Histopathological Changes in Knee Joint Components after Spinal Cord Injury in Rats

[Purpose] The purpose of this study was to examine the histopathological changes in knee joint components after spinal cord injury (SCI) in rats. [Subjects and Methods] Eighteen adult, nine-week-old female Wistar rats were used in this study. Nine experimental rats underwent a spinal cord transection at the level of Th8-9 and the other nine control rats were raised normally. The animals were assessed at 1, 2 and 4 weeks after surgery. Formalin fixed sections from knee joints were morphologically examined after hematoxylin and eosin staining. Alterations of knee joint components were evaluated at four regions: the synovial membrane within the posterior articular capsule region, the cartilage apposite the femur, the cartilage apposite the tibia, and the fat pad under the patellar ligament region. [Results] Dilatation and congestion of the microvasculature and lymphoid infiltration were observed in the synovial membrane in the SCI group. These findings are similar to those found in early osteoarthritis. The surface layer of the articular cartilage in the SCI group showed fibrous proliferation. [Conclusion] The histopathological changes appear not to be progressive and may be related to spasticity of the hindlimb or a disorder in the autonomic function.