Choosing ACI, MACI or single‑stage cell surgeryACI and MACI are two-stage repairs for localised full-thickness cartilage defects, while single-stage techniques place cells or cell-rich material into the defect in one operation. MACI has the strongest long-term follow-up, but single-stage methods still rest mainly on smaller, less comparable series.ACI and MACI are two-stage repairs for localised full-thickness cartilage defects, while single-stage techniques place cells or cell-rich material into the defect in one operation. MACI has the strongest long-term follow-up, but single-stage methods still rest mainly on smaller, less comparable series.