Pathologic changes in grossly normal menisci in dogs with rupture of the cranial cruciate ligament

Objective-To determine whether histopathologic changes are detectable in grossly normal medial menisci from dogs with rupture of the cranial cruciate ligament (CCL). Design-Case series. Sample Population-40 medial menisci from dogs with rupture of the CCL and 20 medial menisci from control dogs without stifle joint disease. Procedure-Data evaluated included age, duration of clinical signs, and whether rupture of the CCL was complete or incomplete. Three groups (n = 20/group) were also compared on the basis of 5 histologic criteria; group-1 menisci appeared grossly normal and were obtained from dogs with naturally occurring rupture of the CCL, group-2 menisci were grossly abnormal and were also obtained from dogs with naturally occurring CCL ruptures, and group-3 menisci were collected at postmortem from dogs without stifle joint disease that were of similar age and weight as dogs in groups 1 and 2. Results-Group-2 menisci were significantly different from group-1 and -3 menisci in all histologic criteria. Group-1 menisci were significantly different from control menisci in only 1 of the 5 histologic criteria (cartilage differentiation). Dogs that were greater than or equal to 3 years old had significantly more surface cellularity than did dogs that were < 3 years old. A significant difference was not detected between groups 1 and 2 with regard to completeness of rupture. Conclusions and Clinical Relevance-Histologic changes in meniscal cartilage correlate with gross appearance of the cartilage at time of surgery for rupture of the CCL. On the basis of minimal histologic changes, routine removal of grossly normal menisci does not appear to be warranted.