Range of motion after 1, 2, and 3 level cervical disc arthroplasty.

Background: Motion of a solid body involves translation and rotation. Few investigations examine the isolated translational and rotational components associated with disc arthroplasty devices. This study investigates single- and multi-level cervical disc arthroplasty with respect to index and adjacent level range of motion.

Transfixation of the Sacroiliac Joint: Biomechanical Stability of a Dual-Implant Minimally Invasive Procedure.

Background: Despite minimally invasive techniques for sacroiliac joint fixation, clinical challenges remain. The investigators hypothesized the studied technique will transfix the sacroiliac joint to a level comparable to the intact sacroiliac joint.

Objectives: The study objective was to determine the dynamic stability of a square inter-joint implant using a triangular notch in opposing bone segments spanning the joint space.

Endplate Deformation Due to Open and Strutted Intervertebral Devices.

Background: There is an absence of work on vertebral endplate response to peripheral loading following disc removal and interbody placement. Endplate deflection into the interbody space may impart beneficial strain on the developing fusion mass, influencing bone formation and remodeling. The aim of this study was to verify endplate deformation due to peripheral loading using a custom transducer and to investigate whether endplate motion is inhibited by implant design.

Differences in femoral morphology among the Orientals and Caucasians: a comparative study using plain radiographs.

The purpose of this study was to identify the differences in femoral dimensions among Caucasian and Oriental populations. A total of 268 femora were collected from China, Japan, Korea, Taiwan and the United States. Firstly, the dimensional parameters for measuring femur were identified.

Segmental bone replacement via patient-specific, three-dimensional printed bioresorbable graft substitutes and their use as templates for the culture of mesenchymal stem cells under mechanical stimulation at various frequencies.

The treatment of large segmental bone defects remains a challenge as infection, delayed union, and nonunion are common postoperative complications. A three-dimensional printed bioresorbable and physiologically load-sustaining graft substitute was developed to mimic native bone tissue for segmental bone repair. Fabricated from polylactic acid, this graft substitute is novel as it is readily customizable to accommodate the particular size and location of the segmental bone of the patient to be replaced.

Substrate effects on cell-envelope deformation during early-stage Staphylococcus aureus biofilm formation.

Bacterial adhesion to a surface is the first step in biofilm formation, and adhesive forces between the surface and a bacterium are believed to give rise to planktonic-to-biofilm phenotypic changes. Here we use Focused-Ion-Beam (FIB) tomography with backscattered scanning electron microscopy (SEM) to image Staphyolococcus aureus (S. aureus) biofilms grown on Au-coated polystyrene (PS) and Au-coated PS modified by mixed thiols of triethylene glycol mono-11-mercaptoundecyl ether (EG) and 1-dodecanethiol (CH).

Disease severity and treatment in adolescent idiopathic scoliosis: the impact of race and economic status.

Background Context: Ethnic disparities have been documented in the incidence and treatment of many diseases. Additionally, race and socioeconomic status (SES) have been shown to affect disease severity and access to care in the recent orthopedic literature.

Purpose: To assess the role, if any, that race, SES, and health insurance type play in disease severity and treatment decisions in patients with adolescent idiopathic scoliosis.

Predicting operative blood loss during spinal fusion for adolescent idiopathic scoliosis.

Background: Patient and surgical factors are known to influence operative blood loss in spinal fusion for adolescent idiopathic scoliosis (AIS), but have only been loosely identified. To date, there are no established recommendations to guide decisions to predonate autologous blood, and the current practice is based primarily on surgeon preference. This study is designed to determine which patient and surgical factors are correlated with, and predictive of, blood loss during spinal fusion for AIS.

Radially and axially graded multizonal bone graft substitutes targeting critical-sized bone defects from polycaprolactone/hydroxyapatite/tricalcium phosphate.

Repair and regeneration of critical sized defects via the utilization of polymeric bone graft substitutes are challenges. Here, we introduce radially and axially graded multizonal bone graft substitutes fabricated from polycaprolactone (PCL), and PCL biocomposites with osteoconductive particles, that is, hydroxyapatite (HA), and β-tricalcium phosphate (TCP). The novel bone graft substitutes should provide a greater degree of freedom to the orthopedic surgeon especially for repair of critically sized bone defects.

Unitary bioresorbable cage/core bone graft substitutes for spinal arthrodesis coextruded from polycaprolactone biocomposites.

A unitary bioresorbable cage/core bone graft substitute consisting of a stiff cage and a softer core with interconnected porosity is offered for spinal arthrodesis. Polycaprolactone, PCL, was used as the matrix and hydroxyapatite, HA, and β-tricalcium phosphate, TCP, were used in the formulation of the cage layer to impart modulus increase and osteoconductivity while the core consisted solely of PCL. The crystallinity, biodegradation rate (under accelerated conditions) and mechanical properties, i.

In vitro analysis and mechanical properties of twin screw extruded single-layered and coextruded multilayered poly(caprolactone) scaffolds seeded with human fetal osteoblasts for bone tissue engineering.

In vitro culturing and mechanical properties of three types of three-dimensional poly(caprolactone) scaffolds with interconnecting open-foam networks are reported. The scaffolds targeted bone tissue regeneration and were fabricated using twin screw extrusion and coextrusion techniques, for continuous mixing/shaping and formation of single or multilayers with distinct and tailorable porosities and pore sizes. Human fetal preosteoblastic cells, hFOB, were cultured on the extruded and coextruded scaffolds under osteogenic supplements and the samples of the resulting tissue constructs were removed and characterized for cell viability and proliferation using the MTS assay, differentiation, and mineralized matrix synthesis via the alkaline phosphatase, ALP, activity and Alizarin Red staining and cell migration using confocal microscopy and scanning electron microscopy.

