The Journal of Bone and Joint Surgery, Vol 73, Issue 4 561-574, Copyright © 1991 by Journal of Bone and Joint Surgery, Inc
Regeneration of Achilles tendon with a collagen tendon prosthesis. Results of a one-year implantation study
YP Kato, MG Dunn, JP Zawadsky, AJ Tria and FH Silver
Department of Pathology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854.
We previously reported on the short-term biocompatibility of a
reconstituted type-I collagen prosthesis that had been tested in the
Achilles tendons of rabbits. Preliminary results indicated that, by ten
weeks after implantation, carbodiimide-cross-linked implants had been
replaced by neotendon in a manner that was similar to that of autogenous
tendon grafts that had been used as controls. Also by ten weeks after
implantation, glutaraldehyde-cross-linked collagen implants were
encapsulated and appeared to have caused an acute inflammatory response. In
the present study, carbodiimide and glutaraldehyde-cross-linked collagen
implants and autogenous grafts that served as controls were implanted for
fifty-two weeks as a replacement for a three-centimeter section of the
Achilles tendon of rabbits. The absence of a crimp in a cross-linked
implant and the presence of a crimp in normal tendon and in tendon that
formed after an implant had been resorbed made it possible to distinguish
between a cross-linked implant and new host tendon that had replaced the
implant after it was resorbed. New collagen that had replaced the implant
and autogenous (control) tendon graft were compared with normal Achilles
tendon with respect to the angle and length of the crimp. The autogenous
grafts and the carbodiimide-cross-linked collagen implants had been
completely resorbed and replaced by neotendon. The neotendon that was
present fifty-two weeks after implantation was similar, but not identical,
to normal tendon. In contrast, the glutaraldehyde-cross-linked implant was
essentially inert, had not been resorbed, and was surrounded by a capsule
of collagenous connective tissue. The neotendon in the capsule was also
similar, but not identical, to normal tendon. There were more cells in the
capsule than in the autogenous grafts or in the carbodiimide-cross-linked
implants. The results of the present study indicate that rapid repair is
achieved with a carbodiimide-cross-linked collagenous implant that has a
structure and mechanical properties that are similar to those of an
autogenous tendon graft and that biodegrades at a similar rate. Prolonged
biodegradation of a glutaraldehyde-cross-linked collagenous implant results
in formation of a capsule and only limited formation of neotendon.