Biocompatibility Analysis of the Silver-Coated Microporous Titanium Implants Manufactured with 3D-Printing Technology.

3D-printed microporous titanium scaffolds enjoy good biointegration with the residuum's soft and bone tissues, and they promote excellent biomechanical properties in attached prostheses. Implant-associated infection, however, remains a major clinical challenge. Silver-based implant coatings can potentially reduce bacterial growth and inhibit biofilm formation, thereby reducing the risk of periprosthetic infections.

Transforming the Anthropomorphic Passive Free-Flow Foot Prosthesis Into a Powered Foot Prosthesis With Intuitive Control and Sensation (Bionic FFF).

Introduction: Approximately 89% of all service members with amputations do not return to duty. Restoring intuitive neural control with somatosensory sensation is a key to improving the safety and efficacy of prosthetic locomotion. However, natural somatosensory feedback from lower-limb prostheses has not yet been incorporated into any commercial prostheses.

Modeling of the Effect of Subperiosteal Hydrostatic Pressure Conductivity between Joints on Decreasing Contact Loads on Cartilage and of the Effect of Myofascial Relief in Treating Trigger Points: The Floating Skeleton Theory.

Chronic overloading of the cartilage can lead to its irreversible destruction, as observed in people with osteoarthritis. The floating skeleton model previously introduced postulates that overloading begins and progresses when a joint is isolated from the hydrostatical connection with other joints. Such a connection occurs via the interstitial fluid in subperiosteal space and allows for pressure transmission between synovial capsules modulating intra-articular pressure.

The Moment Criterion of Anthropomorphicity of Prosthetic Feet as a Potential Predictor of Their Functionality for Transtibial Amputees.

The purpose of this paper is to discuss a new quantitative mechanical parameter of prosthetic feet called the Index of Anthropomorphicity (), which has the potential to be adopted as an objective predictor of their functionality. The objectives are to present the research findings supporting the introduction of and unify previous results into a coherent theory. The is founded on the moment criterion of the anthropomorphicity of prosthetic feet.

Electrical Stimulation of Distal Tibial Nerve During Stance Phase of Walking May Reverse Effects of Unilateral Paw Pad Anesthesia in the Cat.

Cutaneous feedback from feet is involved in regulation of muscle activity during locomotion, and the lack of this feedback results in motor deficits. We tested the hypothesis that locomotor changes caused by local unilateral anesthesia of paw pads in the cat could be reduced/reversed by electrical stimulation of cutaneous and proprioceptive afferents in the distal tibial nerve during stance. Several split-belt conditions were investigated in four adult female cats.

Temporary Botulinum Immobilization of Residuum Muscles for Facilitation of the Initial Ingrowth of Skin to the Porous in the Technology of Direct Skeletal Attachment: Large Animal Model.

Enhancing the technology of bone-anchored limb prosthetics, we present a modified porcine model for developing an infection-free integration between the skin and a percutaneous bone implant. The deeply porous Skin and Bone Integrated Pylon (SBIP) presented an infection-free skin-implant interface both after implantation into the dorsum and after implantation into the residuum after below-knee amputation. However, deep ingrowth of skin into the porous cladding of the SBIP was achieved better in the dorsal procedure, while implantation to the residuum sometimes developed a stoma, probably due to the high mobility of the skin and soft tissues in the pig's thigh.

New Training System Based on the Discovery of Subperiosteal Transmission of Pressures Between Joint Capsules.

Background: A new training and rehabilitation methodology called Sanomechanics® is presented based on a recent discovery of the anatomical system called Floating Skeleton System (FSS) responsible for redistributing contact pressures in the joint capsules and thus minimizing the loads on joint cartilages.

Materials And Methods: The main idea behind the Sanomechanics® methodology (SMM) is that when this system of subperiosteal pressure transmission is disrupted, the overloading of cartilages may occur leading to trauma, osteoarthritis and other related pathologies. Conversely, if functioning of the FSS is adequately restored and continuously maintained, the pathological developments can be effectively stopped.

Loading Effect of Prosthetic Feet's Anthropomorphicity on Transtibial Osseointegrated Implant.

Introduction: Osseointegrated implants for direct skeletal attachment of transtibial prosthesis carry risks that are yet to be fully resolved, such as early loosening, mechanical failure of percutaneous and medullar parts of implant, periprosthetic issues, and infections. Underloading could lead to early loosening and infection. Overloading might compromise the bone-implant interface.

Recent Progress in Animal Studies of the Skin- and Bone-integrated Pylon With Deep Porosity for Bone-Anchored Limb Prosthetics With and Without Neural Interface.

Introduction: The three major unresolved problems in bone-anchored limb prosthetics are stable, infection-free integration of skin with a percutaneous bone implant, robust skeletal fixation between the implant and host bone, and a secure interface of sensory nerves and muscles with a prosthesis for the intuitive bidirectional prosthetic control. Here we review results of our completed work and report on recent progress.

Materials And Methods: Eight female adult cats received skin- and bone-integrated pylon (SBIP) and eight male adult cats received SBIP-peripheral neural interface (PNI) pylon into the right distal tibia.

Protecting the skin-implant interface with transcutaneous silver-coated skin-and-bone-integrated pylon in pig and rabbit dorsum models.