Maximal pulmonary recovery after spinal fusion for adolescent idiopathic scoliosis: how do anterior approaches compare?

Study Design: Retrospective analysis of prospectively collected data.

Objective: To compare the relative rates of pulmonary recovery and maximal pulmonary function with surgical approach.

Summary Of Background Data: Anterior versus posterior spinal fusion (ASF, PSF) for the treatment of adolescent idiopathic scoliosis (AIS) has been debated.

The treatment of vertebral and chest wall deformities with expandable thoracoplasty and a prosthetic expandable implant.

Background: Expansion thoracoplasty is a temporary solution to allow complete pulomonary development in the setting of vertebral and rib cage deformities. After thoracoplasty, an expandable implant is needed to maintain the correction. The Growing Spine Profiler (GSP) is a new type of readjustable rib distracter.

Biomechanical analysis of a disc prosthesis distal to a scoliosis model.

Study Design: Biomechanical study of bovine spines.

Objective: The purpose of this study was to perform a biomechanical test to analyze intervertebral deflections following placement of both 1 and 2 semiconstrained TDRs in the subjacent segments of a long fusion.

Summary Of Background Data: Long-term sequela of long lumbar fusion for scoliosis include adjacent segment disease and flatback syndrome.

Torsional stability of cross-link configurations: a biomechanical analysis.

Background Context: Cross-link systems have been used to augment segmental spinal instrumentation since the earliest introduction of these fixation systems. Although transverse cross-links have little impact on sagittal motion of spinal constructs, cross-linkage does affect torsional rigidity. Despite the wide variety of cross-link designs, almost all have been configured as transverse devices.

The use of outcomes instruments in the assessment of patients with idiopathic scoliosis.

Outcomes research is becoming an increasingly vital aspect of modern medicine. With current cost containment measures, the need for effective and reproducible treatment options is essential. The methodology associated with these outcomes studies is varied.

A biomechanical comparison of posterior cruciate ligament reconstructions using single- and double-bundle tibial inlay techniques.

Background: The efficacy of using a double-bundle versus single-bundle graft for posterior cruciate ligament reconstruction has not been demonstrated.

Hypothesis: A double-bundle graft restores knee kinematics better than a single-bundle graft does in tibial inlay PCL reconstructions.

Study Design: Controlled laboratory study.

The effect of humeral component anteversion on shoulder stability with glenoid component retroversion.

Background: Posterior glenoid bone loss is often seen in association with glenohumeral osteoarthritis. This posterior asymmetric wear can lead to retroversion of the glenoid component and posterior instability after total shoulder arthroplasty. Options for the treatment of this asymmetric wear include eccentric reaming of the so-called high side, bone-grafting, and/or anteverting the humeral component.

Selective retention of bone marrow-derived cells to enhance spinal fusion.

Connective tissue progenitors can be concentrated rapidly from fresh bone marrow aspirates using some porous matrices as a surface for cell attachment and selective retention, and for creating a cellular graft that is enriched with respect to the number of progenitor cells. We evaluated the potential value of this method using demineralized cortical bone powder as the matrix. Matrix alone, matrix plus marrow, and matrix enriched with marrow cells were compared in an established canine spinal fusion model.

Design and evaluation of the FlexiCore metal-on-metal intervertebral disc prosthesis.

Background Context: The technical difficulties associated with the development of an intervertebral disc prosthesis include endurance demands on the device, lack of consensus concerning the biomechanical principles governing the articulation of the spinal joint and the performance of materials available for implantation.

Purpose: Although biologically based disc prostheses and augmentations may be the endpoint of spinal disc replacements, these devices and associated technologies will still require decades of work in order to achieve fruition. The more immediate solution will require a durable, biocompatible device capable of restoring range of motion.

Evaluation of the biological response of wear debris.

Study Design: An animal study was conducted to evaluate the biological response to titanium particles from an artificial intervertebral disc in terms of serology and histologic changes.

Objectives: To determine the biological response to wear debris in the retroperitoneal and epidural space.

Summary Of Background Data: Few wear studies exist about mechanical artificial discs.

Ultra high molecular weight polyethylene (UHMWPE) model can provide results comparable to cadaveric models.

The in vitro biomechanical models using a cadaveric spine specimen have long been used in understanding normal and abnormal functions of spines as well as for strength and stability testing of the spine specimen or spinal construct. Little effort has been made to describe the similarities or differences between UHMWPE and cadaveric models. Eight cadaveric lumbar spines were harvested generating six FSU and three corpectomy models.

A comparison of stainless steel and CP titanium rods for the anterior instrumentation of scoliosis.

Use of 4.0 mm and 5.0 mm steel rods have resulted in proximal screw pullout.

Spine fusion using cell matrix composites enriched in bone marrow-derived cells.

Bone marrow-derived cells including osteoblastic progenitors can be concentrated rapidly from bone marrow aspirates using the surface of selected implantable matrices for selective cell attachment. Concentration of cells in this way to produce an enriched cellular composite graft improves graft efficacy. The current study was designed to test the hypothesis that the biologic milieu of a bone marrow clot will significantly improve the efficacy of such a graft.

Non-linear fitting of mechanical data for efficacy determination of single versus double bundle Achilles tendon grafts for PCL reconstructions.

The Posterior Cruciate Ligament (PCL) consists of two primary bundles and is the primary restraint to posterior tibial translation. The emergence of the Posterior Tibial Inlay Technique (PTIT) has demonstrated a mechanical advantage over the commonly used Tibial Tunnel Method (TTM). This study was designed to investigate the effects on knee mechanics from both a Single-bundle (SB) and Double-bundle (DB) Achilles tendon PCL reconstruction using a PTIT.