Arthroscopic second generation autologous chondrocytes implantation associated with bone grafting for the treatment of knee osteochondritis dissecans: Results at 6 years

New trends for knee cartilage regeneration: from cell-free scaffolds to mesenchymal stem cells

In the last decade, huge steps forward have been made in the field of cartilage regeneration. The most recent trend for treating chondral/osteochondral lesions is based on the application of smart biomaterials that could lead to "in situ" regeneration of not only cartilage, but also subchondral bone, preferably through a single step procedure to reduce the costs and the morbidity for the patient. This innovative approach is currently under investigation as several "scaffolds" have been proposed in clinical practice, with or without the aid of cells, with the opportunity, in the second case, of bypassing the strict limits imposed by cell manipulation regulations. Furthermore, the fascinating potential of mesenchymal stem cells has recently opened new paths of research to discover how and whether these powerful entities can really contribute to tissue regeneration. The first clinical trials have been published but further high quality research is needed to understand their mechanisms of action, their limits, and their clinical efficacy.

Second-generation arthroscopic autologous chondrocyte implantation for the treatment of degenerative cartilage lesions

PURPOSE

Degenerative cartilage lesions present a negative joint environment, which may have a negative effect on the process of cartilage regeneration. The aim of this study is to analyze the clinical outcome obtained with the treatment for isolated degenerative knee cartilage lesions by second-generation arthroscopic autologous chondrocyte implantation (ACI).

METHODS

Fifty-eight consecutive patients affected by focal degenerative chondral lesions of the femoral condyles and trochlea were treated by second-generation arthroscopic ACI. The mean age at surgery was 34.7 ± 9.1 years and the average defect size was 2.3 ± 0.9 cm(2). The patients were prospectively evaluated with IKDC, EQ-VAS, and Tegner scores preoperatively, at 2 and 6 years.

RESULTS

A statistically significant improvement was observed in all scores from the basal evaluation to the final follow-up. The IKDC subjective score improved from 39.3 ± 13.6 to 68.8 ± 22.7 and 68.5 ± 23.9 at the 2- and 6-year follow-ups, respectively, with a significant improvement (P < 0.0005) and stable results over time; the same trend was confirmed by the EQ-VAS and Tegner scores. The worst results were found in patients with a low physical activity level, women, and those having undergone previous surgery, whereas the symptom duration before surgery did not influence the final outcome. The failure rate was 18.5%.

CONCLUSIONS

Despite a significant improvement, the results were lower with respect to the outcome reported in different study populations, and the number of failures was markedly higher, too. Tissue-engineered cartilage implantation is a promising approach for the treatment of degenerative chondral lesions, but graft properties, besides mechanical and biochemical joint environment, have to be improved.

LEVEL OF EVIDENCE

Case series, Level IV.