Cartilage repair techniques of the talus: An update

Table 1 Indications and contraindications for autologous chondrocyte transplantation of the talus (modified to[61])

Indication	Contraindication
symptomatic full-thickness chondral/osteochondral lesions	Osteoarthritis/rheumatoid arthritis
focal lesion > 1.5 cm2 in size	so-called kissing lesions
lesion with necrotic bone/fibrous tissue base	ligamentous instability (can be corrected in conjunction with the ACT procedure)
failed previous traditional surgery	axial malalignment
(i.e., drilling or microfracture)	(should be previously corrected)
patients younger than 45 yr of age	children/teenagers
	patients older than 45 yr of age

ACT: Autologous chondrocyte transplantation.

Table 2 Summary of treatment options for cartilage repair of the talus

Procedure	Concept	Indication	Potential Advantage	Worth knowing	Evidence
Conservative	Unload injured cartilage	Low-grade OD in children	Healing without surgical risk	Results in literature low but recommended first-line treatment in low-grade lesions	Poor
Marrow stimulation techniques	Recruits mesenchymal stem cells from bone marrow Stimulates differentiation of repair tissue	Lesions < 150 mm2 with none/minimal subchondral involvement	Can be administered arthroscopically Can be done repeatedly	Fibrocartilaginous repair tissue Results deteriorate over time	Fair
Autologous osteochondral transplantation	Resurfaces defect with viable hyaline cartilage + underlying bone	Osteochondral defects (2-4 cm2)	Reproduces mechanical, structural, biomechanical characteristics of primary cartilage One-stage procedure	Donor site morbidity Potential need for osteotomy	Fair
Osteochondral allograft transplantation	Resurfaces defect with viable hyaline cartilage + underlying bone	Large-volume/ cystic lesions	No limitations based on size of defect One-stage procedure	Potential decrease in viable chondrocytes due to disease screening	Poor
Autologous chondrocyte transplantation (ACT)	Cultured chondrocyte-like cells will stimulate a hyaline-like repair tissue	Second-line treatment in large defects (> 2 cm2)	Nearly perfect fit with defect (no ”dead spaces”)	Adverse effects of 1st generation MACT with better cell distribution Osseous defect has to be grafted before ACT	Poor
Further treatment options (hyaluronic acid, PRP, mesenchymal stem cells)	Not clear May function as an biological adjunct	Not clear May be added to repair techniques	Not clear May improve final outcome	Mode of function not completely understood	Insufficient

ACT: Autologous chondrocyte transplantation; MACT: Matrix-associated autologous chondrocyte transplantation; OD: Osteochondritis dissecans; PRP: Platelet rich plasma.