To compare ultrasound and shear wave elastography (SWE) changes in the common extensor tendon over time after platelet-rich plasma (PRP) or corticosteroid (CS) treatment, and to assess for correlations between patient-reported outcomes (PROs) and US/SWE changes of the common extensor tendon.

A secondary analysis of a prospective double-blinded, randomized controlled trial comparing US and SWE changes after a single treatment of PRP or CS for the treatment of lateral epicondylosis was conducted. Subjects 18–65 years with recalcitrant lateral elbow pain were enrolled between 3/1/2017 and 4/1/2019 and randomized to a treatment group. US/SWE of the common extensor tendon was performed at baseline, 26 weeks, and 52 weeks, and PROs were also recorded. Treatment effects between groups were compared using linear mixed effects models.

Fifty elbows in 47 subjects (mean 48 years ± 8; 25 women) were randomized to two groups–PRP (N = 26) and CS (N = 24). Shear wave speed (SWS) increased with PRP more than with CS at both 26 weeks (2.02 m/s ± 0.61; p = 0.002) and 52 weeks (2.98 m/s ± 0.49; p < 0.01). At 26 weeks, no differences were detected between treatments by conventional US. At 52 weeks, echogenicity and hyperemia improved with PRP relative to CS (p < 0.05). Increased SWS correlated with improvement in all PROs (p < 0.05). For conventional US changes, the only correlation to PROs was that of echogenicity with pain (p = 0.04).

SWS increased more with PRP than CS at 26- and 52-week post-treatment for lateral epicondylosis, and increased SWS correlated with clinical improvement.

Question Can SWE detect healing changes in the common extensor tendon associated with clinical improvement of lateral epicondylitis in patients treated with PRP or CS injection?

Findings Higher common extensor tendon SWSs were associated with clinical improvement and improved more in those treated with PRP than with CS.

Clinical relevance statement SWE may be able to quantitatively detect treatment changes in tendons associated with clinical improvement.