The effects of dynamic loading on intracalcaneal wood implants and on the tissues surrounding them

Abstract

The dorsal parts of the calcanei of rabbits were resected and replaced with similarly-shaped implants made of ash wood. In each case the Achilles tendon was reinserted into the projecting part of the implant so as to subject the latter to the dynamic loads generated by use of the limb. The implants were removed from some of the animals after 5 weeks and from the others after 14 weeks. They were evaluated by preparing undecalcified microtome sections and ground sections which were examined by light microscopy and microradiography. Some of the animals underwent vital staining so as to produce polychromatic sequential labelling of the calcaneal specimens. In the area of insertion of the Achilles tendon soft tissue grew into the larger pores of the wood and, in some cases, differentiated into cartilage. Every implant remained stably anchored in the calcaneus. In every animal the intracalcaneal part of the implant became surrounded by new bone which was in direct contact with the surface of the implant and which also formed in the pores of the wood, even all rabbits loaded the operated foot. The formation of new bone in and around the implants demonstrates the basic feasibility of using ash wood as an isoelastic implant material in bone.

Juniper wood as a possible implant material

“…Implantation into soft tissue indicated the importance of removing exudates for avoiding a foreign body response 45. A further study by the same authors,46 in which the dorsal location of the calcanei was replaced with cylindrically machined ash implants, illustrated good bone contact. Those results are in agreement with the findings in this article.…”

“…The role of piezoelectricity in wood is an important factor that could have promoted bone attachment into the small pores in the wood structure. The implant used in this study was predominantly subjected to shear stresses, compared to bending in the case of the implant placed in the calcaneous by Kristen et al46 This factor could have accentuated the piezoelectric response to provide the integration observed.…”

Preparation and in vitro characterization of biomorphic silk fibroin scaffolds for bone tissue engineering

“…The special structures not only facilitated the transport of nutrients and oxygen in the early period after implantation, but also effectively promoted osseointegration . An early observation on bone repair with wood implants verified that the unique pore structure of wood could promote the formation of new bone tissue . However, the direct application of wood as implants in body involves some potential safety issues such as soluble hazardous chemical compounds, immunogenicity, parasites, and bacteria.…”

The effect of heat treatment of wood on osteoconductivity

“…Types of wood used in studies include ash wood, birch, beech and juniper [17][18][19][20][21]. The pre-implantation treatment methods (pretreatments) used were a simple sterilization with alcohol (ethanol), boiling in water, and carbonizing.…”