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 Allograft Transplant

OCAs have shown to be successful for a variety of cartilage lesions. In particular, these grafts are useful in young healthy patients with large and deeper osteochondral lesions >2 cm2 in size. These grafts may also be used for those with less-contained cartilage defects, for those with involvement of the underlying subchondral bone, and offer an elegant solution in revision settings. OCAs are not ideal for obese patients or those who use tobacco or corticosteroids because research has shown higher failure rates in these patients, as well as those with inflammatory arthritis.[28,29]

Historically, fresh OCAs were implanted within 24 to 48 hours; but, with more rigorous regulations now in place, these grafts are not typically implanted until a minimum of 14 days postharvest to allow for final aerobic cultures to be negative. Graft chondrocyte viability has been shown to be directly proportional to time since harvest; so, once the graft is released to the surgeon, the surgery is typically scheduled within 1 to 2 weeks.[30] OCAs have viable cartilage but require creeping substitution for bone integration with the host bone and therefore require a period of nonweight bearing or toe-touch weight-bearing after surgery if on a weight-bearing surface to allow for healing.[29]

Surgical technique involves debriding the cartilage lesion and subchondral bone to a stable healthy rim. OCA-specific instrumentation can then be used for the recipient and donor site to create a press-fit fixation of the allograft (Figure 5). Contouring of uncontained lesions must be performed by the surgeon to allow for appropriate size and depth of the graft. These uncontained lesions may require compression screw fixation to stabilize the graft.

Figure 5.

Photographs of the osteochondral allograft (OCA) transfer (A) shows a lesion that has been cut and reamed with a clean rim of healthy cartilage and bleeding subchondral bone. B, Shows an OCA that has been press fit to the native femoral condyle. The small mark on the cartilage is used to denote orientation of the graft from the allograft donor to the recipient site.

OCAs have shown promising outcomes in past studies when used for the correct patient cohort and when concurrent pathology is also corrected. Generally, studies report approximately 82% success rate after the surgery with most failures occurring on average approximately 42 months after surgery.[29,31] More complex lesions that require multiple grafts in a snowman configuration have higher failure and revision surgery rates as compared to a single graft, but overall, patients experience notable clinical improvement.[32] OCAs also provide mature hyaline cartilage that is an immediate functional surface for rehabilitation and loading, unlike cell-based options that require maturation over time. Limitations include limited availability, waiting time, and the high cost of a fresh OCA. Recent efforts have been made to release the grafts available as soon as testing is completed.

Fresh OCA precut plugs up to 16 mm in diameter are also now available. These plugs are limited by their shelf life but do provide an option for osteochondral lesions that are considered too large for osteochondral autograft because of potential donor site morbidity. Further research is needed to determine the long-term outcomes of these grafts.[33]

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