BACKGROUND Recent clinical and biomechanical studies have demonstrated better results with double-bundle ACL reconstruction with respect to anterior and rotator stability of the knee when compared to single-bundle reconstruction. Little is known about the healing process after double bundle ACL reconstruction. The objective of this study was to observe the ACL double bundle graft remodeling process in four traumatic failed grafts. These morphological appearances were then correlated to normal tendon allograft and ACL. The hypothesis of the study was that a different maturation process occurs between the two bundles. MATERIALS AND METHODS Four ruptured ACL double bundle reconstructed remnants were obtained from 4 patients undergoing revision surgery. In 2 cases, both bundles were torn, with only the AM bundle torn in the remaining 2 cases. In all patients, the lesion occurred during sport activities at an average follow-up of 11 (9-14) months. Three different intact ligaments (positive control group) was obtained during total knee arthroplasty procedure. Three different tibialis anterior tendon allografts, the same type of graft used for ACL reconstruction, were used as negative control group. Each biopsy was analysed with light and transmission electron microscopy to count the number of cells and to measure the diameter, the density, and the percentage area of collagen fibrils. RESULTS For all the variables analyzed, there was a statistical difference between AM and PL groups and AM and allografts groups (p < 0.05). No difference was observed between AM and ACL groups with exception of collagen fibrils density (p < 0.05). There were differences between PL and allograft groups exclusively for density and area of collagen fibrils and between PL and ACL groups for diameter, density and area of the collagen fibrils (p < 0.05). DISCUSSION The presence of cells, the density and the percentage of area occupied by the collagen fibrils of the two bundles when compared to control groups demonstrate an evolution of the grafts from tendon to ligament. The different maturation stage of the two bundles is suggested by the differences in all the variables considered. The AM portion appears more mature than the PL one. Our results suggest that the grafts are still immature at an average of 11 month postoperatively. Long term prospective randomized studies between single and double bundle reconstruction will likely demonstrate if an anatomic reconstruction is able to restore the normal structure and ultrastructure of the native AM and PL bundles. REFERENCES Yagi et al. 2007, Vidal et al. 2005, Shino et al. 1995, Amiel et al. 1986.
Morphological analysis of failed double bundle ACL grafts
RONGA, MARIO;
2007-01-01
Abstract
BACKGROUND Recent clinical and biomechanical studies have demonstrated better results with double-bundle ACL reconstruction with respect to anterior and rotator stability of the knee when compared to single-bundle reconstruction. Little is known about the healing process after double bundle ACL reconstruction. The objective of this study was to observe the ACL double bundle graft remodeling process in four traumatic failed grafts. These morphological appearances were then correlated to normal tendon allograft and ACL. The hypothesis of the study was that a different maturation process occurs between the two bundles. MATERIALS AND METHODS Four ruptured ACL double bundle reconstructed remnants were obtained from 4 patients undergoing revision surgery. In 2 cases, both bundles were torn, with only the AM bundle torn in the remaining 2 cases. In all patients, the lesion occurred during sport activities at an average follow-up of 11 (9-14) months. Three different intact ligaments (positive control group) was obtained during total knee arthroplasty procedure. Three different tibialis anterior tendon allografts, the same type of graft used for ACL reconstruction, were used as negative control group. Each biopsy was analysed with light and transmission electron microscopy to count the number of cells and to measure the diameter, the density, and the percentage area of collagen fibrils. RESULTS For all the variables analyzed, there was a statistical difference between AM and PL groups and AM and allografts groups (p < 0.05). No difference was observed between AM and ACL groups with exception of collagen fibrils density (p < 0.05). There were differences between PL and allograft groups exclusively for density and area of collagen fibrils and between PL and ACL groups for diameter, density and area of the collagen fibrils (p < 0.05). DISCUSSION The presence of cells, the density and the percentage of area occupied by the collagen fibrils of the two bundles when compared to control groups demonstrate an evolution of the grafts from tendon to ligament. The different maturation stage of the two bundles is suggested by the differences in all the variables considered. The AM portion appears more mature than the PL one. Our results suggest that the grafts are still immature at an average of 11 month postoperatively. Long term prospective randomized studies between single and double bundle reconstruction will likely demonstrate if an anatomic reconstruction is able to restore the normal structure and ultrastructure of the native AM and PL bundles. REFERENCES Yagi et al. 2007, Vidal et al. 2005, Shino et al. 1995, Amiel et al. 1986.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
