The impact of polyglycolide membrane on a tendon after surgical rejoining. A histological and histomorphometric analysis in rabbits.

Tissue response to self-reinforced polyglycolide (SR-PGA) membranes surrounding rejoined rabbit tendons was compared with tissue response to nonenveloped rejoined tendons, with special focus on scar formation and SR-PGA membrane biodegradation process. Both hind legs of 20 skeletally mature rabbits were operated on by transecting the plantaris longus tendons and rejoining the ends with sutures. The right side seams were enveloped with bioabsorbable SR-PGA membranes, while the left sides served as noncovered controls. The follow-up times were 3, 6, 12, and 24 weeks. Scar formation and tissue response to membranes were studied by histological and histomorphometric analysis. Tendon regeneration was most active at 3 weeks. Capillary formation was more prominent in specimens with shorter follow-up times. Membrane degradation induced an inflammatory reaction observed at all follow-up time points. Under polarizing microscopy, birefringent SR-PGA material was seen to vanish almost completely by 24 weeks. SR-PGA membranes had no specific effect on scar formation and there were no differences in the reunion process of the transected tendon ends between the SR-PGA membrane groups and the controls. Inflammatory cells in the SR-PGA membrane groups reflected a tissue reaction to the membrane. When placed in soft tissues, SR-PGA membranes degraded almost completely within 24 weeks.