When knee cartilage repair is worth consideringCartilage lacks a blood supply and cannot self-heal, but surgical or minimally invasive repair can restore focal defects in otherwise healthy joints, potentially delaying knee replacement by years or decades.Cartilage lacks a blood supply and cannot self-heal, but surgical or minimally invasive repair can restore focal defects in otherwise healthy joints, potentially delaying knee replacement by years or decades.
AMIC vs MACI for knee cartilage repairStandalone microfracture for knee cartilage defects has less than 60% survivorship at three years; AMIC adds a collagen membrane to stabilize repair, whilst MACI uses cultured chondrocytes and shows superiority in the SUMMIT trial for lesions over 3 cm².Standalone microfracture for knee cartilage defects has less than 60% survivorship at three years; AMIC adds a collagen membrane to stabilize repair, whilst MACI uses cultured chondrocytes and shows superiority in the SUMMIT trial for lesions over 3 cm².
MACI versus microfracture for knee cartilage repairMACI outperforms microfracture for knee cartilage defects of 3 cm² or larger, according to the SUMMIT randomised trial, which found significantly greater improvements in pain and function at two years that persisted through five years.MACI outperforms microfracture for knee cartilage defects of 3 cm² or larger, according to the SUMMIT randomised trial, which found significantly greater improvements in pain and function at two years that persisted through five years.
Allograft or Autograft for Large Knee Cartilage DefectsDefect size is the primary determinant in knee cartilage repair: below 4 cm², autograft transfer from low-load zones is standard; above that threshold, cadaveric allograft removes the biological supply ceiling.Defect size is the primary determinant in knee cartilage repair: below 4 cm², autograft transfer from low-load zones is standard; above that threshold, cadaveric allograft removes the biological supply ceiling.
Cartilage repair or knee replacementThe choice between cartilage repair and knee replacement hinges on whether damage is focal or diffuse. Isolated defects in otherwise healthy joints can be repaired; widespread bone-on-bone osteoarthritis affecting multiple compartments requires replacement instead.The choice between cartilage repair and knee replacement hinges on whether damage is focal or diffuse. Isolated defects in otherwise healthy joints can be repaired; widespread bone-on-bone osteoarthritis affecting multiple compartments requires replacement instead.
ACI vs MACI for knee cartilage repairBoth ACI and MACI for knee cartilage repair follow a two-stage structure: cartilage biopsy with laboratory expansion, then implantation. The difference lies in the second stage's delivery mechanism—ACI injects expanded cells beneath a periosteal patch, while MACI pre-seeds them onto a collagen membrane secured with fibrin glue.Both ACI and MACI for knee cartilage repair follow a two-stage structure: cartilage biopsy with laboratory expansion, then implantation. The difference lies in the second stage's delivery mechanism—ACI injects expanded cells beneath a periosteal patch, while MACI pre-seeds them onto a collagen membrane secured with fibrin glue.
When Knee Alignment Must Come Before Cartilage RepairCartilage repair fails in a varus knee because the weight-bearing line runs through the damaged medial compartment instead of the joint's centre. High tibial osteotomy redirects that line toward the centre; expert guidance mandates combined surgery above 3° varus and forbids isolated repair beyond 5°.Cartilage repair fails in a varus knee because the weight-bearing line runs through the damaged medial compartment instead of the joint's centre. High tibial osteotomy redirects that line toward the centre; expert guidance mandates combined surgery above 3° varus and forbids isolated repair beyond 5°.
How ACI and MACI differ for cartilage repairMACI pre-seeds cultured chondrocytes onto a collagen membrane fixed with fibrin glue, eliminating the sutures required in earlier ACI variants. The technique enables arthroscopic implantation and supports faster recovery than open surgical approaches.MACI pre-seeds cultured chondrocytes onto a collagen membrane fixed with fibrin glue, eliminating the sutures required in earlier ACI variants. The technique enables arthroscopic implantation and supports faster recovery than open surgical approaches.
When is it too late for cartilage repair?Once cartilage loss becomes generalised and surfaces contact bone, no restoration procedure works; repair is viable only for focal defects.Once cartilage loss becomes generalised and surfaces contact bone, no restoration procedure works; repair is viable only for focal defects.
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.
Choosing joint preserving surgery before knee replacementOne-compartment knee wear does not automatically mean replacement is next: bracing, osteotomy and focal cartilage repair can reduce pain and delay arthroplasty when alignment and damage remain localised. Microfracture is now usually limited to very small defects, while AMIC, MACI, OATS and OCA are chosen by lesion size, depth and…One-compartment knee wear does not automatically mean replacement is next: bracing, osteotomy and focal cartilage repair can reduce pain and delay arthroplasty when alignment and damage remain localised. Microfracture is now usually limited to very small defects, while AMIC, MACI, OATS and OCA are chosen by lesion size, depth and joint health.
Which knee cartilage repair fits your situationKnee cartilage repair choice is driven by defect size, bone involvement and whether treatment is single-stage or staged. OATS or mosaicplasty uses the patient's own osteochondral plugs for small focal defects of roughly 1 to 4 cm², while OCA uses donor tissue when the defect is larger, post-traumatic or involves…Knee cartilage repair choice is driven by defect size, bone involvement and whether treatment is single-stage or staged. OATS or mosaicplasty uses the patient's own osteochondral plugs for small focal defects of roughly 1 to 4 cm², while OCA uses donor tissue when the defect is larger, post-traumatic or involves significant bone loss. AMIC is a single-stage marrow stimulation with a collagen membrane; MACI takes two stages but has 15- to 17-year follow-up data, while head-to-head AMIC-vs-MACI ev...