Previous studies in our laboratory showed that acellular collagen scaffold implants induce tissue ingrowth and perform similar to autografts following reconstruction of rabbit Achilles tendon or anterior cruciate ligament (ACL). We chronologically review these and related studies, and report preliminary development of fibroblast-seeded collagen scaffolds potentially useful for ACL reconstruction. The ‘healing potential’ of fibroblasts was measured within collagen scaffolds in vitro, as a function of fibroblast source. Aligned collagen scaffolds were seeded with fibroblasts from rabbit ACL, synovium, patellar tendon, or skin. Fibroblast viability, adherence, spreading, proliferation, and protein and collagen deposition were measured on collagen scaffolds. The fibroblasts attached to the scaffolds, and spread along the long axis of the collagen fibers. ACL fibroblasts adhered better than other fibroblast types; however, the ACL fibroblasts proliferated at the slowest rate. Patellar tendon fibroblasts proliferated at the most rapid rate. All four of the fibroblast types secreted protein and collagen within the collagen scaffolds.
Preliminary in vivo studies suggest that fibroblasts seeded onto collagen scaffolds can remain viable following reimplantation into the donor rabbit. Ongoing studies will elucidate the role of autogenous seeded fibroblasts in neoligament formation/remodeling. These ‘ligament analogs’ are potentially useful for clinical ACL reconstruction: fibroblasts would be obtained from biopsy, cultured, seeded onto a collagen scaffold, and implanted as an ACL substitute into the same patient.