Complex joint reconstruction and joint transplantation with the FLOCSAT concept-planning and surgical implementation

Abstract

Cartilage defects in adult patients are so far incurable. Fresh osteochondral allograft (OCA) transplantation is based on the insertion of mature, living, mechanically sound hyaline cartilage into an osteochondral defect where it undergoes osseointegration. Intact hyaline cartilage of OCA does not cause immune reactions in the recipient. Many reports show that small OCA have good osseointegration and show good long-term results. These observations have been incorporated into the development of the fresh large (> 10 cm2) osteochondral shell allograft transplantation (FLOCSAT) concept, which is based on the following principles: 1) the thickness of the osseous layer should be kept as thin as possible (target < 6-8 mm) so that the transplant remains stable and fixable. This results in reduced segments of vascularization, simplified ossification and reduced immunogenic bone volume. 2) The bone surface is processed and enlarged (oscillating saw: pie crust technique, drill holes) and areas of sclerosis are simultaneously broken off. 3) Cell reduction and washing out of the bony layer with a pulsatile jet lavage. 4) Prevention of impaction and dessication: cartilage with its living chondrocytes are very sensitive to mechanical contusion and dessication. When introducing the transplant, the tissue must therefore be continually moistened and the pressure acting on the cartilage must be controlled. 5) Stable fixation: extensive uniplanar osteochondral transplants cannot be inserted by the press-fit method; therefore, fixation is carried out with small implants. In this publication we demonstrate how severe and complex posttraumatic or degenerative delayed problems can be solved using FLOCSAT.