Inducing residual stress in bone using abrasive air-jet surface treatment

Based on past research, the growth and repair of bone is a function of physical activity (i.e. stresses) and bone chemistry. As such, the rate of recovery of an individual that has undergone total joint arthroplasty could be influenced by the introduction of changes in bone chemistry and "apparent" stress state in the bone that results from the surgical procedures and/or treatments. This preliminary study explored the opportunity for introducing residual stresses in hard tissues using an air-jet surface treatment. Cortical bone was obtained from bovine femurs and treated with an abrasive jet process. The radius of curvature of the bone specimens was estimated before and after treatment and used in estimating the magnitude of surface residual stress. An SEM analysis was also performed to examine structural changes in the bone caused by the surface treatment. Results showed that it is possible to impart residual stress within bone using an air-jet surface treatment. The magnitude of surface residual stress was 16 +/- 0.8 MPa. Residual stresses appeared to result from a combination of near-surface deformation and embedded particles.