I am desperate for help. I had a knee placement in 2017 and was never able to bend the knee or walk due to scar tissue. I am having another knee placement but my recent patch testing showed a mild positive reaction to benzoyl peroxide which is used in bone cements. The surgeon I saw in Boston feels that this was the issue. Does anyone know if there are any bone cements that do not use benzoyl peroxide? It is used initiate the polymerization of the methylmethacrylate monomer. I am only 58 and have lost the last 3 years of my life.