• Osteochondral allograft is our preferred method of treatment for medium- to large-sized articular cartilage defects (>15 mm diameter) in the femur.

• Microfracture

▪ Limited durability

• Osteochondral autograft transplantation

▪ Risk of donor-site morbidity¹

• Autologous chondrocyte implantation²,³

▪ Limits to graft size

▪ Need for secondary surgery

▪ Prolonged recovery

• Allograft tissue is harvested within 24 hours of donor death.

• Chondrocyte viability and extracellular matrix integrity directly affect postoperative outcomes, and their preservation is critical.

• The recommended maximal storage time is 28 days, which, when appropriately preserved, correlates with 70% chondrocyte viability.⁴

• Storage in serum-free culture medium improves chondrocyte viability and metabolism compared to lactated Ringer solution.⁵

• More recently, we augment osteochondral allografts with bone marrow aspirate concentrate (BMAC) harvested from the iliac crest at the time of surgery.

• Concomitant opening wedge high tibial osteotomy and opening wedge distal femoral osteotomy are done for associated varus and valgus deformity, respectively.

• Defect sizing can be done with preoperative MRI scans or staged diagnostic arthroscopy to obtain the appropriately sized allograft tissue (Figs. 59-1 and 59-2).

• The patient is positioned supine on a standard operating table.

• A tourniquet is placed on the proximal thigh.

• A lateral post is positioned along the proximal thigh, at the level of the tourniquet, and confirmed to allow application of a valgus-directed force for arthroscopy of the medial compartment.

• After the patient is sedated, BMAC is harvested from the ipsilateral iliac crest.

• Standard diagnostic arthroscopy is performed to inspect and size the lesion to confirm optimal treatment strategy (Fig. 59-3). Any concurrent meniscal pathology is treated.

• Typically, a fresh femoral hemicondyle is used for femoral condylar lesions, while a distal femoral specimen is preferred for trochlear lesions. The graft is opened and soaked in antibiotic saline.