Acute patellar dislocation is a painful, terrifying experience that always occurs suddenly. The recurrence is unfortunately common and each experience is just as painful to the patient. With each acute dislocation, additional intraarticular derangement occurs. Therefore the goals of treatments are not only to relieve acute pain by prompt reduction of the dislocation but also to remove any chondral or osteochondral fragments that may be present within the knee joint and to restore normal patellofemoral anatomy, thereby preventing recurrent dislocation and avoiding future patellar subluxation. To present the details of arthroscopic medial retinacular repair in acute patellar dislocation. we report 2 patients with treatment of acute patellar dislocation with osteochondral loose body.