Sixty-one patients with chronic lateral epicondylitis and MRI-confirmed common extensor tendon tears in the elbow were randomized to receive either leukocyte-rich platelet-rich plasma injections (LRPRP) (n=31) or a combination of leukocyte-rich platelet-rich plasma and allodermal matrix injections (LRPRP plus ADM) (n=30). The outcomes of interest were tendon integrity assessed by MRI, pain and functional measures using the visual analog scale (VAS), Quick Disabilities of the Arm, Shoulder, and Hand (DASH), Patient-Rated Tennis Elbow Evaluation (PRTEE), and the Nirschl score. Outcomes were assessed over more than twelve months, with MRI evaluation at six months. Overall, the results of the study revealed that both groups experienced significant improvements in pain and functional scores (P < 0.001), with no significant clinical differences between treatments. However, imaging demonstrated a significantly greater improvement in tendon integrity in the LRPRP plus ADM group compared with LRPRP alone (P = 0.020). These findings suggest that combining ADM with LRPRP enhances structural tendon integrity despite similar clinical outcomes.