Staying Ahead of the Curve: The Case for Recovery Curves in Total Knee Arthroplasty.

Background: Sensor technology embedded within the total knee arthroplasty (TKA) implant has the potential to record data that can track recovery and provide diagnostic information. In this study, we introduce the concept of physical function recovery curve analytics, which are created from daily spatial-temporal gait metrics and step counts from a large cohort of TKA patients.

Methods: In our study population, 258 patients underwent a primary TKA with a smart implanted tibial extension between October 4, 2021, and July 15, 2022, by 33 surgeons.

A robotic emulator for the systematic exploration of transtibial biarticular prosthesis designs.

People with transtibial limb loss frequently experience suboptimal gait outcomes. This is partly attributable to the absence of the biarticular gastrocnemius muscle, which plays a unique role in walking. Although a recent surge of biarticular prostheses aims to restore gastrocnemius function, the broad design space and lack of consensus on optimal hardware and control strategies present scientific and engineering challenges.

Caveolae and Bin1 form ring-shaped platforms for T-tubule initiation.

Excitation-contraction coupling requires a highly specialized membrane structure, the triad, composed of a plasma membrane invagination, the T-tubule, surrounded by two sarcoplasmic reticulum terminal cisternae. Although the precise mechanisms governing T-tubule biogenesis and triad formation remain largely unknown, studies have shown that caveolae participate in T-tubule formation and mutations of several of their constituents induce muscle weakness and myopathies. Here, we demonstrate that, at the plasma membrane, Bin1 and caveolae composed of caveolin-3 assemble into ring-like structures from which emerge tubes enriched in the dihydropyridine receptor.

Design and Evaluation of a Knee Flexion Assistance Exoskeleton for People with Transtibial Amputation.

People with below-knee amputation walk with asymmetric gaits that over time can lead to further musculoskeletal disorders and decreased quality of life. While prosthesis technology is improving, prosthetic ankles may be fundamentally limited in their ability to restore healthy walking patterns because they do not assist the residual knee joint. The knee on the residual limb has muscular deficits due to the loss of the gastrocnemius, a biarticular muscle that crosses both the ankle and knee.

Evaluation of novel plantar pressure-based 3-dimensional printed accommodative insoles - A feasibility study.

Background: Custom insoles are commonly prescribed to patients with diabetes to redistribute plantar pressure and decrease the risk of ulceration. Advances in 3D printing have enabled the creation of 3D-printed personalized metamaterials whose properties are derived not only from the base material but also the lattice microstructures within the metamaterial. Insoles manufactured using personalized metamaterials have both patient-specific geometry and stiffnesses.

A novel workflow to fabricate a patient-specific 3D printed accommodative foot orthosis with personalized latticed metamaterial.

Patients with diabetes mellitus are at elevated risk for secondary complications that result in lower extremity amputations. Standard of care to prevent these complications involves prescribing custom accommodative insoles that use inefficient and outdated fabrication processes including milling and hand carving. A new thrust of custom 3D printed insoles has shown promise in producing corrective insoles but has not explored accommodative diabetic insoles.

Full body musculoskeletal model for simulations of gait in persons with transtibial amputation.

This paper describes the development, properties, and evaluation of a musculoskeletal model that reflects the anatomical and prosthetic properties of a transtibial amputee using OpenSim. Average passive prosthesis properties were used to develop CAD models of a socket, pylon, and foot to replace the lower leg. Additional degrees of freedom (DOF) were included in each joint of the prosthesis for potential use in a range of research areas, such as socket torque and socket pistoning.

Evaluation of a quasi-passive biarticular prosthesis to replicate gastrocnemius function in transtibial amputee gait.

Lower limb amputees experience gait impairments, in part due to limitations of prosthetic limbs and the lack of a functioning biarticular gastrocnemius (GAS) muscle. Energy storing prosthetic feet restore the function of the soleus, but not GAS. We propose a transtibial prosthesis that implements a spring mechanism to replicate the GAS.

Characterization of performance and disinfection resilience of nonwoven filter materials for use in 3D-printed N95 respirators.

The COVID-19 pandemic has caused a high demand for respiratory protection among health care workers in hospitals, especially surgical N95 filtering facepiece respirators (FFRs). To aid in alleviating that demand, a survey of commercially available filter media was conducted to determine whether any could serve as a substitute for an N95 FFR while held in a 3D-printed mask (Stopgap Surgical Face Mask from the NIH 3D Print Exchange). Fourteen filter media types and eight combinations were evaluated for filtration efficiency, breathing resistance (pressure drop), and liquid penetration.

A novel walking cane with haptic biofeedback reduces knee adduction moment in the osteoarthritic knee.

Knee osteoarthritis is a leading cause of ambulatory disability in adults. The most prescribed mobility aid, the walking cane, is often underloaded and therefore fails to reduce knee joint loading and provide symptomatic relief. For this study, a novel walking cane with haptic biofeedback was designed to improve cane loading and reduce the knee adduction moment (KAM).

[Drug management of behavioral disorders in people with developmental and intellectual disability].

Behavioral disorders in people with developmental and intellectual disability are frequent but their management is rarely taught. This article is to help primary physicians prescribe drug treatment. We will also discuss the key elements of two of the most commonly used classes of drugs, taking into account the patient's co-morbidities, contraindications and the main side effects.

