Applying the Techniques of Materials Science towards an Understanding of the Process of Canine Intervertebral Disc Degeneration.

Intervertebral disc degeneration in dogs occurs in an accelerated way and involves calcification, which is associated with disc herniation or extrusion. The degenerative process is complex and involves the transformation of collagen fibres, loss of proteoglycans and notochord cells and a reduction in water content; however, how these processes are linked to future disc extrusion remains unknown. We have employed techniques including Fourier Transform Infra-red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Uniaxial Compression Loading and Atomic Force Microscopy (AFM) in an attempt to gain a greater understanding of the degenerative process and its consequences on the physical properties of the disc.

Characterization of an advanced bone graft material with a nanocrystalline hydroxycarbanoapatite surface and dual phase composition.

The bone formation response of ceramic bone graft materials can be improved by modifying the material's surface and composition. A unique dual-phase ceramic bone graft material with a nanocrystalline, hydroxycarbanoapatite (HCA) surface and a calcium carbonate core (TrelCor®-Biogennix, Irvine, CA) was characterized through a variety of analytical methods. Scanning electron microscopy (SEM) of the TrelCor surface (magnification 100-100,000X) clearly demonstrated a nanosized crystalline structure covering the entire surface.

Effect of gamma irradiation and supercritical carbon dioxide sterilization with Novakill™ or ethanol on the fracture toughness of cortical bone.

Sterilization of structural bone allografts is a critical process prior to their clinical use in large cortical bone defects. Gamma irradiation protocols are known to affect tissue integrity in a dose dependent manner. Alternative sterilization treatments, such as supercritical carbon dioxide (SCCO ), are gaining popularity due to advantages such as minimal exposure to denaturants, the lack of toxic residues, superior tissue penetration, and minor impacts on mechanical properties including strength and stiffness.

Standalone titanium/polyetheretherketone interbody cage for anterior lumbar interbody fusion: Clinical and radiological results at 24 months.

Context: Anterior lumbar interbody fusion (ALIF) is a common procedure for patients suffering degenerative, deformity, or posttraumatic pathologies of the lumbar spine.

Aims: The aim of this study is to evaluate the clinical and radiological outcomes of a combination Titanium/Polyetheretherketone (Ti/PEEK) 3-screw fixation ALIF cage.

Settings And Design: This was a prospective multisurgeon series of 87 patients (105 implants), with a minimum 24-month follow-up.

Integral fixation titanium/polyetheretherketone cages for cervical arthrodesis: Two-year clinical outcomes and fusion rates using β-tricalcium phosphate or supercritical carbon dioxide treated allograft.

Context: Despite increasing promising reports regarding composite titanium (Ti)/PolyEtherEtherKetone (PEEK) cages, further longer-term, quality research is required. Synthetic bone graft substitutes are another rapidly developing area of spinal surgical research.

Aims: The purpose of this study is to evaluate the outcomes of an integral fixation composite Ti/PEEK cage for anterior cervical discectomy and fusion (ACDF) and compare a synthetic bone graft substitute (β-tricalcium phosphate; [βTCP]) with allograft processed using supercritical fluid technology.

Controlling the bone regeneration properties of bioactive glass: Effect of particle shape and size.

The ability of particulate bioactive glass to function as an effective bone graft material is directly related to its in vivo dissolution, ion release, and interparticle spacing (area associated with bone in-growth). A spherical shape represents an optimal geometry to control bioactive glass bone formation properties. Spherical particles were fabricated from 45S5 bioactive glass with unimodal (90-180, 180-355, and 355-500 μm) and bimodal size ranges (180-355/355-500 and 90-180/355-500 μm).

Load Sharing and Endplate Pressure Distribution in Anterior Interbody Fusion Influenced by Graft Choice.

Background: Cage subsidence is a known complication of spinal fusion. Various aspects of cage design have been investigated for their influence on cage subsidence, whereas the potential contribution of graft material to load sharing is often overlooked. We aimed to determine whether graft in the aperture affects endplate pressure distribution.

Comparative osteoconductivity of bone void fillers with antibiotics in a critical size bone defect model.

