Table 1.

Indications for ACI.

Defect stage	•Full-thickness, symptomatic cartilage defect grade 3 and 4 as per ICRS
	•Osteochondritis dissecans stage 3 and 4 as per ICRS-OCD, possibly in combination with subchondral bone reconstruction
Defect size	•Minimum: 2.5–3 cm2
	•Maximum: no limitation
Defect localization	No limitation
	•Medial and lateral femoral condyle
	•Medial and lateral tibial plateau
	•Patellar bearing surface (trochlea)
	•Patella
Age	•Typically up to 55 years of age
	•Higher age is however not a contraindication with relevant defect morphology and primarily intact joint conditions
	•Children and adolescents possible
Contra-indications	•Concomitant pathologies which cause it, which cannot be treated in parallel (e.g. misalignment)
	•Advanced arthritis
	•Subtotal resected meniscus in an impacted compartment
	•Rheumatoid arthritis with relevant synovitis
	•Hemophilia-associated arthropathy

ACI; autologous chondrocyte implantation.