Magnetic resonance imaging predicts outcomes of conservative treatment in patients with lateral epicondylitis.

BACKGROUND: The clinical validity of positive magnetic resonance imaging findings in lateral epicondylitis is controversial. We hypothesized that magnetic resonance imaging could predict the outcome of conservative treatment. This study determined the relationship between magnetic resonance imaging-defined disease severity and treatment outcomes in patients with lateral epicondylitis.

METHODS: This retrospective single-cohort study included 43 conservatively managed and 50 surgically treated patients with lateral epicondylitis. The magnetic resonance imaging scores and clinical outcomes were examined six months post-treatment, and the former was compared between patients with good and poor treatment outcomes. We developed operating characteristic curves of magnetic resonance imaging scores for treatment outcomes, and divided patients into magnetic resonance imaging-mild and severe groups according to the obtained cut-off value of the scores. We compared the outcomes of conservative treatment with that of surgery for each magnetic resonance imaging severity.

RESULTS: Twenty-nine (67.4%) conservatively treated patients had good outcomes, while 14 (32.6%) had poor outcomes. The magnetic resonance imaging score was higher in patients with poor outcomes; the cut-off value was 6. Forty-three (86.0%) surgically treated patients had good outcomes, while 7 (14.0%) had poor outcomes. There was no significant difference in magnetic resonance imaging scores between patients with good and poor surgical outcomes. In the magnetic resonance imaging-mild group (score ≤ 5), the outcome showed no significant difference between the conservative and surgical treatment groups. In the magnetic resonance imaging-severe group (score≥6), the outcome of conservative treatment was significantly worse than that of surgical treatment.

CONCLUSIONS: The magnetic resonance imaging score was associated with conservative treatment outcomes. A treatment strategy that includes surgery should be considered for patients with severe magnetic resonance imaging findings; this is not recommended for those with mild magnetic resonance imaging findings. Magnetic resonance imaging is helpful in determining the best treatment strategies for patients with lateral epicondylitis.

LEVEL OF EVIDENCE: III, Retrospective cohort study.