When Lateral Epicondylitis Is Not Lateral Epicondylitis: Analysis of the Risk Factors for the Misdiagnosis of Lateral Elbow Pain

Background: Lateral elbow pain, often attributed to lateral epicondylitis, presents diagnostic complexities. Lateral epicondylitis, or tennis elbow, is the most frequent cause of lateral elbow pain, but a differential diagnosis among all the potential causes of lateral elbow pain is not easy. Purpose: To evaluate the rate of misdiagnoses in patients previously diagnosed with lateral epicondylitis, identify at-risk patient profiles, and determine sensitive clinical tests for a misdiagnosis. Study Design: Case series; Level of evidence, 4. Methods: A prospective analysis was conducted on 189 consecutive patients with a previous diagnosis of lateral epicondylitis and failed nonoperative treatment. According to medical history and a physical examination, patients were preliminarily classified into the typical or atypical lateral epicondylitis group. Atypical epicondylitis was defined as one of the following: atypical lateral pain location, history of trauma, limited range of motion (ROM), elbow swelling, negative Cozen test finding, and physical examination findings suggesting a misdiagnosis. Patients in the atypical group were further investigated for a potential lateral epicondylitis misdiagnosis using magnetic resonance imaging, computed tomography, and/or analysis of intraoperative samples according to suspected underlying abnormalities. Univariate and logistic regression analyses were conducted to assess the risk of a misdiagnosis. A standardized diagnostic analysis was performed to evaluate the clinical tests used during the physical examination to identify misdiagnosed patients. Results: A misdiagnosis occurred in 21 of 189 (11%) patients. The most common misdiagnoses were posterolateral elbow instability in 6 patients; radial nerve compression and inflammatory osteoarthritis in 3 patients each; and osteochondritis dissecans, posterolateral plica, and primary osteoarthritis in 2 patients each. The variables associated with a misdiagnosis were young age (≤30 years; odds ratio [OR], 66.90; P < .001), history of trauma (OR, 17.85; P = .0027), history of a limitation of ROM and/or mechanical symptoms (OR, 16.68; P = .0278), history of elbow swelling (OR, 14.32; P = .0032), and number of corticosteroid injections (OR, 2.00; P = .0007). Atypical lateral pain location highly predicted a misdiagnosis, with a sensitivity of 90.5%. Conclusion: A misdiagnosis can occur in patients affected by longstanding lateral elbow pain. Young patients and patients with a history of elbow trauma, a limitation of ROM, swelling, corticosteroid injections, and atypical lateral pain should be highly suspected for a misdiagnosis.