Outcomes of Autograft versus Allograft in Pediatric Knee Osteochondral Defects

Autograft (Mosaicplasty) Outcomes

The American Academy of Orthopaedic Surgeons recommends autograft transplantation for pediatric patients with small to medium-sized defects, providing excellent clinical outcomes with immediate restoration of hyaline cartilage in a single procedure 1, 4
Autografts are indicated for patients under 45 years with focal, full-thickness lesions <3 cm² in size without signs of osteoarthritis, with advantages including elimination of need for second surgical procedure, superior mechanical properties, and immediate or near-immediate weight bearing after surgery 1
The main limitation of autografts is donor site morbidity, which can be minimized by careful harvest technique and limiting the number of plugs taken 2, 5

The American Academy of Orthopaedic Surgeons recommends allograft transplantation for larger osteochondral defects in pediatric patients, demonstrating excellent clinical results 2
Allografts are indicated for patients ≤50 years with defects >2.5 cm² or with substantial subchondral bone loss, with advantages including elimination of donor site morbidity and provision of immediate mechanically functional joint surface 2, 5
However, allografts have limitations, including risk of disease transmission and relative paucity of donor tissue 2, 5

For lesions <2 cm², the American Academy of Orthopaedic Surgeons recommends autograft (mosaicplasty) as the first-line treatment, with osteochondral allograft (single plug) or microfracture as second-line options 3
For lesions 2-6 cm², osteochondral allograft is recommended as the first-line treatment, with osteochondral autograft (for lesions closer to 2 cm²) as a second-line option 3
For lesions >6 cm², osteochondral allograft is preferred due to donor site limitations with autograft 3

Proper patient selection is crucial for success and long-term graft viability, regardless of technique chosen, and fresh allografts should be used within 28 days to maintain chondrocyte viability 2
Both autograft and allograft techniques provide hyaline cartilage, which has superior mechanical properties compared to fibrocartilage resulting from microfracture techniques 1, 2