Novel nano-composite biomaterial for osteochondral tissue engineering: pilot clinical study at 2 years follow up

Objectives: Current surgical techniques to repair osteochondral defects lead to poor subchondral bone regeneration and fibrocartilage formation, often associated with joint pain and stiffness. From a surgical and commercial standpoint, an ideal graft for osteochondral defect repair would be an off-the-shelf product; thus, some new biomaterials were recently proposed to induce ‘‘in situ’’ cartilage regeneration after direct transplantation onto the defect site. We performed this clinical pilot study where a newly developed biomimetic scaffold was used for the treatment of chondral and osteochondral lesions of the knee joint in order to evaluate the safety and the reproducibility of the surgical procedure and to test the intrinsic potential of the device without any other cells culture. Methods: A gradient composite O.C. scaffold, based on type-I collagen- HA, was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles at physiological conditions30 cases (9F, 21M, mean age 29,3 years) with knee osteochondral lesions (8 medial femoral condyle, 5 lateral condyle, 12 patella, 8 femoral troclea) were treated with scaffold implantation from January 2007 to July 2007. The lesions size went from 2 cm2 to 6 cm2. The clinical outcome of all patients was analyzed prospectively, at 6 moths at 1 year and 2 years using the Cartilage standard Evaluation Form as proposed by ICRS and an high resolution MRI . Results: Statistical analysis demonstrated a significant improvement (Non Parametric paired Wilcoxon test, p\0.0005) from pre-operative to 12 and 24 months follow up. IKDC objective score showed preoperatively 46.1% of normal or nearly normal knees and 79.3% of normal or nearly normal knees at 24 months. Statistical analysis showed a significant improvement in the IKDC subjective score from pre-operative (37,5±14,6) to 24 months follow up (82,4±11,9) (Non Parametric paired Wilcoxon test, p\0.0005). MRI evaluation in at 12 months was analyzed according to the MOCART scoring scale. The complete filling of cartilage defect was noted in 86.2% of the patients and the congruency of the articular surface was seen in same patients.1 case failed and were reoperated. Conclusions: This open one-step surgery was used for the treatment of chondral and osteochondral defects. The results of this technique at short follow-up are very encouraging and show satisfactory results even in big ostechondral defects.