In vivo evaluation of defined polished titanium surfaces to prevent soft tissue adhesion

Abstract

Soft tissue-implant adhesion is often required for implant integration into the body; however, in some situations, the tissue is required to glide freely over an implant. In the case of distal radius fracture treatment, current literature describes how titanium and its alloys tend to lead to more intra-tendon inflammatory reactions compared with stainless steel. This leads to tendon-implant adhesion and damage possibly causing limited palmar flexion and even tendon rupture. The goal of this study was to analyze the effect of different surface polishings of titanium and titanium molybdenum implants on soft tissue reactions in vivo, with the aim to prevent direct soft tissue adhesion. Using a nonfracture model, to allow for study of the soft-tissue-implant surface interactions only, six surface variants of the same plate design were implanted onto the tibia of 24 New Zealand white rabbits and left in situ for 12 weeks. Results indicate that paste polished commercially pure titanium and titanium molybdenum alloy had the least soft tissue adhesion, with the concomitant development of a soft tissue capsule. Surface topography did not appear influence the thickness of the connective tissue surrounding the plate. Therefore, suitable surface polishing could be applied to plates for clinical use, where free gliding of tissues is required.

Influence of steel implant surface microtopography on soft and hard tissue integration

“…The advantages of titanium include decreased implant stiffness and increased biocompatibility . However, titanium has been implicated in tendon irritation and adhesions when used in the hand and wrist . It is hypothesized that the enhanced intra‐tendon inflammation observed for cpTi implants and the formation of a fibrous capsule containing a liquid filled void is mainly attributable to the differences in microtopography between EPSS and cpTi implants.…”

“…Ramaglia and colleagues also show that micro‐rough titanium surfaces supported increased collagen and fibronectin production, hence conditioning the surface prior to healing . In a preclinical rabbit model, it has been shown using the same material (titanium or titanium alloy) with varying microtopographies that soft tissue adhesion can be differentially controlled with varying surface roughness . These findings are also supported by additional in vitro evidence, whereby in a series of studies, Meredith and colleagues demonstrate that in the case of steel, titanium and titanium alloy microtopography, and not chemistry, was solely responsible for fibroblast proliferation.…”

“…Current metal internal fixators are fabricated predominantly from electropolished stainless steel (EPSS) and commercially pure titanium (cpTi). In preclinical models fibrotic tendon adhesions appear to be more prevalent with cpTi implants compared to EPSS . Sinicropi and colleagues demonstrated in an osteotomy model created in the distal radius of beagle dogs that after 4 months implantation, 100% of the EPSS implants allowed for free‐gliding of tendons.…”

Advances in Biomaterials and Surface Technologies

“…9 Translation of in vitro results to in vivo preclinical models has been observed: smoothening surfaces avoids bone integration, reduces torque for removal of screws and nails, and facilitates removal. [6][7][8] For metal internal fracture fixation implants, clinically used surface microtopography does not seem to influence implant susceptibility to infection. [10][11][12] Plates in anatomical areas, such as the hand, shoulder, and craniomaxillofacial regions should minimize adherence of tissue (nerves, muscles, and bone) to allow for free gliding.…”

“…Implant surface microtopography is a major determinant of implant-bone tissue interaction. [6][7][8][9] In vitro studies showed that polishing reduces expression and function of genes specific for osteoblast differentiation and maturation, compared with standard micro-rough counterparts. Surface polishing seems to target cell events for terminal differentiation: osteocalcin mRNA is markedly reduced for polished Ti and Ti-alloy samples.…”