Remodeling of Articular Defects in an Animal Model

Abstract

When treating displaced intraarticular fractures, the goal has been to restore normal articular cartilage contour to decrease local contact stresses that may lead to the development of posttraumatic osteoarthritis. To confirm observations that articular cartilage step-offs can remodel with time and to determine how the articular surface and subchondral bone remodels after an intraarticular fracture, joint surface changes were examined in a weightbearing sheep model with an intraarticular fracture. Articular surface pressure changes were observed across a 1-mm osteotomy. Twelve weeks after an intraarticular osteotomy, there was a decrease in differential pressure distribution between the normal articular cartilage and the depressed articular surface. Histologic analysis showed thinning of the articular cartilage on the high side of the osteotomy with collagen compression and bending of the collagen fibrils. On the low side of the osteotomy, increased chondrocyte cellularity and hypertrophy were observed. In addition, bending of collagen fibrils was observed in an unloaded state in an attempt to form a smooth overlapping shelf at the osteotomy site. Because intraarticular incongruency, with resultant joint contact pressure differences, seems to be involved in the development of posttraumatic arthritis, methods to improve cartilage remodeling may improve outcome after intraarticular fractures.

Repair of porcine articular cartilage defect with a biphasic osteochondral composite

“…50 However, most models of ACI involve uniform distribution of implanted cells in order to minimize local hypertrophy, 51 and this uniformity would be expected to be preserved in the regenerate cartilage. Although cartilage may undergo remodeling as a result of the mechanical stimulus of normal joint activity, 52,53 natural chondrocyte distribution was not seen in our study.…”

Post‐traumatic osteoarthritis: Improved understanding and opportunities for early intervention

“…These studies generally mirror the results of impaction of cartilage explants and of ex vivo human joints,18 though they require much higher stresses to reproduce the injury in an intact joint. Other investigators examined the effects of an intra-articular osteotomy with varying degrees of articular displacement, but without articular loading or cartilage impaction, finding that inter-fragmentary compression may enhance articular fracture repair, and that remodeling of the articular surface can occur on a limited basis 19–21. A third area of investigation has involved the creation of an intra-articular fracture via in vivo loading of the joint.…”

Comparison of Articular Cartilage Repair by Autologous Chondrocytes With and WithoutIn VitroCultivation

“…43 However, most models of ACI prefer uniform seeding of cells to avoid local hypertrophy of regenerate tissue. 44 Although cartilage may remodel by mechanical stimulus of normal joint activity, 45,46 the natural distribution of chondrocytes did not build in our animals.…”