The effect of cranial cruciate ligament insufficiency on caudal cruciate ligament morphology: An experimental study in dogs.
OBJECTIVE
To investigate the effect of cranial cruciate ligament (CrCL) insufficiency on morphology of the canine caudal cruciate ligament (CdCL).


METHODS
In vivo experimental study.


METHODS
Five adult foxhounds.


METHODS
Two years after CrCL transection, the histologic appearance of CdCLs from CrCL-deficient and unoperated contralateral control (CrCL-intact) stifle joints were evaluated using light and transmission electron microscopy.


RESULTS
CdCLs from CrCL-deficient joints had extracellular matrix changes, characterized by chondroid metaplasia and disruption of cell architecture. Percent of small-diameter fibrils in CdCLs from CrCL-deficient joints was significantly greater (P <.05) than that in CdCLs from CrCL-intact joints. Collagen fibril density in CdCLs from CrCL-deficient joints (41.09 +/- 5.39%) tended to be less than that in CdCLs from CrCL-intact joints (52.96 +/- 6.92%); however, this difference was not significant (P =.056). Mean eccentricity (ratio of minor to major diameters) of collagen fibrils was significantly (P <.0001) lower for CdCLs from CrCL-deficient joints (0.85 +/- 0.016) when compared with that for CdCLs from CrCL-intact joints (0.87 +/- 0.015).


CONCLUSIONS
Significant alterations were found in the morphology of CdCLs from CrCL-deficient joints. These changes may be associated with repetitive microtrauma to the CdCL secondary to instability or enzymatic degradation in the hostile synovial environment of an unstable joint.


CONCLUSIONS
Regardless of the cause, the switch to a predominantly small-diameter collagen fibril profile may reflect compromised material properties of the CdCL. This should be taken into account when considering surgical techniques that rely on the CdCL to stabilize CrCL-deficient stifles.
Zachos
Terri A
TA
Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, East Lansing 48824, USA.
Arnoczky
Steven P
SP
Lavagnino
Michael
M
Tashman
Scott
S
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000473:pathology* / Q000648:ultrastructure; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D007593:Joint Instability / Q000473:pathology / Q000662:veterinary*; D013264:Stifle / Q000473:pathology*