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

Objectives: Current surgical techniques to repair osteochondral defectslead to poor subchondral bone regeneration and fibrocartilage formation,often associated with joint pain and stiffness. From a surgical and commercialstandpoint, an ideal graft for osteochondral defect repair would bean off-the-shelf product; thus, some new biomaterials were recently proposedto induce ‘‘in situ’’ cartilage regeneration after direct transplantationonto the defect site. We performed this clinical pilot study where a newlydeveloped biomimetic scaffold was used for the treatment of chondral andosteochondral lesions of the knee joint in order to evaluate the safety andthe reproducibility of the surgical procedure and to test the intrinsicpotential 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 hydroxyapatitenanoparticles at physiological conditions30 cases (9F, 21M, mean age29,3 years) with knee osteochondral lesions (8 medial femoral condyle, 5lateral condyle, 12 patella, 8 femoral troclea) were treated with scaffoldimplantation from January 2007 to July 2007. The lesions size went from 2cm2 to 6 cm2. The clinical outcome of all patients was analyzed prospectively,at 6 moths at 1 year and 2 years using the Cartilage standardEvaluation Form as proposed by ICRS and an high resolution MRI .Results: Statistical analysis demonstrated a significant improvement (NonParametric paired Wilcoxon test, p.0005) from pre-operative to 12 and24 months follow up. IKDC objective score showed preoperatively 46.1%of normal or nearly normal knees and 79.3% of normal or nearly normalknees at 24 months. Statistical analysis showed a significant improvementin the IKDC subjective score from pre-operative (37,5±14,6) to 24 monthsfollow up (82,4±11,9) (Non Parametric paired Wilcoxon test, p.0005).MRI evaluation in at 12 months was analyzed according to the MOCARTscoring scale. The complete filling of cartilage defect was noted in 86.2%of the patients and the congruency of the articular surface was seen insame patients.1 case failed and were reoperated.Conclusions: This open one-step surgery was used for the treatment ofchondral and osteochondral defects. The results of this technique at shortfollow-up are very encouraging and show satisfactory results even in bigostechondral defects.