A high-strength Dacron augmentation for cruciate ligament reconstruction. A two-year canine study.

Augmentation and substitution grafting was performed in 48 adult canine stifles after anterior cruciate ligament resection. Four surgical reconstructions were performed: substitution in over-the-top fashion intra-articularly with just the Dacron implant; intra-articular substitution with tibial and femoral drill holes; over-the-top substitution intra-articularly and extra-articularly with the Dacron graft augmenting the iliotibial band wraparound transfer; and two-band extra-articular Dacron substitution with the Coker modification of the MacIntosh extra-articular reconstruction without iliotibial band. Sacrifice was performed at six, 12, 24, and 36 weeks postoperation with each specimen submitted for histologic or tensile strength testing. Four canines incurred infection and were omitted from follow-up study. Examination at six and 12 weeks revealed no graft breakage, stable knees, and no evidence of degenerative change radiographically in stifles. Fibrous ingrowth was present in the intra-articular substitution and augmentation stifles. No loss of ultimate failure strength was noted during failure mode testing. The direct substitution procedure revealed some evidence of cutting-edge disruption in 24-week canines. Beveling the drill holes could eliminate this problem. Follow-up evaluation of the augmentation techniques at 24 weeks revealed increased preservation of the iliotibial band-wrapped graft by a higher degree of fibrous ingrowth. No further loss in tensile strength of the graft was noted; concurrently, no increase in tensile strength was appreciated. The use of high-tensile-strength Dacron as an augmentation to biologic transfer appears to offer significant promise as a technique for human application. The study is continuing for long-term durability of the augmentation graft.