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Osteochondral defect of the knee treatment: what does the evidence say?

Discover the best osteochondral defect of the knee treatment options based on long-term outcomes from a major scientific meta-analysis.

Injuries to the cartilage and underlying bone of the knee, known as osteochondral defects, pose a significant therapeutic challenge. As new techniques continue to emerge, choosing the most effective and safest treatment of osteochondral defect of the knee remains a critical question for surgeons and patients alike.  

This article summarises findings from the study “Microfractures, autologous matrix-induced chondrogenesis, osteochondral autograft transplantation and autologous chondrocyte implantation for knee chondral defects: a systematic review and network meta-analysis of randomized controlled trials” published in EFORT Open Reviews (2024) and led by Prof. Cavaignac alongside other professionals.

To explore more high-level comparative studies, consider reading the other publications by Professor Cavaignac.

Osteochondral lesions of the knee treatment options

Choosing an osteochondral lesion of the knee treatment depends on several factors including lesion size, bone involvement and patient activity level. The review analysed four main options:

  • Microfractures (MF)
  • Autologous matrix-induced chondrogenesis (AMIC)
  • Osteochondral autograft transplantation (OCT)
  • Autologous chondrocyte implantation (ACI), including all three generations and chondrospheres

These options represent the most common approaches to osteochondral knee injury treatment. Each has unique mechanisms, from stimulating bone marrow to implanting lab-cultured cells.

Microfracture and AMIC: first-line for smaller defects

Microfracture and autologous matrix-induced chondrogenesis (AMIC) are widely used in osteochondral defect of the knee conservative treatment, particularly when the lesion is small and there is no significant bone involvement. These methods stimulate the body's natural healing by encouraging the formation of fibrocartilage. However, fibrocartilage lacks the biomechanical properties of native cartilage and may not provide durable results in highly active patients.

Osteochondral autograft transplantation (OCT)

OCT is best suited for small-to-medium lesions where bone involvement is present. It involves transferring cartilage and bone plugs from less weight-bearing areas to the damaged zone. The technique is technically demanding but offers hyaline-like cartilage repair, which is biomechanically superior to fibrocartilage.

Autologous chondrocyte implantation (ACI): from ACI1 to chondrospheres

ACI has evolved through generations:

  • ACI1: cells injected under a periosteal flap.
  • ACI2: same principle but using a collagen membrane.
  • ACI3 (also known as MACI): cells embedded in a scaffold.
  • Chondrospheres: scaffold-free cell clusters produced by chondrocytes themselves.

According to the study, chondrospheres were the only method in knee osteochondral lesion treatment associated with a significantly lower rate of failure and reoperation.

Clinical outcomes: is there a superior osteochondral defect treatment for the knee?

One of the most striking findings of the meta-analysis is that no osteochondral defect treatment for the knee showed superiority in terms of patient-reported outcome measures (PROMs) over short (<1 year), mid-term (1–5 years) or long-term (>5 years) follow-up. In short, regardless of the method, functional outcomes were statistically equivalent when considering focal chondral defect treatment.

This suggests that while options may differ in safety and cost, their effectiveness in restoring knee function is broadly similar. Therefore, the choice often depends on other factors such as lesion size, previous surgery, cost and surgeon expertise.

Safety profiles and complications

Although PROMs were comparable across all osteochondral lesion of the knee treatment options, there were differences in safety outcomes. Notably, chondrospheres emerged as the most favourable in terms of lower failure and reoperation rates in osteochondral lesion treatment of the knee. Specifically, chondrospheres outperformed ACI1, ACI2, AMIC, OCT and microfracture in 4–6 pairwise comparisons.

However, it is important to interpret these results with caution. Adverse event reporting was heterogeneous and sometimes incomplete. Most of the data on chondrospheres came from a limited number of trials, which may limit the generalisability of the findings.

What is the best osteochondral injury of the knee treatment?

Based on the study, here is a simplified report to help select the most appropriate osteochondral injury of the knee treatment:

  • Small defects, no bone loss: Microfracture, AMIC or ACI
  • Small defects with bone loss: OCT
  • Medium to large defects: ACI, with or without bone grafts
  • High priority on safety: Chondrospheres may be considered, particularly when avoiding revision is critical

In clinical practice, these decisions are rarely made in isolation. Surgeons must also consider prior interventions, patient-specific anatomical features and post-operative rehabilitation protocols.

Conclusion and findings

While no technique has demonstrated clear superiority in function restoration, chondrospheres may offer an advantage in terms of safety, especially regarding failure and reoperation rates. More robust trials with standardised outcomes are needed to confirm these trends. For patients and clinicians seeking the most effective and personalised care in osteochondral knee treatment, evidence-based decision-making remains essential.

Professor Étienne Cavaignac remains a trusted leader and surgeon in knee osteochondral defect treatment, known for his expertise, clinical rigour and patient-centred approach.

Written by : Pr Etienne Cavaignac

Published on :

June 4, 2025

Updated on :

June 4, 2025
Copyright 2025 - Pr Étienne Cavaignac