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from the Pro Physical Therapy Staff

Lateral Epicondylitis versus Posterolateral Rotatory Instability

Lateral elbow pain is one of the most common complaints of pain of the upper extremity in the adult population that can be debilitating; often times affecting ADLs, recreational and vocational activities. Although lateral epicondylitis has such a high occurrence, one must be acutely aware of less common differential diagnoses.

Lateral epicondylitis, more commonly called tennis elbow, is an inflammation and degeneration of the wrist extensor muscles at its origin at the lateral epicondyle. Tennis elbow often affects people over the age of 40 and is more likely to affect their dominant side. Patients often complain of lateral elbow pain reproduced with activities such as lifting, gripping and simple functional tasks such as shaking hands or opening jars. In the acute stages it is an inflammatory process, however, in chronic cases it is classified as a degeneration of the extensor tendon, mostly of the extensor carpi radialis brevis. Tennis elbow is usually a result of cumulative trauma to the affected tendon causing micro tears which contributes to the chronic pain cycle. Although in most cases tennis elbow is a repetitive strain injury sometimes it could be from direct trauma to the lateral aspect of the elbow resulting in symptoms of lateral epicondylitis.

Despite the various sources of lateral elbow pain, often times nontraumatic or chronic elbow pain is quickly labeled tennis elbow because of the frequency of lateral epicondylitis in the outpatient orthopedic setting. During examination, one should pay careful attention to history and symptoms that correlate with common impairments but also keep an eye out for less common disorders. Some differential diagnoses include radial tunnel syndrome, C5, C6 nerve root compression, bursitis, arthritis and posterolateral rotatory instability, the latter of which most closely mimics lateral epicondylitis.

Posterolateral rotatory instability (PLRI) should be considered in the cases of persistent or recurrent symptoms of tennis elbow. Lateral stability of the elbow depends on the integrity of the lateral collateral ligament and secondary soft-tissue restrains. Posterolateral rotatory instability of the elbow can occur with elbow trauma, congenital cubitus varus deformity and injury to the lateral collateral ligament (LCL) during surgical procedures for lateral epicondylitis. In cases of trauma, the LCL can be injured by a fall on the outstretched hand involving a combination of axial compression external rotation, and valgus forces in which the body rotates internally on a supinated forearm.  (1)

In cases of PLRI without any obvious signs of instability or red flag symptoms of other disorders, patients will initially present with symptoms similar to lateral epicondylitis.  Patients will complain of point tenderness at the lateral epicondyle and pain with resisted wrist and middle finger extension.  However, long term, these symptoms become chronic and unchanging despite traditional treatments of steroid injections, splinting, counterforce bracing, activity modification, and therapy. 

There are clinical tests available to differentiate lateral epicondylitis from posterolateral rotatory instability including the lateral stress test and the pivot shift test. Along with clinical provocative maneuvers, other helpful diagnostic tools include the MRI. In a study done by Kalainov DM, and Cohen MSM, three patients with symptomatic, chronic, unresolving tennis elbow underwent X-rays and MRIs. The X-rays were unremarkable in all three cases, however, the MRI revealed further pathology. In 2 patients the findings were positive for rupture of the LCL, retraction of the common extensor tendon, and synovial fistula and effusion.

Nonoperative treatment for PLRI may include, but is not limited to, immobilizing the forearm in pronation while allowing elbow flexion and extension in a hinge brace to protect the ligaments.  Operatively, treatment may include debridement and reconstruction of the extensor tendon origin and the LCL.  Operative and nonoperative treatment differs depending upon the extent of damage to the stabilizing structures and according to the treating physician.

Lateral elbow pain remains a highly frequent complaint in the adult population which is often times difficult to treat.  Despite its frequency, it is important to explore differential diagnoses, especially in the more chronic cases, to ensure the most appropriate and successful plan of care.


(1)  Marilyn Lee, OTR/L, CHT  “Posterolateral Rotatory Instability of the Elbow in Association with Lateral Epicondylitis: A Report of Three Cases [Case Reports] Kalainov DM, Cohen MSM. J. Bone Joint Surg. May 2005;87-A(5):1120-5
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