Ultrasound Guided Injection of Collagen for Elbow Lateral Epicondylitis - A Pilot Study.

BACKGROUND: Lateral epicondylitis (LE), commonly known as tennis elbow, is an enthesopathy involving the insertion of the common extensor tendon (CET), frequently associated with overuse and degenerative changes. While several conservative therapies exist-including NSAIDs, corticosteroids, PRP, and physiotherapy-none have proven uniformly effective, and some carry undesirable side effects. Recently, collagen peptides have emerged as a promising therapeutic option due to their regenerative and anti-inflammatory properties. OBJECTIVE: To evaluate the efficacy and safety of ultrasound-guided injections of low-molecular-weight peptides (LWPs) derived from hydrolyzed collagen in patients with LE and partial-thickness CET tears. METHODS: This retrospective study included 13 patients with persistent epicondylar pain and ultrasonographic evidence of partial CET tears. Patients received two US-guided injections of collagen peptides, at baseline and at two weeks. Clinical outcomes were assessed using the Numeric Rating Scale (NRS) for pain, while structural changes were monitored via greyscale (GS) and Power Doppler ultrasound at predefined follow-up points. RESULTS: Pain scores improved significantly as early as three days post-injection (mean NRS reduction from 7.5 to 4.8; p<0.05), with continued improvement to 2.5 at one month. Doppler signal decreased significantly, indicating reduced inflammation. Tendon lesions resolved in 8/13 patients and decreased in size in 3. Only two patients experienced mild, transient post-injection pain. CONCLUSION: Collagen peptide injections appear to be safe and effective treatment for LE, offering significant pain relief and tendon healing. These preliminary findings support further prospective, controlled trials to validate long-term efficacy and positioning in clinical practice.