Fatigue properties and stem subsidence in wire coil reinforced PMMA bone cement: a preliminary in vitro study.

The longevity of the cemented total hip joint replacement depends on the integrity of the cement fixation with respect to the interfaces of the metal stem and bone, and stress/strain transmission and its distribution. A simple stainless steel wire coil was placed around a tapered stem in a simulated cement mantle to counteract radial- and hoop-stress and dynamic compression-compression tests were performed. The results showed that the wire coil reinforced cement group had a higher fatigue (30%) and strength (35%) up to 10(5) loading cycles. The amount of stem subsidence during fatigue tests of the wire reinforced group was significantly reduced (2.5 times) compared with the control group.