Biomechanical Characterisation of Bone-anchored Implant Systems for Amputation Limb Prostheses: A Systematic Review

Abstract

Bone-anchored limb prostheses allow for the direct transfer of external loads from the prosthesis to the skeleton, eliminating the need for a socket and the associated problems of poor fit, discomfort, and limited range of movement. A percutaneous implant system for direct skeletal attachment of an external limb must provide a long-term, mechanically stable interface to the bone, along with an infection barrier to the external environment. In addition, the mechanical integrity of the implant system and bone must be preserved despite constant stresses induced by the limb prosthesis. Three different percutaneous implant systems for direct skeletal attachment of external limb prostheses are currently clinically available and a few others are under investigation in human subjects. These systems employ different strategies and have undergone design changes with a view to fulfilling the aforementioned requirements. This review summarises such strategies and design changes, providing an overview of the biomechanical characteristics of current percutaneous implant systems for direct skeletal attachment of amputation limb prostheses.

Orthopaedic osseointegration: Implantology and future directions

“…The bulk properties of OI implants, such as strength, toughness, and elastic modulus, are determined by the chemical composition and structure of the materials used to manufacture the implant. Metals and metal alloys, most commonly commercially pure titanium CP1‐Grade 4 and titanium Grade 5‐ titanium 6Al‐4V alloy, are primarily used to manufacture OI implants due to their strength and toughness . Titanium has a high specific strength (strength per density) and high corrosion resistance (due to the formation of a passive titanium oxide layer) compared to other metals.…”

Proximal Bone Remodeling in Lower Limb Amputees Reconstructed With an Osseointegrated Prosthesis

“…Traditionally, lower limb amputees undergo rehabilitation with a TSP to restore some degree of daily function and mobility. This solution subjects the bony residuum to a unique mechanical environment where the intensity and frequency of loading differs from normal gait, as weight and impact is instead distributed through multiple connectors, liners, and bandages in a manner that differs dramatically from the natural loading environment . As a result, lower limb amputees commonly have lower BMD levels when compared with the general population, as expected in accordance with Wolff's Law .…”

“…As osseointegrated prostheses become a more popular clinical option for amputees, understanding any longitudinal change in the bone integrity of the proximal femur becomes an important consideration when evaluating the risk of fracture in this region for these patients. Compared with a TSP, osseointegrated implants result in better limb biomechanics as the implant is skeletally attached along the anatomical axis of the residual limb . Studies investigating the effects of osseointegrated implants on the adjacent bone have demonstrated immediate changes in the bone architecture .…”

2019 ABME Paper Awards

“…Each year, the top papers in Annals of Biomedical Engineering (ABME) are selected for editorial awards that are presented at the annual Biomedical Engineering Society (BMES) meeting. At the 2019 BMES Annual Meeting, a total of five awards were presented: one award for the most citations, 1 one award for the most downloads, 9 and three editor's choice awards. 5,6,8 These papers were selected from a total of 182 papers published in 2018.…”

“…Thesleff et al reviewed all currently available boneanchored limb prostheses along with their biomechanical characteristics. 9 The percutaneous implant systems directly attach to the bone of an external limb, and therefore must be mechanically stable and withstand constant stresses from the limb over a long period of time, along with providing an infection barrier to the environment.…”