Association of steroid injection with soft-tissue calcification in lateral epicondylitis

Steroid injections are among the most commonly used conservative treatments for lateral epicondylitis (LE). Although soft-tissue calcification has been reported as a steroid injection complication in certain tendons, such an association in LE has not been established. This study's purpose was to determine any association of both a history of steroid injection and the number of steroid injections with the types of calcification found in LE.

This study included 110 patients (110 elbows) with LE diagnosed from February 2016 to October 2017. We categorized calcifications seen on standard elbow radiographs as soft-tissue calcifications or enthesophytes using the classification of Shillito et al. Using logistic regression analyses, we calculated odds ratios (ORs) and 95% confidence intervals (CIs) for various factors possibly affecting calcification in LE: age, sex, body mass index, dominant-side involvement, occupation, symptom duration, hand-grip power, pain score on a visual analog scale, and treatment methods. The evaluated treatments included stretching exercise, extracorporeal shockwave therapy, and steroid injections.

In the univariate analysis, the visual analog scale pain score, a history of steroid injection, and the number of steroid injections were significantly associated with soft-tissue calcification (P ≤ .020). In the multivariable analysis, a history of steroid injection (OR, 7.63; 95% CI, 1.63-35.72) and the number of steroid injections (OR, 1.18; 95% CI, 1.06-1.32) were significantly associated with soft-tissue calcification (P ≤ .010).

The significant association of steroid injections with soft-tissue calcification in LE suggests that this calcification is likely to be an iatrogenic complication of steroid injection.