The study aimed to evaluate the comparative osteoconductivity of three commercially available bone void fillers containing gentamicin with respect to new bone, growth, host tissue response and resorption of the implant material. Defects were created in the cancellous bone of the distal femur and proximal tibia of 12-skeletally mature sheep and filled with three commercially available bone void fillers containing gentamicin (Stimulan-G, Cerament-G, Herafill-G). Peripheral blood was taken pre-operatively and at the time of implantation, as well as at intermittent timepoints following surgery to determine systemic gentamicin levels (5-,15- and 30- minutes, 1, 2, 3, 6, 12, 24, 48- and 72-hours, 3-, 6- and 12-weeks).

Bone ongrowth and mechanical fixation of implants in cortical and cancellous bone.

Background: What is the right surface for an implant to achieve biological fixation? Surface technologies can play important roles in encouraging interactions between the implant surface and the host bone to achieve osseointegration. Preclinical animal models provide important insight into in vivo performance related to bone ongrowth and implant fixation.

Methods: A large animal model was used to compare the in vivo response of HA and plasma-sprayed titanium coatings in a well-reported adult ovine model to evaluate bone ongrowth in terms of mechanical properties in cortical sites, and histology and histomorphometry in cortical and cancellous sites at 4 and 12 weeks.

Moment arm function dictates patella sagittal height anatomy: Rabbit epiphysiodesis model alters limb length ratios and subsequent patellofemoral anatomical development.

Patellofemoral anatomical dysplasia is associated with patellofemoral instability and pain. The closure of the knee physis occurs at the same age as the peak incidence of patellofemoral dislocation. This study determined the effect on the patellofemoral anatomical development in a rabbit epiphysiodesis model.

Performance of Seven Commercially Available Demineralized Bone Matrix Fiber and Putty Products in a Rat Posterolateral Fusion Model.

Demineralized bone matrix (DBM) is a widely used bone graft in spinal fusion. Most commercial DBMs are composed of demineralized bone particles (~125-800 microns) suspended in a carrier that provides improved handling but dilutes the osteoinductive component. DBM fibers (DBF) provide improved osteoconductivity and do not require a carrier.

Effects of SCCO, Gamma Irradiation, and Sodium Dodecyl Sulfate Treatments on the Initial Properties of Tendon Allografts.

Sterile and decellularized allograft tendons are viable biomaterials used in reconstructive surgeries for dense connective tissue injuries. Established allograft processing techniques including gamma irradiation and sodium dodecyl sulfate (SDS) can affect tissue integrity. Supercritical carbon dioxide (SCCO) represents a novel alternative that has the potential to decellularize and sterilize tendons with minimized exposure to denaturants, shortened treatment time, lack of toxic residues, and superior tissue penetration, and thus efficacy.

The use of demineralised bone fibres (DBF) in conjunction with supercritical carbon dioxide (SCCO) treated allograft in anterior lumbar interbody fusion (ALIF).

Spinal fusion is a common procedure for the treatment of various spinal pathologies. Since the early days, spinal fusion has been carried out with the use of bone grafts as interbody spacers. With the development of synthetic interbody implants, bone grafts were used to facilitate fusion.

The effect of surgery on patellar tendinopathy: Novel use of MRI questions the exploitability of the rat collagenase model to humans.

Background: patellar tendinopathy is an overuse condition most commonly affecting jumping athletes. Surgery is reserved for refractory cases; however, it lacks high level clinical evidence and basic science to support its use. The purpose of this study was to determine the biomechanical and histological response of surgical excision on patellar tendinopathy in the rat collagenase tendinopathy model and correlate MRI findings.

Does implantation site influence bone ingrowth into 3D-printed porous implants?

Background Context: The potential for osseointegration to provide biological fixation for implants may be related to anatomical site and loading conditions.

Purpose: To evaluate the influence of anatomical site on osseointegration of 3D-printed implants.

Study Design: A comparative preclinical study was performed evaluating bone ingrowth in cortical and cancellous sites in long bones as well as lumbar interbody fusion with posterior pedicle screw stabilization using the same 3D-printed titanium alloy design.

Evaluation of comparative soft tissue response to bone void fillers with antibiotics in a rabbit intramuscular model.

