Correspondence (letter to the editor): Tried and Tested Recommendations

The benefits of the microfracturing technique in the medium to long term are questionable. This applies particularly to cartilage lesions larger than 4 cm² (1). Osteochondral transfer methods—for example, mosaicplasty—yield good results even in the longer term. If lesions exceed 4 cm² in size, however, the complication and failure rates associated with this approach increase substantially (2). This finding generally does not apply to autologous chondrocyte transplantation (ACT) (2).

A study with an evidence level of 1, which compared conventional ACT (using quality assured chondrocytes) versus microfracturing, yielded significantly better histological results after ACT. Clinically, too, some of the 3 year results for ACT were significantly superior to those achieved by microfracturing. Another randomized study investigating a carrier-based ACT versus microfracturing reported significantly better results for ACT for all clinical scores after only 2 years. A recently published study with up to 20 years’ follow-up also points at stable long-term results from ACT and a high degree of patient satisfaction (3). However, similarly reliable long-term results after microfracturing, especially for larger cartilage lesions, have not been reported so far, and neither have mainly good results of this method subsequent to failed ACT or mosaicplasty. In sum, the evidence base for ACT—especially in contrast to microfracturing—has improved steadily in the recent past. Our working group’s recommendations for indications and methods for the different biological reconstructive approaches (microfracturing, mosaicoplasty, and ACT) for cartilage lesions of the knee have thus become tried and tested, or even been confirmed, and should therefore continue to be considered in everyday clinical practice (2).