Osteochondral autograft transfer. A, Size of defect determined. B, Harvester driver extractor assembled with tube harvester and collared pin loaded. C, Harvester driven into subchondral bone. D and E, Harvesting of graft. F, Calibrated osteochondral allograft transplantation system (OATS) alignment stick of appropriate diameter used to measure recipient socket depth and align angle of recipient socket correctly to position of insertion portal. G, Donor harvester, collared pin, and autograft core reinserted into driver. H, Donor tube harvester inserted into recipient socket. I, Sizer tamp, measuring 1 mm in diameter larger than bone core, positioned over bone core. J, Harvested and transferred cores. SEE TECHNIQUE 51.15.