The importance of loading frequency, rate and vibration for enhancing bone adaptation and implant osseointegration

Abstract

Mechanical loading is one of the key factors that influence bone mass and the osseointegration of bone-anchored implants. From a clinical point of view, mechanical stimulation may be used to enhance bone strength and implant osseointegration. Among the many loading parameters that influence the response to mechanical loading, the effects of loading frequency and rate have been investigated in many studies. In this paper the most relevant animal studies that have addressed the effect of loading frequency, rate, and vibration on either bone adaptation or implant osseointegration are systematically reviewed. Apparently contradictory results are discussed and interpreted within the context of mechanotransduction and mechanoregulation of bone. A combined experimental and computational approach is suggested to address some of the remaining research questions.

Effects of whole-body vibration on plasma sclerostin level in healthy women

“…Sclerostin is expressed almost exclusively in osteocytes, and these osteocytes are able to detect mechanical strain (9). Osteocytes are stimulated by mechanical deformation of bone (10). The main mechanical factors determining the impact of mechanical loading on bones are strain (strain magnitude, strain rate), stress, and the frequency or the number of loading cycles (11)(12)(13)(14)(15).…”

Development of Composite Scaffolds for Load Bearing Segmental Bone Defects

“…It is known that -TCP degrades at a much faster rate than HAp. However, faster degradation often equates to a higher level of Ca 2+ being released, and any localized Ca 2+ released higher than 10 mMol [89] is detrimental, including being cytotoxic at the site. It is also known that the sintering process makes CaP ceramics stronger, but compromises the surface bioactivity of the scaffold due to the overall increase in crystal size and crystallinity [38].…”

Mechanotransduction and Osteogenesis

“…Since various local gradients of deformation are created, more bone cells are incited to produce bone. In other words, there are more sites of osteogenesis; therefore, mechanical loads with lower strain at higher frequencies applied to bone will incite significant bone formation Fritton et al, 2000;Hsieh & Turner, 2001;Jacobs et al, 1998;Rubin et al, 2001;Torcasio et al, 2008;Warden & Turner, 2004;). …”

“…In conclusion, the role of mechanostat is to avoid mechanical deformations above 3000 μstrain, which may cause bone fracture. Further, in addition to Frost's mechanostat model, it was realized that mechanostat can sense other physical parameters not only relative deformation: frequency, number of cycles resting periods, relative deformation distribution and local gradients of relative deformation (Torcasio et al, 2008). Relative deformation, frequency, number of cycles and resting periods are the unique variables that can be controlled in mechanical assays.…”