Attachment of periosteal grafts to articular cartilage with fibrin sealant.

Abstract

Favorable results using fibrin sealants in vascular surgery and soft tissue reconstruction have prompted investigation of these biologic adhesives for orthopedic applications. One important recent application was as a sealant for periosteal grafts applied to defects in articular surfaces, a procedure that contained injected chondrocytes cultured in vitro. The low and variable adhesive strength of autologous fibrin substances prompted our investigation of allogeneic fibrin. An in vitro test method was developed to investigate the use of a fibrin sealant for attaching periosteal (bovine) patches to articular cartilage (bovine). Dermis-dermis (porcine) adhesion also was evaluated. In tests of the periosteum-to-cartilage bond performed in a physiological environment, we determined the effects of the following variables on the adhesive shear strength: set time, source of fibrinogen (bovine versus human), and fibrinogen concentration. A specially designed test rig was developed to avoid nonshear force components. Adhesive shear strength increased with fibrin set time for both fibrinogen concentrations and sources (p <.03). The 30-min set time yielded data with less variance than the 5-min set time in all cases except with the higher human fibrinogen concentration (50-80 mg/mL). While there was a trend at each set time towards greater shear strength with increased protein concentration (50-80 mg/mL versus 25-40 mg/mL), only the 5-min trial of the bovine product provided a significant advantage (p <.006). There was no significant difference in adhesive strength between the fibrin products produced with human and bovine fibrinogen. The periosteum-cartilage adhesive strengths obtained in our model were comparable to values recorded for the dermis-dermis bonding. The greater strength at the 30-min set time suggests that a certain time period of joint immobilization might be beneficial in procedures in which grafts are glued to articular cartilage. This study has shown that adhesive strengths achieved with fibrin glues in treating skin wounds also can be achieved in the attachment of periosteal grafts to articular cartilage.