AOSSM/AANA Specialty Day 2020-Osteochondral Allografts

Osteochondral Allografts_ Technical Pearls You May Not Know

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This document provides expert technical tips on performing osteochondral allograft surgery, aimed at improving graft success and surgical outcomes. Key points include flexibility in graft selection, such as using lateral femoral condyle grafts for medial defects and typical average-size male donor patella and trochlea tissue, noting that female donors rarely match male recipients. Surgeons are advised to inspect grafts prior to patient surgery and maintain them wet.<br /><br />Tool familiarity is important since different instruments affect fit and graft handling. Careful preoperative planning of graft size, shape (e.g., plug, snowman, oval), and harvest site is emphasized. The recipient site should be prepared first, followed by donor plug harvest, with use of small k-wires to stabilize multiple grafts during preparation.<br /><br />Achieving perpendicularity between graft and recipient site is crucial, with depth measurement consistency within 1-2 mm as an indicator. Surgeons should "start small and ream up" in hard bone areas to avoid over-preparation and may leave small diseased areas ungrafted, resulting in a mosaicplasty effect with fibrocartilage filling the gap. Avoid plunging through hard bone, a common novice error. Reamings bone debris should be saved for filling cysts or enhancing graft integration.<br /><br />Grafts should be thin, typically 5-8 mm total thickness, contrary to some manuals recommending deeper bone. Harvest sites need not exactly match defect locations anatomically but must be perpendicular. Special instruments or guidewires aid in complex areas like the patella and trochlea. Differences in cartilage thickness between donor and recipient are acceptable, ideally with donor cartilage thicker.<br /><br />Tight graft fit is preferred to avoid extra fixation hardware, with trimming or orbital reaming used to ease fit. If modifications are needed, three techniques for graft removal are sutures, retrograde drills, or dental picks. Measurements should be rechecked before adjustments. Gentle manual compression rather than forceful malleting is recommended to seat the graft, preserving chondrocyte viability. The author notes that graft dislocation is seldom seen.<br /><br />Overall, these pearls focus on meticulous planning, precision, gentleness, and practicality, aiming to optimize osteochondral allograft success in knee cartilage repair.

Keywords

osteochondral allograft

graft selection

lateral femoral condyle

patella tissue

surgical planning

graft preparation

mosaicplasty

graft thickness

graft fit

chondrocyte viability