Implant-associated soft tissue infections at the skin-implant interface represent the most frequent complications in reconstructive surgery and lead to implant failures and revisions. Titanium implants with deep porosity, called skin-and-bone-integrated-pylons (SBIP), allow for skin ingrowth in the morphologically natural direction, thus restoring a reliable dermal barrier and reducing the risk of infection. Silver coating of the SBIP implant surface using physical vapor deposition technique offers the possibility of preventing biofilm formation and exerting a direct antimicrobial effect during the wound healing phase.

Automated characterization of anthropomorphicity of prosthetic feet fitted to bone-anchored transtibial prosthesis.

Objective: This study describes differentiating prosthetic feet designs fitted to bone-anchored transtibial prostheses based on an automated characterization of ankle stiffness profile relying on direct loading measurements. The objectives were (A) to present a process characterizing stiffness using innovative macro, meso and micro analyses, (B) to present stiffness profiles for feet with and without anthropomorphic designs, where anthropomorphicity is defined as a similarity of the moment-angle dependency in prosthetic and in the anatomical ankle, (C) to determine sensitivity of characterization.

Methods: Three participants walked consecutively with two instrumented bone-anchored prostheses including their own prosthetic feet and Free-Flow foot meeting the anthropomorphicity criterion by design.

Distraction Implantation. A New Technique in Total Joint Arthroplasty and Direct Skeletal Attachment.

Background: Using the marrow canal of a tubular bone as a holding compartment for implant stems has been the paradigm in total joint arthroplasty for more than a century, and for direct skeletal attachment of limb prostheses for about forty years. Both interventions rely on the osteogenesis in the inner walls of the marrow canal in a direction radially inwards. It so remains despite the frequent aseptic loosening of the implant stems caused by the resorption of the marrow canal's inner walls which increases the canal's diameter and reduces its capacity to hold the implant.

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

Ongoing animal preclinical studies on transcutaneous bone-anchored prostheses have aimed to improve biomechanics of prosthetic locomotion in people with limb loss. It is much less common to translate successful developments in human biomechanics and prosthetic research to veterinary medicine to treat animals with limb loss. Current standard of care in veterinary medicine is amputation of the whole limb if a distal segment cannot be salvaged.

Evaluation of the temporary effect of physical vapor deposition silver coating on resistance to infection in transdermal skin and bone integrated pylon with deep porosity.

Periprosthetic infection via skin-implant interface is a leading cause of failures and revisions in direct skeletal attachment of limb prostheses. Implants with deep porosity fabricated with skin and bone integrated pylons (SBIP) technology allow for skin ingrowth through the implant's structure creating natural barrier against infection. However, until the skin cells remodel in all pores of the implant, additional care is required to prevent from entering bacteria to the still nonoccupied pores.

Subperiosteal transmission of intra-articular pressure between articulated and stationary joints.

Hydrostatic pressures can be transmitted between synovial capsules. In each of ten rabbits, we simultaneously measured pressure in two joints, one of which was passively ranged, and the other of which was kept stationary. The intra-articular pressure inside the stationary joint changed every time its companion joint was ranged.

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

Background: Direct skeletal attachment of limb prostheses is associated with high rate of transcutaneous infection and loosening of the fixture in the medullary canal prompting for careful assessment of various means for enhancing the skin-device and bone-device interface. The skin and bone integrated pylon system constitutes a technological platform for different modifications being evaluated previously.

Objectives: The current study assessed the combination of nano-treatment skin and bone integrated pylon with its pre-seeding with dermal fibroblasts.

An animal model to evaluate skin-implant-bone integration and gait with a prosthesis directly attached to the residual limb.

Background: Despite the number of advantages of bone-anchored prostheses, their use in patients is limited due to the lack of complete skin-implant integration. The objective of the present study was to develop an animal model that would permit both detailed investigations of gait with a bone-anchored limb prosthesis and histological analysis of the skin-implant-bone interface after physiological loading of the implant during standing and walking.

Methods: Full-body mechanics of walking in two cats were recorded and analyzed before and after implantation of a percutaneous porous titanium pylon into the right tibia and attachment of a prosthesis.

Two-stage implantation of the skin- and bone-integrated pylon seeded with autologous fibroblasts induced into osteoblast differentiation for direct skeletal attachment of limb prostheses.

Angio- and osteogenesis following the two-stage (TS) implantation of the skin- and bone-integrated pylon seeded with autologous fibroblasts was evaluated. Two consecutive animal substudies were undertaken: intramedullary subcutaneous implantation (15 rabbits) and a TS transcutaneous implantation (12 rabbits). We observed enhanced osseointegrative properties of the intramedullary porous component seeded with fibroblasts induced into osteoblast differentiation, as compared to the untreated porous titanium pylon.

New method of fixation of in-bone implanted prosthesis.

This article presents results on the effectiveness of a new version of the titanium porous composite skin and bone integrated pylon (SBIP). The SBIP is designed for direct skeletal attachment of limb prostheses and was evaluated in a preclinical study with three rabbits. In accordance with the study protocol, a new version of the pylon (SBIP-3) was implanted into the hind leg residuum of three rabbits.

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

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 μm and Large, 100-160 μm), 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 seven groups.

On the way to total integration of prosthetic pylon with residuum.

Two decades after introducing threaded titanium dental implants, Dr. Per-Ingvar Brånemark used a similar technique in the 1980s to pioneer the direct skeletal attachment (DSA) of limb prostheses. He and his colleagues used convincing clinical experience to overcome the skepticism of their peers, affording a new dimension of prosthetic rehabilitation to almost 100 individuals with amputation.