Freeze dried anterior cruciate ligament allografts. Preliminary studies in a goat model.
One ACL in each of 11 mature goats was replaced with a freeze dried bone-ACL-bone allograft. One year following implantation the goats had their knees evaluated biomechanically and for microvascularity and histologic changes. The reconstructed knees had a significantly greater total AP laxity (3.8 +/- 0.6 mm) (mean and SEM) than the controls (1.0 +/- 0.1 mm). Differences in primary AP laxity were responsible for 81% of the difference in total laxity, with only a 0.4 mm difference in secondary laxity. Neutral stiffness in the reconstructive knee was 17% of control, while stiffness at 30 newtons (N) of anterior force was approximately 50% of controls. Ligament stiffness in the linear region for the ACL allograft was 35% of the control value of 686 N/mm. The maximum load of the allografts was 571 +/- 45 N, or 25% of the contralateral ACL control strength (2301 +/- 155 N). Five of the seven allografts failed at the femoral insertion. Both elongation (83%) and energy (21%) to maximum load were less for allografts than controls. Histologic evaluation of the allografts revealed the presence of a regular oriented dense connective tissue which resembled a normal ligament. Microangiography revealed a periligamentous and endoligamentous vascular pattern reminiscent of a normal ACL and complete revascularization of the bone plugs.
Jackson
D W
DW
Southern California Center for Sports Medicine, Long Beach 90806.
Grood
E S
ES
Arnoczky
S P
SP
Butler
D L
DL
Simon
T M
TM
D000818:Animals; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D005260:Female; D005612:Freeze Drying; D006041:Goats; D007719:Knee Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008023:Ligaments, Articular / Q000473:pathology / Q000637:transplantation*