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Autologous cartilage implantation for full thickness articular cartilage defects of the knee

  • Review
  • Intervention




Treatments for managing articular cartilage defects of the knee, including drilling and abrasion arthroplasty, are not always effective. When they are, long-term benefits may not be maintained and osteoarthritis may develop, resulting in the need for a total knee replacement. An alternative is the surgical implantation of healthy cartilage cells into damaged areas (autologous cartilage implantation).


To determine the effectiveness of autologous cartilage implantation (ACI) in people with full thickness articular cartilage defects of the knee.

Search strategy

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (15 December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2005), MEDLINE (1966 to December 2005), CINAHL (1982 to December Week 2, 2004), EMBASE (1988 to 2005 Week 50), SPORTDiscus (1830 to January 2005) and the National Research Register Issue 3, 2005.

Selection criteria

Randomised and quasi-randomised trials comparing ACI with any other type of treatment (including no treatment or placebo) for symptomatic cartilage defects of the medial or lateral femoral condyle, femoral trochlea or patella.

Data collection and analysis

Two review authors selected studies for inclusion independently. We assessed study quality based on adequacy of the randomisation process, adequacy of the allocation concealment process, potential for selection bias after allocation and level of masking. Data was not pooled due to clinical and methodological heterogeneity in the studies.

Main results

We included four randomised controlled trials (266 participants). One trial of ACI versus mosaicplasty reported statistically significant results for ACI at one year, but only in a post-hoc subgroup analysis of participants with medial condylar defects; 88% had excellent or good results with ACI versus 69% with mosaicplasty. A second trial of ACI versus mosaicplasty found no statistically significant difference in clinical outcomes at two years.

There was no statistically significant difference in outcomes at two years in a trial comparing ACI with microfracture. In addition, one trial of matrix-guided ACI versus microfracture did not contain enough long-term results to reach definitive conclusions.

Authors' conclusions

The use of ACI and other chondral resurfacing techniques is becoming increasingly widespread. However, there is at present no evidence of significant difference between ACI and other interventions. Additional good quality randomised controlled trials with long-term functional outcomes are required.

Plain language summary

Autologous cartilage implantation for full thickness articular cartilage defects of the knee

A layer of cartilage covers the knee joint surfaces to decrease friction and mechanical load on the joint. Damage or breakdown of the cartilage (articular surface) can decrease mobility of the joint and cause pain on movement and continuing deterioration may lead to early onset osteoarthritis. Treatments include relieving symptoms, surgically cleaning up the joint, or surgically re-establishing the cartilage layer. The latter is done using marrow stimulation techniques (such as abrasion arthroplasty, drilling and microfracture), mosaicplasty (also known as osteochondral cylinder transplantation), and more recently with implantation of healthy cartilage cells (chondrocytes). These are grown in culture from healthy cells taken from the joint (autologous cartilage implantation) in an effort to improve the wear characteristics of the new cartilage layer. The authors searched the medical literature and included four controlled studies. Although there are some promising results for autologous cartilage implantation from one trial, the evidence on benefits compared with other treatments is lacking. Key issues relate to medium- to long-term outcomes and the durability of different types of chondral repair. Complications of surgery and rehabilitation are also important considerations.