Abstract
Background
Meniscal tears are among the most common knee injuries. To preserve as much as possible the joint, partial and total meniscal replacements are necessary. To combine the biocompatibility and mechanical resistance of meniscus allograft with the disponibility of synthetic substitutes, an acellular, viroinactivated and sterile scaffold with well-preserved structure has been developed based on PHOENIX process.
Methods
Human menisci were collected from living donors undergoing total knee arthroplasty. They underwent chemical treatments, freeze-drying and gamma irradiation. Decellularisation of menisci and preservation of the matrix structure were explored by histological studies. Meniscal scaffold ultrastructure was analysed by scanning electron microscopy. Biomechanical studies were also conducted. Scaffold viroinactivation was investigated by viral clearance studies. Finally, the allografts were cultured for 4 weeks with Mesenchymal Stem Cells (CSM); cells viability and proliferation were assessed histologically and by confocal microscopy following stainings.
Results
Histological data evidenced that the process led to complete decellularisation of the menisci, high porosity within the tissue and to the removal of glycosaminoglycans, present in the center of native menisci. The meniscal surface as well as collagen fibers were preserved as assessed by electron scanning microscopy. Ultimate tensile strengths of native and processed menisci were similar. Viral clearance studies showed that each viral inactivation step induced a viral load reduction compliant with the reduction factor specified in the European guidelines. CSM exhibited great viability and proliferation at the surface of the allograft and partial penetration inside.
Conclusions
Scaffold safety is conferred by decellularisation and viroinactivation of the meniscus while preserving structure and mechanical resistance of the tissue, enabling cells to proliferate around and inside the allograft. Freeze-drying and gamma irradiation make it a ready-to-use product, with different sizes for partial and total meniscal replacement.
