In current-generation designs of total primary hip joint replacement. the prostheses are fabricated from alloys. The modulus of elasticity of the alloy is substantially higher than that of the surrounding bone. This discrepancy plays a role in a phenomenon known as stress shielding. https://www.roneverhart.com/Ryukyu-Kobujutsu-Buki-Jutsu-Vol-2-DVD-with-Kiyoshi-Yogi/