Intratendinous Injection of Autologous Conditioned Serum for Treatment of Lateral Epicondylitis of the Elbow: A Pilot Study

Background: Autologous conditioned serum (ACS) has been effectively used in treatment of osteoarthritis. However, less is known about its efficacy in tendon disorders. In this pilot study, we aimed to evaluate the short- and long-term effects of intratendinous injection of ACS in lateral epicondylitis (LE) of the elbow. Methods: This prospective cohort included 42 patients with LE of the elbow who received 4 intratendinous injections of Orthokine (R) (Orthogen Lab Services GmbH, Dusseldorf, Germany) under local anesthesia over 2 weeks in an outpatient setting. The clinical and functional outcomes of injections were evaluated at 3 months and 1 year after the procedure. Pain was assessed using a visual analog scale (VAS) and functional assessment was made using the Mayo Elbow Performance Score (MEPS) and Oxford Elbow Score (OES). Results: The pre-injection VAS score (7.07 +/- 1.19) improved significantly after the procedure at both 3 months (3.55 +/- 0.56, P < 0.001) and 1 year (1.73 +/- 0.82, P < 0.001). Similarly, the mean MEPSs were significantly different between baseline and 3 months (56.42 +/- 7.51 vs. 79.76 +/- 3.81, P < 0.001) and between baseline and 1 year (56.42 +/- 7.51 vs. 94.28 +/- 4.06, P < 0.001). The baseline OESs (84.17 +/- 6.07) also improved with intratendinous injection of ACS at 3 months (41.96 +/- 9.23, P < 0.001) and 1 year (7.43 +/- 4.31, P < 0.001). Only six patients (14.2%) had mild ecchymosis and swelling around the injection site which resolved spontaneously. Conclusion: ACS is a promising option for treatment of LE of the elbow, given its early onset of pain-relieving action and long-lasting functional effects. These findings await confirmation by large-scale and prospective trials.