Inactivation of Severe Acute Respiratory Coronavirus Virus 2 (SARS-CoV-2) and Diverse RNA and DNA Viruses on Three-Dimensionally Printed Surgical Mask Materials.

Background: Personal protective equipment (PPE) is a critical need during the coronavirus disease 2019 (COVID-19) pandemic. Alternative sources of surgical masks, including 3-dimensionally (3D) printed approaches that may be reused, are urgently needed to prevent PPE shortages. Few data exist identifying decontamination strategies to inactivate viral pathogens and retain 3D-printing material integrity.

Design and Development of a Quasi-Passive Transtibial Biarticular Prosthesis to Replicate Gastrocnemius Function in Walking.

Lower-limb amputees experience many gait impairments and limitations. Some of these impairments can be attributed to the lack of a functioning biarticular gastrocnemius (GAS) muscle. We propose a transtibial prosthesis that implements a quasi-passive spring mechanism to replicate GAS function.

Dynamics of triadin, a muscle-specific triad protein, within sarcoplasmic reticulum subdomains.

In skeletal muscle, proteins of the calcium release complex responsible for the excitation-contraction (EC) coupling are exclusively localized in specific reticulum-plasma membrane (ER-PM) contact points named triads. The CRC protein triadin (T95) is localized in the sarcoplasmic reticulum (SR) subdomain of triads where it forms large multimers. However, the mechanisms leading to the steady-state accumulation of T95 in these specific areas of SR are largely unknown.

Development of a Robotic Unloader Brace for Investigation of Conservative Treatment of Medial Knee Osteoarthritis.

Knee osteoarthritis (KOA) is a painful and debilitating condition that is associated with mechanical loading of the knee joint. Numerous conservative treatment strategies have been developed to delay time to total joint replacement. Unloader braces are commonly prescribed for medial uni-compartmental KOA, however their evidence of efficacy is inconclusive and limited by user compliance.

A Model-Based Method for Minimizing Reflected Motor Inertia in Off-board Actuation Systems: Applications in Exoskeleton Design.

The research and development of wearable robotic devices has been accelerated by off-board control and actuation systems. While off-board robotic actuation systems provide many benefits, the impedance at the robotic joint is often high. High joint impedance is undesirable for wearable devices like exoskeletons, as the user is unable to move their joint without actively controlled motion from the motors.

Deletion of the microtubule-associated protein 6 (MAP6) results in skeletal muscle dysfunction.

Background: The skeletal muscle fiber has a specific and precise intracellular organization which is at the basis of an efficient muscle contraction. Microtubules are long known to play a major role in the function and organization of many cells, but in skeletal muscle, the contribution of the microtubule cytoskeleton to the efficiency of contraction has only recently been studied. The microtubule network is dynamic and is regulated by many microtubule-associated proteins (MAPs).

3D Printed lattice microstructures to mimic soft biological materials.

Objective: Our group has developed a method for 3D printing mechanically-realistic soft tissue, as a building block towards developing anatomically realistic 3D-printed biomechanical testbed models.

Methods: A Polyjet 3D printer was used to print lattice microstructures, which were tested in compression to evaluate the elastic profile. Lattice properties including element diameter, element spacing (ES), element cross-sectional geometry, element arrangement, and lattice rotation were varied to determine their effect on the stress-strain curve.

A pediatric robotic thumb exoskeleton for at-home rehabilitation: the Isolated Orthosis for Thumb Actuation (IOTA).

In this paper, we present the design of a thumb exoskeleton for pediatric at-home rehabilitation. Pediatric disorders, such as cerebral palsy (CP) and stroke, can result in thumb in palm deformity greatly limiting hand function. This not only limits children's ability to perform activities of daily living but also limits important motor skill development.

Second metatarsal length is positively correlated with increased pressure and medial deviation of the second toe in a robotic cadaveric simulation of gait.

Background: The term `crossover second toe' has been used to describe a deformity of the second metatarsophalangeal joint (MTPJ) that includes a progressive migration of the second toe in a dorsal and medial direction. The long onset and complex anatomy of the deformity has led to uncertainty about its etiology and treatment. The purpose of this study was to investigate the relationship between second metatarsal length and second MTPJ plantar pressure and joint angles during gait.

A robotic cadaveric flatfoot analysis of stance phase.

The symptomatic flatfoot deformity (pes planus with peri-talar subluxation) can be a debilitating condition. Cadaveric flatfoot models have been employed to study the etiology of the deformity, as well as invasive and noninvasive surgical treatment strategies, by evaluating bone positions. Prior cadaveric flatfoot simulators, however, have not leveraged industrial robotic technologies, which provide several advantages as compared with the previously developed custom fabricated devices.

Foot bone kinematics as measured in a cadaveric robotic gait simulator.

The bony motion of the foot during the stance phase of gait is useful to further our understanding of joint function, disease etiology, injury prevention and surgical intervention. In this study, we used a 10-segment in vitro foot model with anatomical coordinate systems and a robotic gait simulator (RGS) to measure the kinematics of the tibia, talus, calcaneus, cuboid, navicular, medial cuneiform, first metatarsal, hallux, third metatarsal, and fifth metatarsal from six cadaveric feet. The RGS accurately reproduced in vivo vertical ground reaction force (5.