Osteochondral allograft transplantation in the knee is an alternative to joint replacement that may be used to treat a young and healthy population with symptomatic cartilage defects. The defect may be identified by MRI and/or arthroscopy. When conservative management has failed, a diagnostic arthroscopy is indicated to asses the location, size, and severity of the defect(s). These findings determine what method is best suited for cartilage restoration. Osteochondral allograft transplantation is indicated for large lesions that have affected the cartilage and subchondral (beneath cartilage) bone. Osteochondral allografts are composed of fresh donor tissue and are procured from tissue banks that follow strict safety guidelines. This article will take you through a case study demonstrating an arthroscopic evaluation, cartilage transplant, and a sample phase 1 protocol for this procedure!