Biomechanical Comparison of Three Locking Compression Plate Constructs from Three Manufacturers under Cyclic Torsional Loading in a Fracture Gap Model.

Objective:  The aim of the study was to compare the stiffness and cyclic fatigue of locking compression plate constructs from three manufacturers, DePuy Synthes (DPS), Knight Benedikt (KB), and Provet Veterinary Instrumentation (Vi), under cyclic torsion.

Methods:  The constructs of DPS, KB, and Vi were assembled by fixing a 10-hole 3.5-mm stainless steel locking compression plate 1 mm away from a validated bone model with a fracture gap of 47 mm.

Achilles and tail tendons of perlecan exon 3 null heparan sulphate deficient mice display surprising improvement in tendon tensile properties and altered collagen fibril organisation compared to C57BL/6 wild type mice.

The aim of this study was to determine the role of the perlecan (Hspg2) heparan sulphate (HS) side chains on cell and matrix homeostasis in tail and Achilles tendons in 3 and 12 week old exon 3 null HS deficient () and C57 BL/6 Wild Type (WT) mice. Perlecan has important cell regulatory and matrix organizational properties through HS mediated interactions with a range of growth factors and morphogens and with structural extracellular matrix glycoproteins which define tissue function and allow the resident cells to regulate tissue homeostasis. It was expected that ablation of the HS chains on perlecan would severely disrupt normal tendon organization and functional properties and it was envisaged that this study would better define the role of HS in normal tendon function and in tendon repair processes.

Dual-Energy Computed Tomography-How Accurate Is Gemstone Spectrum Imaging Metal Artefact Reduction? Its Application to Orthopedic Metal Implants.

Objective: To assess the accuracy and suitability of dual-energy computed tomography (DECT) in scanning metals used in orthopedic implants.

Materials And Methods: Four metal phantoms (Cobalt Chrome, Titanium Grade 5, Stainless Steel 316, and Stainless Steel 630), commonly used materials in orthopedic implants, were scanned by conventional, polychromatic CT as well as Gemstone Spectrum Imaging (GSI) DECT, with and without metal artefact reduction software (MARS). Scans were assessed for artefact based on Hounsfield unit values; and surfaces generated, based on a Canny edge detection algorithm.

Biomechanical comparison of metatarsal head designs in first metatarsophalangeal joint arthroplasty.

Background: Arthritis of the metatarsophalangeal (MTP) joint is characterized by loss of MTP joint range of motion (ROM) and pain. Joint arthroplasty is one treatment option, and while results can be satisfactory, there is still room for improvement. The aim was to use cadaveric model to compare the sagittal kinematics and articulating contact properties of 4 different first metatarsal head designs of an MTP joint implant.

Mechanical destabilization induced by controlled annular incision of the intervertebral disc dysregulates metalloproteinase expression and induces disc degeneration.

Study Design: An investigation of mechanical destabilization of the lumbar ovine intervertebral disc (IVD) inducing IVD degeneration (IVDD) as determined by multiparameter outcome measures (magnetic resonance imaging [MRI], IVD composition, biomechanical testing, gene profiling, immunohistochemistry, and immunoblotting).

Objective: To assess the effect of IVD mechanical destabilization on matrix protein and metalloproteinase gene expression to investigate the pathophysiological mechanisms of lumbar IVDD.

Summary Of Background Data: Several earlier studies have used annular transection to induce IVDD in sheep, but none have optimized or validated the most appropriate lesion size.

A detailed microscopic examination of alterations in normal anular structure induced by mechanical destabilization in an ovine model of disc degeneration.

Study Design: Microstructural investigation of anular structure.

Objective: To reveal the effect of mechanical destabilization on the anular architecture both locally and distantly.

Summary Of Background Data: Several longitudinal ovine-induced disc degeneration studies have documented degenerative changes in disc components using histologic, biomechanical, and biochemical approaches; however, changes in intervertebral disc (IVD) microstructure have largely remained neglected.

Effect of partial versus complete circumferential repair on flexor tendon strength in cadavers.

Purpose: This study investigated the strength of epitendinous repairs covering the palmar half of the tendon circumference only.

Methods: Two hundred porcine tendons were harvested from pig feet and separated into 2 equal groups. Group 1 tendons were sutured with a 2-strand core repair and group 2 tendons were sutured with a 4-strand core repair.

Frog glue enhances rotator cuff repair in a laboratory cadaveric model.

Summary: Rotator cuff tendons are typically reattached to the proximal humerus using transosseous sutures or suture anchors. Their primary mode of failure is at the tendon-bone interface. We investigated the addition of a novel adhesive secreted from a species of Australian frog (Notaden bennetti) to different methods of rotator cuff repair.

Immature sheep spines are more flexible than mature spines: an in vitro biomechanical study.

Study Design: Dynamic triaxial biomechanical testing of immature and mature ovine spine motion segments.

Objective: To compare torque-deflection parameters of mature and immature spine motion segments and to investigate whether scaling relationships apply between mature and immature motion segment torque-deflection responses.

Summary Of Background Data: While previous studies have examined the cervical region in a limited number of loading directions, a comprehensive multiaxial study of the response of the pediatric spine at all 3 spinal levels (cervical, thoracic, and lumbar) has not been performed.

Aggrecan, versican and type VI collagen are components of annular translamellar crossbridges in the intervertebral disc.

The aim of this study was to undertake a detailed analysis of the structure of the inter and intra-lamellar regions of the annulus fibrosus. A total of 30 newborn to 6 year-old lumbar ovine intervertebral discs (IVDs) were fixed and decalcified en-bloc to avoid differential swelling artifacts during processing and vertical mid-sagittal, and horizontal 4 mum sections were cut. These were stained with toluidine blue to visualise anionic proteoglycan (PG) species, H & E for cellular morphology and picro-sirius red (viewed under polarized light) to examine collagenous organization.

