Abstract
Background: Lateral elbow tendinopathy is a common condition that significantly alters the function of the upper extremities. In case of first-line treatment failure, different local injections are usually used. Due to the lack of sufficient evidence to support it, we conducted the study to compare the outcomes of different single injections, including Platelet-Rich Plasma (PRP), Corticosteroids (CS), Hyaluronic Acid (HA), and placebo (saline). Methods: Sixty patients with confirmed lateral elbow tendinopathy were enrolled in the study and divided into four groups. Pain intensity (average for the current day, at rest, during provocative tests) measured by Visual Analogue Scale (VAS), pressure pain threshold (PPT), Patient-Rated Tennis Elbow Evaluation (PRTEE), Disability of Arm, Shoulder and Hand (DASH), Subjected Elbow Value (SEV), and strength of selected muscle groups were measured before and during follow-up visits (1, 4, 12, 24, and 52 weeks after treatment). The treatment was considered successful when minimal clinically important difference (MCID) was achieved in primary outcomes (VAS, PRTEE). Results: A significant improvement was achieved in most measurements in all groups. At the final follow-up, MCID for the mean pain reduction measured with VAS and improvement in the PRTEE score were achieved in 52 and 54 patients, respectively. The complete absence of pain was achieved after 1, 4, 12, 24, and 52 weeks in 2, 5, 10, 22, and 40 patients, respectively. The comparison between the groups found a significant difference in pain intensity between CS and other groups one week after injection, between the CS and PRP group in the fourth week, and between PRP and HA in the fourth week (p < 0.05). No other significant differences were found between each group at each follow-up time point. Conclusions: We conclude that each injection treatment provides good long-term clinical outcomes, but not better than placebo. A CS injection might be regarded as a more effective treatment only within the first month post-injection.