Influence of the use of an adhesive connection on the joint strength of modular hip endoprostheses.

Introduction: Modular hip implants enables a more precise adaptation of the prosthesis to the patient's anatomy. However, they also carry the risk of increased revision rates due to micromotion at the taper junction. In order to minimize this risk, one potential solution is to establish an adhesive bond between the metal taper junctions.

Effect of tibiofemoral alignment on simulated knee contact forces during gait in mechanically and kinematically aligned total knee arthroplasty patients.

The goal of the study was to apply a musculoskeletal knee model that considers individual tibiofemoral alignment (TFA) and to investigate its effect on knee contact force (KCF) during gait in mechanically (MA) and kinematically aligned (KA) total knee arthroplasty (TKA) patients. Total, medial, and lateral KCF was estimated from pre- and postoperative gait data of TKA patients (MA: n = 26, KA: n = 22). Preoperative KCF was compared between the generic and the adapted model using t-tests and statistical parametric mapping (SPM).

Investigation of adaptive muscle synergy modulated motor responses to grasping perturbations.

This study investigated how muscle synergies adapt in response to unexpected changes in object weight during lifting tasks. The aim was to discover which motor control strategies individuals use to maintain their grasping performance. Muscle synergies were extracted from the muscle activity of fifteen healthy participants who lifted objects of identical appearance but varying weights in a randomized order, which introduced artificial perturbations.

Early monitoring of inlay wear after total knee arthroplasty on plain radiographs using model-based wear measurement.

Wear of the ultra-high molecular-weight polyethylene (UHMWPE) component in total knee arthroplasty contributes to implant failure. It is often detected late, when patients experience pain or instability. Early monitoring could enable timely intervention, preventing implant failure and joint degeneration.

[Implant anchorage: In vivo and in vitro analyses : Clusters for implant anchorage and safety].

Aseptic implant loosening is the primary cause of revisions in arthroplasty. Various in vitro and in vivo methods are available for assessing implant fixation and stability. The aim of the Musculoskeletal Biomechanics Research Network (MSB-NET) is to continuously improve or develop these methods.

Does glenoid inclination affect the anterior stability of reverse total shoulder arthroplasty? A biomechanical study.

Purpose: The anterior stability of reverse total shoulder arthroplasty is affected by multiple factors. However, the effect of glenosphere inclination on stability has rarely been investigated, which is what this study aims to look into.

Methods: Reverse shoulder arthroplasty was performed on 15 cadaveric human shoulders.

Very early migration of a calcar-guided short stem: a randomized study of early mobilization and the influence of a calcium phosphate coating with 60 patients.

This study analyzed the migration of a calcar-guided short stem to determine the course of very early migration, as well as evaluated the effect of an additional calcium phosphate (CP) coating on a titanium plasma spray (TPS) coating, which has not been analyzed previously. Sixty patients were enrolled in this study and were treated with the A2 calcar-guided short stem. The implant coating was randomized with either the TPS or an additional CP coating, and radiostereometric analysis was performed with the baseline measurement before initial weight-bearing, along with follow-up examinations at 1 week, 6 weeks, 3 months, and 6 months.

Radiopacity Enhancements in Polymeric Implant Biomaterials: A Comprehensive Literature Review.

Polymers as biomaterials possess favorable properties, which include corrosion resistance, light weight, biocompatibility, ease of processing, low cost, and an ability to be easily tailored to meet specific applications. However, their inherent low X-ray attenuation, resulting from the low atomic numbers of their constituent elements, i.e.

What do users and their aiding professionals want from future devices in upper limb prosthetics? A focus group study.

Background: High rejection rates of upper limb prosthetics indicate that current prosthetic devices only partially meet user demands. This study therefore investigated the benefits and challenges with current prostheses, associated services and potential areas for improvement from the perspective of upper limb prosthesis users and various professionals working in the field of upper limb and hand prosthetics.

Methods And Findings: Seven different focus group discussions were conducted with 32 participants.

Contribution of various forefoot areas to push-off peak at different speeds and slopes during walking.

Background: Push-off during the terminal stance phase has a major impact on forward progression during walking. During this phase, the ground reaction force is applied to a small area under the forefoot. A better understanding of how single forefoot areas contribute to push-off peak in healthy subjects is needed to develop biomimetic orthopedic devices for forefoot amputees.

Comparison of conventional socket attachment and bone-anchored prosthesis for persons living with transfemoral amputation - mobility and quality of life.

Background: For patients with transfemoral amputation experiencing issues with their sockets, bone-anchored prosthesis systems are an alternative and sometimes the only way to be mobile and independent. The present cross-sectional study aimed to investigate the gait performance and quality of life of a group of patients treated with bone-anchored systems compared to those of participants treated with a conventional socket-suspended prosthesis.

Methods: A total of 17 participants with a socket-suspended and 20 with a bone-anchored prosthesis were included.

The development and evaluation of an in-vitro shoulder simulator with active muscle simulation.

The purpose of the present study was to develop a novel active in-vitro shoulder simulator to emulate all forms of planar and non-planar glenohumeral motions with active muscle simulation on cadaver specimens or shoulder models and to critically evaluate its performance. A physiologic shoulder simulator, driven using simulated muscle force, was developed to dynamically realize accurate kinematic control in all three rotational degrees of freedom (DOF) under physiological kinetic boundaries. The control algorithm of the simulator was implemented using three parallel running independent control loops, which regulate the forces of individual muscles in the respect DOF and work asynchronously in disparate sequences adapted to specific motions (abduction, flexion/extension and rotation).

