A comparison of open versus arthroscopic harvesting of osteochondral autografts

Osteochondral autograft transfer is a technique for treatment of traumatic and degenerative cartilage lesions. A graft in which the cartilage cap is oriented perpendicular to the long axis of the graft is ideal because it can both restore the cartilage tidemark and minimize articular step-off at the recipient site. This study determines if osteochondral harvest technique (arthroscopic versus mini-open) or donor site location affects suitable graft harvest. One hundred and twenty eight osteochondral grafts were harvested in 16 cadaver knees utilizing a 7 mm OATS chisel from four donor sites: lateral supracondylar ridge, lateral femoral condyle, lateral intercondylar notch and medial femoral condyle. Mini-open and arthroscopic harvesting techniques were equally employed. Radiographic methods were used to analyze graft perpendicularity. Statistical analysis comparing graft suitability based on technique and donor site location was performed. There were no statistically significant differences (p > 0.05) in graft suitability regardless of the technique used or donor site location. 69% of arthroscopic and 56% of mini-open graft harvest were considered suitable, possessing a cartilage cap and graft axis angle that would create less than 1 mm of articular incongruity. Incongruity results when the angle between the subchondral bone plug long axis and cartilage interface is greater than 74°. There is no difference in the quality of osteochondral grafts harvested from the knee regardless of technique or donor site used. Osteochondral graft diameter should be kept at or less than 7 mm because of the high percentage of unacceptable grafts with increasing chisel sizes.