Elevation of immunoglobulin deposition in the synovial membrane of dogs with cranial cruciate ligament rupture.

Synovial membrane biopsies were collected from 32 dogs with spontaneous cranial cruciate ligament rupture and seven control dogs. The subclasses of immunoglobulins in the synovial membrane of both the diseased and control dogs were examined with immunohistochemistry in combination with image analysis. IgG deposition was four-fold higher and IgM was eight-fold higher in dogs with spontaneous cranial crucial ligament (CrCL) rupture. These findings support the theory that there is an immune component to the inflammation associated with canine CrCL rupture. Further investigation is required to determine if these immune or inflammatory responses in CrCL rupture joints are the primary factor in ligament rupture or if they develop secondary to ligament rupture and instability.