Resorbable scaffolds to promote cartilage regeneration

Abstract

A load-sharing resorbable scaffold is used to help transplanted chondrocytes or other cells generate new cartilage in a damaged joint such as a knee, hip, or shoulder. These scaffolds use two distinct matrix materials. One is a relatively stiff matrix material, designed to withstand and resist a compressive articulating load placed on the joint during the convalescent period, shortly after surgery. Due to the requirement for relatively high stiffness, this material must be denser and have less pore space than other matrices, so it will not be able to support highly rapid cell proliferation and cartilage secretion. The second material comprises a more open and porous matrix, designed to promote maximal rapid generation of new cartilage. In one preferred geometric arrangement, the stiffer matrix material is used to provide an outer rim and one or more internal runners, all of which can distribute a compressive load between them. The rim and runners create a cluster of internal cell-growing compartments, which are filled with the porous and open matrix material to encourage rapid cell reproduction and cartilage generation. These improved scaffolds can also have an articulating outer membrane with certain traits disclosed herein, bonded to and resting upon the upper edges of the runners and rim. The scaffold will support the membrane with a degree of stiffness and resiliency that allows the membrane to mimic a healthy cartilage surface. These scaffolds can be made of flexible materials, to allow them to be inserted into a damaged joint using arthroscopic methods and tools.