Cartilage Injury in the Knee: Assessment and Treatment Options

Aaron J. Krych, MD; Daniel B. F. Saris, MD, PhD; Michael J. Stuart, MD; Brittney Hacken, MD

Disclosures

J Am Acad Orthop Surg. 2020;28(22):914-922. 

In This Article

Osteochondral Autograft Transplant/Mosaicplasty

Osteochondral autograft transfer is a treatment best reserved for small osteochondral lesions in the knee that are <2 cm2 in size. This treatment involves harvesting an osteochondral plug from a nonweight-bearing surface of the knee, typically the peripheral aspect of the medial or lateral trochlea or intercondylar notch and then transferring this to a weight-bearing chondral lesion. The plugs harvested are typically 6 to 10 mm in size, and numerous plugs can be used in a mosaic format if needed for larger defects (Figure 4). The plug itself offers a hyaline cartilage surface with underlying subchondral bone which assists in the healing process. If gaps are present, then fibrocartilage fills in the surrounding defects around the osteochondral autograft plug and native surrounding cartilage. The procedure has been described both with an open arthrotomy and arthroscopically. The grafts are typically press fit into the lesion, and no hardware is necessary if stable fixation is able to be achieved.[24] Because of donor site morbidity, this treatment is typically limited to lesions less than 2 cm2 in size. In our opinion, the ideal indication would be a transfer of one or two 8-mm osteochondral autograft plugs. Therefore, in addition to lesion size, the geometry must also be favorable with a narrow, linear lesion. We find that few lesions of this size are symptomatic, and therefore, there are limited indications for this technique.

Figure 4.

Photographs showing the osteochondral autograft transfer with two plugs: (A) the small contained cartilage lesion is seen. B, Two osteochondral autograft plus are fitted in to the defect in a snowman configuration.

Advantages include a single stage procedure, lower cost compared with an allograft, and the ability to treat lesions with subchondral bone involvement. Utilization of the patient's native cartilage and living bone should theoretically improve healing potential. Osteochondral autologous transplantation (OAT) results in improved subjective scores, higher rates of return to sport in athletes, 89% versus 51% in OAT compared with microfracture,[25] and lower failure rates at long-term follow-up when compared with microfracture.[9,25–27] At the 3-year follow-up, 86% of OAT patients had continuation of sport compared with just 27% of microfracture patients in an athletic cohort. These results further decreased at the 10-year follow-up, with 34% and 17% of the OAT and microfracture patients, respectively, continuing to participate in sporting activities.[25]

A limitation of this technique is that it can be difficult to contour match the donor cartilage to the lesion to create a congruent surface. In addition, larger lesions are more difficult to treat because they necessitate a mosaic construct, and there is concern for donor site morbidity.

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