Arthroscopic second-generation autologous chondrocyte implantation: a prospective 7-year follow-up study

Regenerative techniques, such as autologous chondrocyte implantation (ACI), have emerged as a potential therapeutic option for the treatment of chondral lesions, aiming to recreate a hyaline-like tissue in the damaged articular surface. The clinical application of the regenerative approach is well documented for different types of scaffold but mostly with an evaluation of the clinical outcome at short-term follow-up.

This study was conducted to analyze the clinical outcome obtained with arthroscopic second-generation ACI up to 7 years' follow-up, to assess the durability of the results, and understand its real potential over time.

Case series; Level of evidence, 4.

Sixty-two consecutive patients, 48 men and 14 women with a mean age of 28.1 ± 11.4 years, affected by chondral lesions of the femoral condyles were enrolled and treated with arthroscopic implantation of the bioengineered tissue Hyalograft C. The average size of the defects was 2.5 ± 1.0 cm(2). Patients were evaluated with International Knee Documentation Committee (IKDC), EuroQol visual analog scale (EQ-VAS), and Tegner scores every year for 7 years, and a magnetic resonance imaging evaluation was performed.

A statistically significant improvement was observed in all scores from the basal evaluation to the 84 months' follow-up. The IKDC subjective score increased from 39.6 ± 15.0 to 73.6 ± 18.8 at 12 months; a further slight improvement was observed at 24 months' follow-up (76.5 ± 20.7), and then the results were stable and reached a final 7-year value of 77.3 ± 21.5. Seven cases (11%) failed. A better outcome was obtained in young active men, whereas the worst results were found in degenerative lesions or when previous surgery had been performed. Postoperative magnetic resonance imaging studies in 42 cases revealed a complete filling of the cartilage defect in 57% of the lesions, complete integration of the graft in 62% of cases, intact repair tissue surface in 50%, homogeneous repair tissue structure in 43%, and a graft signal-intensity score that was isointense with the adjacent native cartilage in 43% and 48% of the cases in dual T2-fast spin echo and 3-dimensional gradient echo with fat suppression sequences, respectively.

The analysis of this group of homogeneous patients, prospectively evaluated every year for 7 years, shows that this bioengineered approach with the proper indications may offer good and stable clinical results over time.