The Cartilage Guide

Treatments & Surgery · Comparison

Four ways to resurface a knee, honestly compared

What each procedure actually is, who it suits, and what the follow-up data says — so you can walk into the consult with better questions.

	Microfracturethe old default	MACIcultured chondrocytes	ICC / CEMTRO Cellhigh-density MACI	Agili-Caragonite scaffold
What it is	Awl punctures the bone to bleed marrow into the defect; forms fibrocartilage.	Your own chondrocytes grown on a membrane, implanted in a second surgery.	Same idea, far higher cell density per cm² — the Madrid group's refinement.	Cell-free coral-derived plug the body remodels into cartilage and bone.
Best suited to	Small defects (<2 cm²), lower demand patients.	Larger defects in younger, active knees (the SUMMIT trial enrolled ≥3 cm²).	Similar range; marketed for higher-grade repair tissue.	Osteochondral defects, incl. some knees with mild OA.
Evidence	Strongworks early, but deterioration is documented from ~18 months and failure reaches ~38% at 10 years	Strongbeats microfracture at 2 and 5 years	Promisingcase series, all single-center; published follow-up stops at 24 months	PromisingRCT superiority held at 5 years, but implant failures doubled (7% → 15%) between years 2 and 5
Recovery	6–9 months; strict early protection.	9–12+ months; two operations.	Comparable to MACI.	Single surgery; 6–12 months.
Ask your surgeon	“What happens when fibrocartilage wears?”	“How many have you done, at what defect size?”	“Where's the published follow-up?”	“Am I inside the studied indication?”

Microfracture

the old default

What it is: Awl punctures the bone to bleed marrow into the defect; forms fibrocartilage.
Best suited to: Small defects (<2 cm²), lower demand patients.
Evidence: STRONGworks early, but deterioration is documented from ~18 months and failure reaches ~38% at 10 years
Recovery: 6–9 months; strict early protection.
Ask your surgeon: “What happens when fibrocartilage wears?”

MACI

cultured chondrocytes

What it is: Your own chondrocytes grown on a membrane, implanted in a second surgery.
Best suited to: Larger defects in younger, active knees (the SUMMIT trial enrolled ≥3 cm²).
Evidence: STRONGbeats microfracture at 2 and 5 years
Recovery: 9–12+ months; two operations.
Ask your surgeon: “How many have you done, at what defect size?”

ICC / CEMTRO Cell

high-density MACI

What it is: Same idea, far higher cell density per cm² — the Madrid group's refinement.
Best suited to: Similar range; marketed for higher-grade repair tissue.
Evidence: PROM.case series, all single-center; published follow-up stops at 24 months
Recovery: Comparable to MACI.
Ask your surgeon: “Where's the published follow-up?”

Agili-C

aragonite scaffold

What it is: Cell-free coral-derived plug the body remodels into cartilage and bone.
Best suited to: Osteochondral defects, incl. some knees with mild OA.
Evidence: PROM.RCT superiority held at 5 years, but implant failures doubled (7% → 15%) between years 2 and 5
Recovery: Single surgery; 6–12 months.
Ask your surgeon: “Am I inside the studied indication?”

Full entries: Microfracture · MACI · ICC / CEMTRO Cell · Agili-C