Effects of pore size, implantation time, and nano‐surface properties on rat skin ingrowth into percutaneous porous titanium implants

Abstract

The main problem of percutaneous osseointegrated implants is poor skin-implant integration, which may cause infection. This study investigated the effects of pore size (Small, 40–100 microns and Large, 100–160 microns), nanotubular surface treatment (Nano), and duration of implantation (3 and 6 weeks) on skin ingrowth into porous titanium. Each implant type was percutaneously inserted in the back of 35 rats randomly assigned to 7 groups. Implant extrusion rate was measured weekly and skin ingrowth into implants was determined histologically after harvesting implants. It was found that all 3 types of implants demonstrated skin tissue ingrowth of over 30% (at week 3) and 50% (at weeks 4–6) of total implant porous area under the skin; longer implantation resulted in greater skin ingrowth (p<0.05). Only one case of infection was observed (infection rate 2.9%). Small and Nano groups showed the same implant extrusion rate which was lower than the Large group rate (0.06±0.01 vs. 0.16 ± 0.02 cm/week; p<0.05). Ingrowth area was comparable in the Small, Large and Nano implants. However, qualitatively, the Nano implants showed greatest cellular inhabitation within first three weeks. We concluded that percutaneous porous titanium implants allow for skin integration with the potential for a safe seal.

Kinetics of individual limbs during level and slope walking with a unilateral transtibial bone-anchored prosthesis in the cat

“…The SBIP material specification has a uniquely selected combination of four critical parameters: particle size, pore size, porosity and volume fraction (Pitkin and Raykhtsaum, 2012). This allows for deep ingrowth of the hosting tissues of bone and skin in combination with implant durability and resistance to fatigue (Farrell et al, 2014a,b; Pitkin et al, 2009). …”

“…For example, ongoing animal studies on transcutaneous porous titanium bone implants (Farrell et al, 2014a,b; Fitzpatrick et al, 2011; Pitkin et al, 2009; Shelton et al, 2011) have aimed to reduce skin infection in individuals with bone-anchored lower limb prostheses (Branemark et al, 2014; Drygas et al, 2008; Tillander et al, 2010; Tsikandylakis et al, 2014), and ultimately to improve biomechanics of prosthetic locomotion. It is much less common, however, to translate successful developments in human biomechanics, orthopedic and prosthetic research to veterinary medicine to treat animals with limb loss.…”

Application of the skin and bone integrated pylon with titanium oxide nanotubes and seeded with dermal fibroblasts

“…Several studies demonstrated promising results relating to cellular interactions with the nanotubular implant's surface, as compared to the smooth surface [7 9]. Positive effect of nano treatment on the bone device interface was confirmed in [3, 10 16].…”

“…In the work of Ruckh et al it was demonstrated that nanotube arrays on the implant surface significantly enhance osteoblast cell adhesion, proliferation and differentiation [17]. Less reports while also with positive results are known for the effect of nano treatment on the interface of a device with the skin [18, 19]. …”

Preventing infection of osseointegrated transcutaneous implants: Incorporation of silver into preconditioned fibronectin-functionalized hydroxyapatite coatings suppresses Staphylococcus aureus colonization while promoting viable fibroblast growth in vitro

“…27 This is important because it is planned that porous titanium will be employed as the underlying substrate to manufacture transcutaneous implants for clinical use as it promotes soft tissue ingrowth. 1,28,29 Other more commonly commercially available methods such as plasma spraying are not able to do this. Although fibroblast viability has been assessed for hydroxyapatite and silver (HAAg) coatings produced by other methods, it has not been previously reported for this method of electrochemical deposition.…”