Purpose: To evaluate the clinical and ultrasonographic changes in the morphology and vascularity of the common extensor tendon after injecting platelet-rich plasma (PRP) or corticosteroid (CS) for recalcitrant lateral epicondylitis (LE).
Methods: 30 patients aged 18 to 60 years with recalcitrant (>6 months) LE not responsive to oral medication or non-invasive treatment were randomised to receive PRP (n=15) or CS (n=15) injection. Patients were assessed using the visual analogue scale (VAS) for pain, Disabilities of the Arm, Shoulder and Hand Scale (DASH) score, Oxford Elbow Score, modified Mayo Clinic performance index for the elbow (modified Mayo score), and hand grip strength. Ultrasonography was performed by a musculoskeletal ultrasonologist to evaluate for tear at the common extensor origin, oedema at the common extensor origin, cortical erosion, probe-induced tenderness, and thickness of the tendon.
Results: The VAS for pain, DASH score, Oxford Elbow Score, modified Mayo score, and hand grip strength all improved significantly from pre-injection to the 6-month follow-up in the PRP and CS groups. However, in the CS group, the scores generally peaked at 3 months and then deteriorated slightly at 6 months indicating recurrence of symptoms, which involved 46.7% of the CS patients. At 6 months, the number of patients positive for various ulrasonographic findings generally decreased. However, in the CS group, the number of patients with reduced thickness of the common extensor tendon increased from 2 to 12, and the number of patients with cortical erosion at the lateral epicondyle increased from 9 to 11.
Conclusion: PRP appeared to enable biological healing of the lesion, whereas CS appeared to provide short-term, symptomatic relief but resulted in tendon degeneration.