Adherence Monitor for Measurement of Removable Cast Walker Wear-Time: Multiple Sensors and Predictive Analytics Improve Accuracy.

Background: Treatment of diabetes and its complications is a primary health care expense. Up to 25% of people with diabetes will develop diabetic foot ulcers (DFUs). Removable cast walker (RCW) boots commonly prescribed for DFU treatment, promote healing, and provide offloading and wound protection.

Prosthesis design and likelihood of achieving physiological range of motion after cervical disc arthroplasty: analysis of range of motion data from 1,173 patients from 7 IDE clinical trials.

Background Context: The functional goals of cervical disc arthroplasty (CDA) are to restore enough range of motion (ROM) to reduce the risk of accelerated adjacent segment degeneration but limit excessive motion to maintain a biomechanically stable index segment. This motion-range is termed the "Physiological mobility range." Clinical studies report postoperative ROM averaged over all study subjects but they do not report what proportion of reconstructed segments yield ROM in the Physiological mobility range following CDA surgery.

Coupled rotation patterns in cervical spine axial rotation can change when the head is kept level.

The biomechanical literature describes axial rotation occurring coupled with lateral bending and flexion in the cervical spine. Since the head is kept level during some activities of daily living, we set out to investigate the changes in total and segmental motion that occur when a level gaze constraint is applied to cadaveric cervical spine specimens during axial rotation. 1.

Republication of "A Biomechanical Comparison of Limited Open Versus Krackow Repair for Achilles Tendon Rupture".

Background: Soft tissue complications after Achilles tendon repair has led to increased interest in less invasive techniques. Various limited open techniques have gained popularity as an alternative to open operative repair. The purpose of this study was to biomechanically compare an open Krackow and limited open repair for Achilles tendon rupture.

Bone cutting efficiency and heat generation using a traditional fluted Burr and a novel fluteless resurfacing tool.

Background: Powered instrumentation is often used for bone preparation and/or removal in many orthopaedic procedures but does risk thermogenesis. This study compares biomechanical properties of a fluted burr and a novel fluteless resurfacing tool.

Methods: Twenty cadaveric metatarsals were tested with four predetermined cutting forces to evaluate heat generation and cutting rate for the fluted burr and fluteless resurfacing tool over 40 s or until a depth of 4 mm was reached.

Comparison of the biomechanical stability of transverse and oblique screw trajectories in retrograde intramedullary nailing of supracondylar femur fractures.

Background: The goal was to determine the effect of addition of oblique trajectory distal interlock screws to a retrograde intramedullary femoral nail on implant stability (stiffness), cycles to failure and mode of failure. The hypothesis was that addition of oblique screws would increase implant stability and number of loading cycles to failure.

Methods: Eight matched pairs were tested; one femur implanted with a femoral nail with only transverse distal interlock screws and the other with transverse and oblique interlock screws.

Kinematics of a cervical disc prosthesis implanted above or below one- and two-level fusions.

Background: The theoretical advantages of hybrid constructs over multi-level fusion have been illustrated in clinical and biomechanical studies. However, there is no biomechanical data on hybrid constructs using load control analyses. There is also no clear data on whether there is a biomechanical difference if the arthroplasty is below or above a 1- or 2-level fusion.

Biomechanics of Cervical Disc Arthroplasty Devices.

Prosthesis design has an influence on the quantity and quality of postoperative motion after cervical disc arthroplasty. Prostheses with built-in resistance to angular and translational motion may have an advantage in restoring physiologic motion. The ability of a prosthesis to work with remaining bony and soft tissues to restore motion and load-sharing is a function of the kinematic degrees of freedom DOF, axis of rotation for a given motion, and device stiffness.

Effect of K-wire Reuse and Drill Mode on Heat Generation in Bone.

Background: We examined the effect of Kirschner wire (K-wire) reuse and use of oscillating mode on heat generation within cortical bone.

Methods: Two trocar-tipped K-wires were drilled through the diaphysis of each of 30 human metacarpals and phalanges: one K-wire was inserted in rotary mode and another in oscillating mode. Each wire was reused once.

Osteoinductivity and biomechanical assessment of a 3D printed demineralized bone matrix-ceramic composite in a rat spine fusion model.

We recently developed a recombinant growth factor-free bone regenerative scaffold composed of stoichiometric hydroxyapatite (HA) ceramic particles and human demineralized bone matrix (DBM) particles (HA-DBM). Here, we performed the first pre-clinical comparative evaluation of HA-DBM relative to the industry standard and established positive control, recombinant human bone morphogenetic protein-2 (rhBMP-2), using a rat posterolateral spinal fusion model (PLF). Female Sprague-Dawley rats underwent bilateral L4-L5 PLF with implantation of the HA-DBM scaffold or rhBMP-2.

Loading of the lumbar spine during transition from standing to sitting: effect of fusion versus motion preservation at L4-L5 and L5-S1.

Background Context: Transition from standing to sitting significantly decreases lumbar lordosis with the greatest lordosis-loss occurring at L4-S1. Fusing L4-S1 eliminates motion and thus the proximal mobile segments maybe recruited during transition from standing to sitting to compensate for the loss of L4-S1 mobility. This may subject proximal segments to supra-physiologic flexion loading.

Biomechanics of Cervical Disc Arthroplasty-A Review of Concepts and Current Technology.

Activities of daily living require the subaxial cervical spine (C2-C7) to have substantial mobility. Cervical degenerative changes can cause abnormal motions and altered load distribution, leading to pain and limiting the ability of individuals to perform activities of daily living. Anterior cervical discectomy and fusion (ACDF) has been widely used to treat symptomatic cervical spondylosis.

