Experimental hemijoint and whole-joint transplantation

Area of Science:

• Orthopedic surgery
• Transplantation immunology
• Biomaterials science

Background:

• Autologous hemijoint transplants maintain viability but may deteriorate over time.
• Allogeneic transplants face immune rejection, with fresh grafts containing subchondral bone being rapidly rejected.
• Frozen allografts with limited subchondral bone may initially maintain configuration but eventually degenerate.

Purpose of the Study:

• To evaluate the long-term viability and function of autologous and allogeneic joint transplants.
• To investigate the impact of revascularization on the survival and biological performance of osteochondral grafts.
• To compare the outcomes of vascularized versus nonvascularized joint allografts.

Main Methods:

• Assessment of autologous hemijoint transplants for biologic viability and joint surface integrity.
• Evaluation of allogeneic transplants (fresh and frozen) with varying subchondral bone content.
• Analysis of canine whole knee transplants, including immediately revascularized autografts and allografts with immunosuppression.
• Histological examination to identify bony and cartilaginous necrosis in revascularized grafts.

Main Results:

• Autologous hemijoint transplants demonstrate initial viability but potential long-term deterioration.
• Fresh allografts with substantial subchondral bone lead to rapid immune rejection.
• Immediately revascularized canine autografts sustained normal biologic function for up to five years.
• Revascularized allografts with immunosuppression survived up to 18 months, though focal necrosis occurred.
• Revascularized osteochondral grafts proved biologically superior to nonvascularized grafts.

Conclusions:

• Revascularization is critical for the long-term success of both autologous and allogeneic osteochondral grafts.
• While autografts offer good results, revascularization enhances their biologic function.
• Successfully revascularized allografts demonstrate improved survival, but immune challenges and necrosis remain concerns.
• The findings support the superiority of vascularized osteochondral grafts in joint transplantation.