Table 2.

Technical Pearls and Pitfalls

Pearls	Pitfalls
Verify accurate preoperative measurement of the cartilage lesion to ensure that a full hemicondylar allograft is not necessary. If necessary, consider a diagnostic arthroscopy prior to OCA transplantation or having more than 1 graft available.	Ensure that the OATS harvester is perpendicular to the graft prior to impaction, as deviation may cause an abnormal fit at the articular surface.
Have a 15-mm OCA core available at the time of surgery, as it is always possible to downsize the graft to a smaller size.	Excessive manual impaction of the graft into the recipient socket can result in chondrocyte death.
Use the arthroscope to accurately measure the depth of the socket at desired locations.	Excessive reaming of the underlying bone necessitates a larger graft length. The amount of subchondral bone should be minimized to reduce an immune reaction.
Soak the OCA core in bone marrow aspirate concentrate prior to implantation, as this may aid in graft healing and biologic incorporation.

OATS, Osteochondral Autograft Transfer System; OCA, osteochondral allograft.