INTRODUCTION

Medial epicondylitis is the most common cause of medial elbow pain but is only 15% to 20% as common as lateral epicondylitis. The relative infrequency of medial epicondylitis has resulted in a paucity of information on medial epicondylitis, but work by Vangsness and Jobe,²⁸ Gabel and Morrey,⁵ Ollivierre and associates,¹⁸ and Kurvers and Verhaar¹¹ has clarified the pathology, treatment, and outcomes in medial epicondylitis. The significance of associated ulnar neuropathy at the elbow has also been assessed and is the primary component of the classification of medial epicondylitis. The results of nonoperative management, including corticosteroid injections, have been reported by Stahl and Kaufman.²⁵ The compilation of information in these studies⁶ has resulted in a clearer understanding of medial epicondylitis and its management, allowing more appropriate patient care.

ANATOMY

The anatomy of medial epicondylitis involves musculotendinous, neural, and ligamentous concerns. The flexor pronator origin at the anterior medial epicondyle is the central focus of medial epicondylitis. The pronator teres muscle originates in part off the superoanterior medial epicondyle, but its primary origin is from an intramuscular tendon (the medial conjoint tendon [MCT]) that has been previously described as the accessory anterior oblique ligament (AOL) or anisometropic AOL. Although it has been demonstrated to be a weak valgus stabilizer in near full extension, it is expendable and plays no role in static valgus stability in the presence of an intact AOL. The only clinical circumstance in which this structure plays a role in valgus stability is in elbow dislocations, in which if the flexor pronator mass is minimally disrupted, the MCT may prevent gross instability. The MCT is also the principle active valgus stabilizer, which may be a concern in athletic valgus loads especially throwing athletes.

The pronator teres origin off the MCT occupies the proximoradial side of this vertically oriented septum (Fig. 45-1). The flexor carpi radialis, which also has a very small direct muscular epicondylar origin, finds its primary origin off the distoulnar aspect of the MCT. Although additional muscular or tendinous origins off the epicondyle are seen, the critical lesion of medial epicondylitis consists of this MCT and its associated pronator teres and flexor carpi radialis origins. This septum bifurcates 2 to 3 cm distal to the epicondyle (Fig. 45-2) with the pronator teres radially, the flexor carpi radialis between the septa and the digital flexors ulnarly.

FIGURE 45-1 Illustration of medial conjoint tendon (MCT). Forceps are on the vertically oriented MCT. Note that the anterior oblique ligament (AOL) lies on the posterior margin of the MCT. Elevation of the MCT should be performed carefully to avoid injury to the AOL.

FIGURE 45-2 Intraoperative photograph of the two septae of the medial conjoint tendon, 2 cm distal to the epicondyle. Note the muscular attachments have been elevated. The radial septum (B) is bordered by the pronator teres muscle laterally, the flexor carpi radialis muscle resides between the septae, and the digital flexor muscle bellies are medial to the ulnar septum (A).

Although it plays a central mechanical role in medial epicondylitis, the MCT serves surgically as a landmark for the pathology of medial epicondylitis as well as a means of identification and avoidance of the AOL proper. The MCT rises off the anterior inferior epicondyle with an oblique parasagittal orientation extending approximately 12 cm into the proximal forearm. Immediately posterior to the proximal 3 to 4 cm of the MCT is the AOL (see Fig. 45-1). There is a surgical interval between the MCT and AOL, but anatomically, they are contiguous over the proximal 50% to 75% of the AOL. The distal 25% to 50% of the AOL is separate from the MCT’s posterior margin, an interval that allows for independent surgical manipulation of MCT and AOL distally. Any surgical elevation of the MCT off the medial epicondyle, posterior to the MCT, by definition, violates the origin of the AOL.

