Osteoarthritis is a painful and potentially crippling joint disease. OA is primarily a disease of the articular cartilage, and a single blunt impact has been suggested as a triggering factor in its development. In this study, the patellar cartilage of a rabbit was traumatized with a single blunt impact. The object of this experiment was to measure alterations in the mechanical properties of the cartilage as a result of this insult. The cartilage properties were measured via an indentation-relaxation test at various times to 12 months post—impact. We were able to measure a "softening" and increased permeability of the tissue in the short-term, but these material properties seemed to return to normal levels by 14 days to 3 months, depending on impact energy level. Fissuring of the articular surface was documented as a result of blunt trauma. Peak contact pressures in the joint (recorded with pressure sensitive film during impact) were coupled with a simple finite element model of the cartilage layer. The results of this model indicated that tensile stresses and strains caused the fissuring. Suture projects will involve the effects of exercise, and diagnosis with magnetic resonance imaging.