (MRI) will reliably demonstrate increased intratendon signal on T2-weighted sequences. Most will also show increased intratendon signal and/or tendon thickening on T1-weighted sequences.

Electrophysiologic testing (electromyography and nerve conduction studies) are warranted if patients have ulnar nerve symptoms; but with mild ulnar neuropathy, these tests have a very low sensitivity.

Pronator syndrome

Medial collateral ligament injury

Ulnar neuropathy

Arthritis

Cervical radiculopathy

Malingering

Appropriate initial treatment includes avoidance of painful activities and symptomatic relief with nonsteroidal antiinflammatory drugs and ice.

Daytime wrist bracing for exertional activities

Physical or occupational therapy to supervise and instruct on stretching and strengthening protocol for patients not otherwise inclined to comply with those instructions

Although corticosteroid injection at the medial epicondyle has been shown to provide temporary symptomatic relief, it does not affect the natural history.⁵ Repeat injections should be avoided as they can lead to tendon weakening and rupture.

A minority of patients fail nonoperative management.

Careful patient selection will ensure an excellent outcome with surgical management.