The neural concerns in medial epicondylitis consist of the medial antebrachial cutaneous nerve (MABCN) and the ulnar nerve. The MABCN courses in the subcutaneous tissue in the anteromedial arm¹³ until just proximal to the medial epicondyle, where it divides into an anterior branch, which travels distally, and a posterior branch,² which travels directly over the flexor pronator mass to the posterior medial forearm. The ulnar nerve rests on the posterior aspect of the medial intermuscular septum in the arm. As it approaches the medial epicondyle, it is covered by a retinaculum,¹⁵ which maintains its position preventing subluxation. It enters the forearm through the two heads of the flexor carpi ulnaris at the cubital tunnel. At entry into the cubital tunnel, the ulnar nerve lies immediately adjacent to the posterior margin of the flexor pronator mass.

PRESENTATION

Medial epicondylitis presents with medial elbow pain, which is related to activity, especially repetitive or forceful pronation. It has a peak incidence in the third through fifth decade, with a 2:1 male-to-female ratio. It occurs in the dominant elbow in 60% of cases and is associated with an acute injury (direct or indirect) in 30%, whereas 70% of cases have a more insidious onset. Associated ulnar neuropathy is seen in approximately 50% of cases, whereas associated diagnoses at a separate level (lateral epicondylitis, 30%; carpal tunnel syndrome, 25%; rotator cuff pathology, 20%) are also frequently seen on past medical history. A vocational contribution to the patient’s symptoms may be seen in more than 50% of cases; an avocational contribution is seen in 10% to 20% of patients (hence, the eponym golfer’s elbow). The prevalence of medial epicondylitis is approximately one half of 1%, with smoking, obesity, repetitive, and forceful activities being significant risk factors.²⁰

Physical examination demonstrates direct tenderness over the anterior aspect of the medial epicondyle in essentially all cases. Some patients may have maximum tenderness just distal to the epicondyle in the proximal flexor pronator mass. Resisted pronation tenderness is seen in 90% and resisted wrist palmar flexion tenderness in 70% of patients. Range of motion is typically normal. Associated medial collateral ligament insufficiency may be tested with valgus stress testing, as described by Jobe and associates⁹ (valgus stress at 30 degrees of flexion with palpation of the AOL) or the moving valgus stress test, as described by O’Driscoll and associates.¹⁷ The ulnar nerve should be evaluated, including testing for the presence of Tinel’s sign, elbow flexion test, nerve compression test, and ulnar nerve subluxation. Distal objective function (two-point discrimination, intrinsic strength, and dorsal cutaneous nerve status) completes the ulnar nerve examination. The classification of medial epicondylitis⁵ is based on the presence and severity of concomitant ulnar neuropathy at the elbow. Type I medial epicondylitis includes those patients with no associated ulnar nerve symptoms. Type II medial epicondylitis is divided based on the degree of ulnar nerve involvement. Type IIA has ulnar nerve symptoms with no objective deficit, whereas type IIB has objective deficits on physical exam or electromyography.

EVALUATION

Radiographic evaluation should include plain radiographs to rule out associated lesions (e.g., osteoarthritis) as well as valgus stress radiographs²³ if medial instability is suspected (Fig. 45-3). Medial epicondylar calcification is seen in 10% to 20% of cases but is not prognostic. Magnetic resonance imaging (MRI) has concentrated on lateral epicondylitis,^12,19 but within these series and medial epicondylitis–specific series,¹⁰ it has a high sensitivity and specificity. Because medial epicondylitis is primarily a clinical diagnosis, MRI should be reserved for more complex situations such as reoperation or associated medial collateral ligament concerns.

FIGURE 45-3 Valgus stress radiograph for assessment of valgus instability as a cause of medial elbow pain.

(From Woods, G. W., and Tullos, H. S.: Elbow instability and medial epicondyle fractures. Am. J. Sports Med. 5:23, 1977.)

Electrodiagnostic evaluation of the ulnar nerve is indicated in cases of concomitant ulnar neuropathy. Although electromyographic changes are rare except in type IIB cases, nerve conduction slowing either absolutely (less than 50 m per second) or relative (to proximal or distal segments) is usually seen in type IIA cases.

The differential diagnosis of medial elbow pain includes proximal neurogenic sources (cervical radiculopathy, thoracic outlet syndrome) as well as shoulder-level musculoskeletal sources, each of which can be excluded with appropriate evaluation. Local causes of medial elbow discomfort are limited but should be evaluated as well. A snapping medial head of the triceps²⁴