Correction to: Prosthesis design influences segmental contribution to total cervical motion after cervical disc arthroplasty.

Unfortunately, figures 1 and 2 have been incorrectly published in the original publication. The complete correct figures are given below with the captions.

Estimation of Trunk Muscle Forces Using a Bio-Inspired Control Strategy Implemented in a Neuro-Osteo-Ligamentous Finite Element Model of the Lumbar Spine.

Low back pain (LBP), the leading cause of disability worldwide, remains one of the most common and challenging problems in occupational musculoskeletal disorders. The effective assessment of LBP injury risk, and the design of appropriate treatment modalities and rehabilitation protocols, require accurate estimation of the mechanical spinal loads during different activities. This study aimed to: (1) develop a novel 2D beam-column finite element control-based model of the lumbar spine and compare its predictions for muscle forces and spinal loads to those resulting from a geometrically matched equilibrium-based model; (2) test, using the foregoing control-based finite element model, the validity of the follower load (FL) concept suggested in the geometrically matched model; and (3) investigate the effect of change in the magnitude of the external load on trunk muscle activation patterns.

Effectiveness of cervical zero profile integrated cage with and without supplemental posterior Interfacet stabilization.

Background: Conditions requiring cervical decompression and stabilization are commonly treated using anterior cervical discectomy and fusion using an anterior cage-plate construct. Anterior zero profile integrated cages are an alternative to a cage-plate construct, but literature suggests they may result in less motion reduction. Interfacet cages may improve integrated cage stability.

Characterising acetabular component orientation with pelvic motion during total hip arthroplasty.

Introduction: Suboptimal acetabular component position can result in impingement, dislocation, and accelerated wear. Intraoperative pelvic motion has led to surgeon error and acetabular cup malposition. This study characterises the relationship between pelvic rotation and postoperative acetabular cup orientation.

Neutral cervical sagittal vertical axis and cervical lordosis vary with T1 tilt.

Objective: The authors conducted a study to determine whether a change in T1 tilt results in a compensatory change in the cervical sagittal vertical axis (SVA) in a cadaveric spine model.

Methods: Six fresh-frozen cadavers (occiput [C0]-T1) were cleaned of soft tissue and mounted on a customized test apparatus. A 5-kg mass was applied to simulate head weight.

Kinematic assessment of an elastic-core cervical disc prosthesis in one and two-level constructs.

Introduction: Anterior cervical discectomy and fusion has been associated with the development of adjacent segment degeneration (ASD), with clinical incidence of approximately 3% per year. Cervical total disc arthroplasty (TDA) has been proposed as an alternative to prevent ASD.

Hypotheses: TDA in optimal placement using an elastic-core cervical disc (RHINE, K2M Inc.

Prosthesis design influences segmental contribution to total cervical motion after cervical disc arthroplasty.

Introduction: We investigated a new metric for assessing the quality of motion of the cervical segments over the arc of extension-to-flexion motion after cervical disc arthroplasty (CDA). We quantified: (1) the amount of motion contributed by individual spinal segments to the total cervical spine motion, termed segmental motion fraction, and its variation throughout the arc of extension-to-flexion motion and (2) how cervical disc arthroplasty using two distinct prosthesis designs may influence the segmental motion contributions.

Materials And Methods: We tested 16 human C3-T1 spine specimens under physiologic loads; first intact, after CDA at C5-C6, and then at C5-C6 and C6-C7.

Anatomic considerations in headaches associated with cervical sagittal imbalance: A cadaveric biomechanical study.

Chronic Forward Head Posture is associated with headaches, neck pain, and disability, though few studies have investigated the effects it has on the suboccipital triangle. The objective of this study was to quantitatively assess whether the biomechanical changes in the suboccipital triangle help explain the clinical manifestations of Forward Head Posture. Specifically, this study aimed to identify whether the Greater Occipital Nerve or C2 nerve root may be compressed in Forward Head Posture.

Motion response of a polycrystalline diamond adaptive axis of rotation cervical total disc arthroplasty.

Background: Cervical fusion is associated with adjacent segment degeneration. Cervical disc arthroplasty is considered an alternative to reduce risk of adjacent segment disease. Kinematics after arthroplasty should closely replicate healthy in vivo kinematics to reduce adjacent segment stresses.

The Effect of Proton Pump Inhibitors on Bone Formation in a Rat Spinal Arthrodesis Model.

Study Design: Rat posterolateral arthrodesis model.

Objective: Quantify the impact of administration of a proton pump inhibitor on spine fusion.

Summary Of Background Data: Proton pump inhibitors (PPIs) are widely used for gastrointestinal disorders and for ulcer prophylaxis in patients taking non-steroidal anti-inflammatory drugs.

Biomechanics of an Expandable Lumbar Interbody Fusion Cage Deployed Through Transforaminal Approach.

Background: A novel expandable lumbar interbody fusion cage has been developed which allows for a broad endplate footprint similar to an anterior lumbar interbody fusion; however, it is deployed from a minimally invasive transforaminal unilateral approach. The perceived benefit is a stable circumferential fusion from a single approach that maintains the anterior tension band of the anterior longitudinal ligament. The purpose of this biomechanics laboratory study was to evaluate the biomechanical stability of an expandable lumbar interbody cage inserted using a transforaminal approach and deployed in situ compared to a traditional lumbar interbody cage inserted using an anterior approach (control device).