Concept and simulation of an alternative design for an orthopaedic shoulder implant

A Predictive Toxicokinetic Model for Nickel Leaching from Vascular Stents

In vitro testing methods offer valuable insights into the corrosion vulnerability of metal implants and enable prompt comparison between devices. However, they fall short in predicting the extent of leaching and the biodistribution of implant byproducts under in vivo conditions. Physiologically based toxicokinetic (PBTK) models are capable of quantitatively establishing such correlations and therefore provide a powerful tool in advancing nonclinical methods to test medical implants and assess patient exposure to implant debris. In this study, we present a multicompartment PBTK model and a simulation engine for toxicological risk assessment of vascular stents. The mathematical model consists of a detailed set of constitutive equations that describe the transfer of nickel ions from the device to peri-implant tissue and circulation and the nickel mass exchange between blood and the various tissues/organs and excreta. Model parameterization was performed using (1) in-house-produced data from immersion testing to compute the device-specific diffusion parameters and (2) full-scale animal in situ implantation studies to extract the mammalian-specific biokinetic functions that characterize the time-dependent biodistribution of the released ions. The PBTK model was put to the test using a simulation engine to estimate the concentration-time profiles, along with confidence intervals through probabilistic Monte Carlo, of nickel ions leaching from the implanted devices and determine if permissible exposure limits are exceeded. The model-derived output demonstrated prognostic conformity with reported experimental data, indicating that it may provide the basis for the broader use of modeling and simulation tools to guide the optimal design of implantable devices in compliance with exposure limits and other regulatory requirements.

A case report on a IV-degree thermal crush injury of right upper arm：The application of functional prosthesis implantation technology

Severe IV-degree thermal crush injury of limbs involved the subcutaneous fascia, muscle and bone, which may lead to amputation and has a great impact on the patient's quality of life. We can repair wounds with pedicle flaps or even free flaps, However, there are still huge challenges in bone defect of extremities and functional reconstruction. In recent years, with the development of functional prostheses, we have reconstructed limb functions in many patients helping them to complete their daily lives. We report a case where the right upper arm was injured by thermal crush, leading severe burns to the skin, fascia, muscle and bone. We applied a pedicled latissimus dorsi flap and a free anterolateral thigh flap to repair the wound, and realized the function of limb salvage and movement of the right upper arm by implanting 3D printed scapula, upper arm and elbow joint prostheses. This case illustrates that IV-degree burns involving bones have new technologies to repair and achieve mobility now.