Management of osseous and soft tissue dead space can be a significant challenge in the clinical setting. Calcium sulphate and calcium phosphate-based biomaterials are increasingly being used as alternatives to PMMA for local release of antibiotics, in particular to fill dead space following surgical debridement. This study aims to observe the in-vivo absorption characteristics and tissue response of three commercially available calcium sulphate-based materials combined with gentamicin in an established soft tissue rabbit model.

Suture wear particles cause a significant inflammatory response in a murine synovial airpouch model.

Background: Commonly used contemporary orthopaedic sutures have been identified as a potential causative factor in the development of post-arthroscopic glenohumeral chondrolysis. Currently, little is known about the body's immune response to these materials. The aim of this study was to examine the biological response of synovial tissue to three commonly used orthopaedic sutures, using a murine airpouch model.

Corrosion of 3D-Printed Orthopaedic Implant Materials.

3D-printing technologies such as electron beam melting (EBM) have allowed for patient-specific orthopaedic implants, however differences generated from the fabrication process may alter the corrosion properties of Ti6Al4V implants. This study evaluated the corrosion characteristics of EBM-fabricated Ti6Al4V, alongside any linked microstructural and surface changes. EBM-fabricated Ti6Al4V and wrought Ti6Al4V specimens (n = 10 per group) underwent microstructural and surface characterisation before and after corrosion testing.

Effects of supercritical fluid CO and 25 kGy gamma irradiation on the initial mechanical properties and histological appearance of tendon allograft.

Tendon allografts, when autograft options are limited or when obtaining an autograft is not aligned with the patients' best interest, play an important role in tendon and ligament reconstruction. To minimize the risk of infectious disease transmission tissue banks perform screening tests and the allografts cleaned are sterilized. The current study examines and compares the initial mechanical properties and histological appearance of supercritical CO (SCCO)-treated and gamma-irradiated porcine extensor tendons.

Application of Calcium Sulfate for Dead Space Management in Soft Tissue: Characterisation of a Novel In Vivo Response.

Management of dead space (DS) is a fundamental aspect of surgery. Residual DS following surgery can fill with hematoma and provide an environment for bacterial growth, increasing the incidence of postoperative infection. Materials for managing DS include polymethyl-methacrylate (PMMA), which is nonresorbing and requires removal in a second surgical procedure.

A biomechanical comparison of Kirschner-wire fixation on fracture stability in Salter-Harris type I fractures of the proximal humeral physis in a porcine cadaveric model.

Background: The physis is the weakest component of immature long bones, and physeal fractures constitute about 30% of fractures in growing dogs. Fractures of the proximal humeral physis typically have a Salter Harris type I or II configuration. These fractures require accurate reduction and adequate stabilization to allow for any potential continued longitudinal bone growth, in conjunction with physeal fracture healing.

What Is the Standard Volume to Increase a Cup Size for Breast Augmentation Surgery? A Novel Three-Dimensional Computed Tomographic Approach.

Background: Breast augmentation surgery poses many challenges, and meeting the patient's expectations is one of the most important. Previous reports equate 100 cc to a one-cup-size increase; however, no studies have confirmed this between commercially available bras. The aim of this study was to identify the volume increase between cup sizes across different brands and the relationship with implant selection.

Critical Size Bone Defect Healing Using Collagen-Calcium Phosphate Bone Graft Materials.

The need for bone graft materials to fill bony voids or gaps that are not related to the intrinsic stability of the bone that arise due to trauma, tumors or osteolysis remains a clinically relevant and significant issue. The in vivo response of collagen-tricalcium phosphate bone graft substitutes was evaluated in a critical size cancellous defect model in skeletally mature rabbits. While the materials were chemically virtually identical, new bone formation, implant resorption and local in vivo responses were significantly different.

Development of a Novel Model for the Assessment of Dead-Space Management in Soft Tissue.

Following extensive surgical debridement in the treatment of infection, a "dead space" can result following surgical closure that can fill with hematoma, an environment conducive to bacterial growth. The eradication of dead space is essential in order to prevent recurrent infection. This study describes a novel small animal model to investigate dead-space management in muscle tissue.