Replacement of the anterior cruciate ligament using a synthetic prosthesis. An evaluation of graft biology in the dog.

The ACL of 21 adult mongrel dogs was replaced with a knitted dacron velour prosthesis. The biologic fate of these synthetic grafts was then evaluated at various intervals from 1 to 12 months postoperatively using routine histology and a vascular injection (Spalteholz) technique. Following implantation the knitted dacron prosthesis was encapsulated with a vascular synovial tissue in a manner similar to that observed with autogenous patellar tendon grafts. This revascularization process was followed by a proliferation of fibroblasts throughout the extent of the prosthesis. While the grafts appeared to support a fibrous tissue proliferation in and around the design of the prosthesis, this tissue demonstrated only a random orientation of collagen fibers as late as 1 year postoperatively. It would appear, therefore, that although the knitted dacron prosthesis is capable of inducing and supporting tissue encapsulation and ingrowth, it does not allow for the functional orientation of this tissue.