Predictive simulation of post-stroke gait with functional electrical stimulation.

Post-stroke patients present various gait abnormalities such as drop foot, stiff-knee gait (SKG), and knee hyperextension. Functional electrical stimulation (FES) improves drop foot gait although the mechanistic basis for this effect is not well understood. To answer this question, we evaluated the gait of a post-stroke patient walking with and without FES by inverse dynamics analysis and compared the results to an optimal control framework.

Experimental evaluation of precision and accuracy of RSA in the lumbar spine.

Purpose: Roentgen stereophotogrammetric analysis is a technique to make accurate assessments of the relative position and orientation of bone structures and implants in vivo. While the precision and accuracy of stereophotogrammetry for hip and knee arthroplasty is well documented, there is insufficient knowledge of the technique's precision and, especially accuracy when applied to rotational movements in the spinal region.

Methods: The motion of one cadaver lumbar spine segment (L3/L4) was analyzed in flexion-extension, lateral bending and internal rotation.

Biomechanical Assessment of Three Osteosynthesis Constructs by Periprosthetic Humerus Fractures.

Background: Biomechanical stability assessment of 3 different constructs for proximal fixation of a locking compression plate (LCP) in treating a Worland type C periprosthetic fracture after total shoulder arthroplasty.

Methods: 27 Worland type C fractures after shoulder arthroplasty in synthetic humeri were treated with 14-hole LCP that is proximally fixed using the following: (1) 1 × 1.5 mm cerclage wires and 2x unicortical-locking screws, (2) 3 × 1.

Is the strain pattern of conventional stems negatively affected by a previously short stem THA? An experimental study in cadavaric bone.

Background: A short stem hip arthroplasty can be revised in many cases using a conventional stem. Furthermore, in some cases the implantation of a short stem is intended, but intraoperatively reasons may lead to the decision to implant a conventional stem after previous preparation of a short stem.

Objective: In both cases it is questionable if the anchorage of a conventional stem is negatively affected by the previous preparation of a short stem.

Anatomic factors influencing the anterior stability of reverse total shoulder arthroplasty.

Background: Several factors affect the stability of the reverse shoulder arthroplasty. The influence of bony anatomy on anterior stability remains unclear. This study aimed to identify the correlations between bony anatomy and anterior dislocation forces.

Greater early migration of a short-stem total hip arthroplasty is not associated with an increased risk of osseointegration failure: 5th-year results from a prospective RSA study with 39 patients, a follow-up study.

Background and purpose - Short-stem hip arthroplasty has been a viable alternative to standard stems for the treatment of hip osteoarthritis for over 10 years. This study assessed whether a correlation existed between a greater initial increase in implant migration and inferior clinical outcomes at 5 years postoperatively. Results on these patients after 2 years have been published previously.

A short stem with metaphyseal anchorage reveals a more physiological strain pattern compared to a standard stem - an experimental study in cadavaric bone.

Purpose: The proposed advantages of short stem hip arthroplasties are bone preserving strategies and less soft tissue damage. Bone preserving strategies do not only include a more proximal resection of the femoral neck, but especially for short stem hip arthroplasties with predominantly metaphyseal fixation a presumed more physiologic load transfer and thus a reduction of stress-shielding. However, the hypothesized metaphyseal anchorage associated with the aforementioned benefits still needs to be verified.

Force, impulse and energy during falling with and without knee protection: an in-vitro study.

The mechanics of protective knee padding mitigating injury from a high-force fall have not been investigated in real-life scenarios to date. This study compares the effect of wearing knee pads to unprotected impact on a hard surface. We hypothesized that knee pads reduce the force and energy transmitted to the bony structures of the knee cap compared with unprotected conditions.

The Laxity of the Native Knee: A Meta-Analysis of in Vitro Studies.

Background: Although soft-tissue balancing plays an important role in knee arthroplasty, we are aware of no objective target parameters describing the soft-tissue tension of the native knee. In the present study, we aimed to meta-analyze data from studies investigating native knee laxity to create a guide for creating a naturally balanced knee joint.

Methods: PubMed and Web of Science were searched for studies with laxity data published from 1996 through 2016.

The prevalence of osteoarthritis: Higher risk after transfemoral amputation?-A database analysis with 1,569 amputees and matched controls.

Background: Several studies have shown that patients with a unilateral amputation have an increased risk of developing osteoarthritis (OA) in the knee of their sound leg. OBJECTIVE: The first objective was to investigate whether amputees are more frequently affected by gon-, cox- or polyarthritis as well as back pain or spinal disorders. We hypothesized that mobile and active transfemoral amputees more often experience OA and spinal disorders than non-amputees.

Effect of the humeral neck-shaft angle and glenosphere lateralization on stability of reverse shoulder arthroplasty: a cadaveric study.

Background: Lateralizing the glenosphere and decreasing the humeral neck-shaft angles are implant design parameters that reduce the risk of scapular impingement. The effects of these parameters on joint stability remain unclear. This study evaluated the effect of glenosphere lateralization and humeral neck-shaft angle on joint stability by quantifying the anterior dislocation force in different arm positions.