Abstract
RATIONALE: Lateral epicondylitis, commonly known as tennis elbow, is a chronic condition characterized by tendinosis at the insertion site of the lateral epicondyle. Various treatment methods are available, ranging from conservative to surgical options for refractory lateral epicondylitis. Recently, platelet-rich plasma (PRP) injections have shown effectiveness for treating this condition. This study aimed to evaluate the effectiveness of injecting a mixture of allodermal matrix (ADM) and leukocyte-rich PRP (LRPRP) for tendon regeneration. PATIENT CONCERNS: A 59-year-old man and a 62-year-old man, both with full-thickness tears in the common extensor tendon, presented persistent elbow pain despite undergoing several conservative treatments, including steroid injections, extracorporeal shock wave therapy, physical therapy, and medication previously. DIAGNOSES: The patients were diagnosed with refractory lateral epicondylitis using ultrasonography and magnetic resonance imaging (MRI). INTERVENTIONS: We performed injections of a mixture of ADM and LRPRP into the full-thickness tear of the common extensor tendon. OUTCOMES: One year after the procedure, visual analogue scale pain scores, patient-rated tennis elbow evaluation scores, quick disabilities of the arm, shoulder, and hand scores, and Nirschl scores had all improved significantly from baseline. In case 1, MRI scans obtained at 6 and 12 months postinjection demonstrated improved tendon integrity in full-thickness tear of the common extensor tendon. In case 2, similar improvements were observed on the 6-month postinjection MRI. LESSONS: Injection of a mixture of ADM and LRPRP at the site of full-thickness tears in the common extensor tendon of the elbow can enhance tendon integrity. This treatment also improves functional status in cases of recalcitrant lateral epicondylitis.