In Vivo Skeletal Responses to Porous-Surfaced Implants Subjected to Small Induced Motions*

Bone ingrowth on the surface of endosseous implants. Part 1: Mathematical model

“…This phase can be enhanced by the presence of growth factors (Linkhart et al, 1996) and is also influenced by the mechanical state of the tissue. Actually, moderate mechanical stimulation of cells can enhance osseointegration (Rubin and McLeod, 1994) by promoting differentiation of osteogenic cells into osteoblasts and increasing the secretion of growth factors (Pavlin et al, 2000;Pavlin and Gluhak-Heinrich, 2001), but excessive levels of tensile or deviatoric stresses can also induce the formation of a not desirable fibrous tissue around the implant (Jones et al, 1995;Jasty et al, 1997). The global importance of this phase, sometimes referred to as osteoconduction, is crucial and has been highlighted in Davies (2003).…”

In vitro assessments of reverse glenoid stability using displacement gages are misleading — Recommendations for accurate measurements of interface micromotion

“…Although relative differences may be large when comparing micromotions from blocks of different densities, absolute values of micromotion remained very low, especially when compared to previously reported values and to the limits needed to create loosening. In any case, caution should be exercised when equating micromotion measured on Sawbones with the physiological limits on bone ingrowth (Cameron et al, 1973, Ducheyne et al, 1977, Jasty et al, 1997a, Jasty et al, 1997b, Pilliar et al, 1986.…”

“…Nevertheless, the rate of problems remains high, in part because of glenoid component loosening (Gerber et al, 2009, Mole andFavard, 2007). Micromotion from 28 to 150 micrometers (µm) has been shown to inhibit bone ingrowth and lead to an unstable fibrous tissue layer between a metallic implant and the host bone (Cameron et al, 1973, Ducheyne et al, 1977, Jasty et al, 1997a, Jasty et al, 1997b, Pilliar et al, 1986. Therefore, minimizing micromotion at the time of initial fixation should lead to better ingrowth of bone and a more stable implant.…”

Biphasic constitutive laws for biological interface evolution

“…Experimental studies have shown that the fibrous tissue formation is related to the micromotions at the bone-implant interface (Brunski et al 1979;Farron et al 1995;Jasty et al 1997;Levy et al 1996;Søballe et al 1992a, b). The mechanical contact between the bone and the implant is complex but it can be decomposed into two major types of contacts.…”

“…In order to determine these parameters, an axisymmetric finite element (FE) model was developed with the same geometry and loading conditions as the experiment of Jasty et al (1997). The three parameters are varied until we obtained the same thickness of fibrous tissue as Jasty et al for micromotions of 20 lm and 150 lm after 3 weeks of evolution.…”