Dynamic biomechanics correlate with histopathology in human tibial cartilage: a preliminary study.

Improved staging of cartilage degeneration is required, particularly during early stages when minimal surface damage is visible arthroscopically. Degradation of articular cartilage extracellular matrix, resulting from degenerative changes associated with osteoarthritis, can influence its functional properties. Cartilage mechanical properties therefore may provide a quantitative method for monitoring degenerative change in this tissue.

Rotator cuff repair: an ex vivo analysis of suture anchor repair techniques on initial load to failure.

Purpose: To determine the best combination of anchors and suture techniques for repairing torn rotator cuff tendons.

Type Of Study: Ex vivo biomechanical investigation.

Methods: Sixty fresh-frozen sheep infraspinatus tendons were repaired using 6 different repair techniques: transosseous sutures with 2 sutures and mattress stitches; 2 suture anchors with 1 suture per anchor using either simple stitches, mattress stitches, or modified Kessler stitches; 2 suture anchors with 2 sutures per anchor using simple stitches; or 5 suture anchors with 1 suture per anchor and a mattress stitch pattern.

Deletion of iNOS gene impairs mouse fracture healing.

Nitric oxide (NO) is a signaling molecule synthesized from l-arginine by nitric oxide synthases (NOSs). NOS isoforms are either constitutive (endothelial NOS [eNOS] and neuronal NOS [nNOS]) or inducible NOS (iNOS). Previously, our group has reported that NO is expressed during and modulates fracture healing.

Topical glyceryl trinitrate application in the treatment of chronic supraspinatus tendinopathy: a randomized, double-blinded, placebo-controlled clinical trial.

Background: Topical glyceryl trinitrate therapy has previously demonstrated short-term pain reduction in patients with supraspinatus tendinopathy.

Hypothesis: Topical glyceryl trinitrate improves outcome measures in patients with supraspinatus tendinopathy.

Study Design: Randomized controlled clinical trial; Level of evidence, 1.

The nitric oxide donor glyceryl trinitrate increases subchondral bone sclerosis and cartilage degeneration following ovine meniscectomy.

Aim: To examine the effect of glyceryl trinitrate (GTN), a nitric oxide (NO) donor compound, on the concurrent progression of cartilage and subchondral bone changes in an ovine meniscectomy model of osteoarthritis (OA).

Methods: Bilateral lateral meniscectomy (MX) was performed on 12 ewes to induce OA. Six were treated with topical GTN (0.

Topical glyceryl trinitrate treatment of chronic noninsertional achilles tendinopathy. A randomized, double-blind, placebo-controlled trial.

Background: Noninsertional Achilles tendinopathy is a degenerative overuse disorder. No method has been universally successful in treating this condition. Topically applied nitric oxide has been shown, in animal models, to be effective for the treatment of fractures and cutaneous wounds through mechanisms that may include stimulation of collagen synthesis in fibroblasts.

Accuracy and reliability of a dynamic biomechanical skin measurement probe for the analysis of stiffness and viscoelasticity.

A novel instrument has been devised for the in vivo examination of the dynamic biomechanical properties of skin. These properties include stiffness and viscoelasticity. The advantage of the device is its ability to examine the skin dynamically, thereby eliminating preconditioning effects.

The Orthopaedic Research Institute-Tennis Elbow Testing System: A modified chair pick-up test-interrater and intrarater reliability testing and validity for monitoring lateral epicondylosis.

Lateral epicondylosis is a degenerative overuse tendinopathy involving the extensor tendons of the forearm, predominantly the extensor carpi radialis brevis, in the region of the lateral epicondyle of the elbow. The Orthopaedic Research Institute-Tennis Elbow Testing System (ORI-TETS) is designed to record objective measurements of force generated with a simulated chair pick-up test. Interrater reliability of the ORI-TETS was excellent, with high intraclass correlation coefficients (ICCs) for right arm mean peak force of 0.

Topical nitric oxide application in the treatment of chronic extensor tendinosis at the elbow: a randomized, double-blinded, placebo-controlled clinical trial.

Background: Extensor tendinosis ("tennis elbow") is a degenerative overuse tendinopathy of the wrist extensors at their attachment to the lateral humeral epicondyle. No treatment has been universally successful. Topical application of nitric oxide has been used effectively to treat fractures and cutaneous wounds in animal models, presumably by stimulation of collagen synthesis in fibroblasts.

Meniscal and chondral loss in the anterior cruciate ligament injured knee.

Rupture of the anterior cruciate ligament (ACL) of the knee is a commonly occurring injury in the athletic population. Associated meniscal and chondral injury is well recognised. This occurs both at the time of index injury and also secondarily over time in the ACL-deficient knee as a result of several related pathways culminating in osteoarthritis.

Rotator cuff repair with bioabsorbable screws: An in vivo and ex vivo investigation.

Purpose: The purpose of this study was to evaluate in vivo the clinical outcomes of rotator cuff repairs with bioabsorbable screws compared with metal suture anchors, and to compare the ex vivo initial load to failure of rotator cuff repairs using 3 different bioabsorbable screws, suture anchors, and transosseous sutures.

Type Of Study: In vivo clinical outcomes investigation, and ex vivo biomechanical study.

Methods: Three cohorts of patients with rotator cuff tears that measured less than 4 cm(2), were sequentially repaired with Mitek Rotator Cuff QuickAnchors (Mitek Surgical Products, Norwood, MA) (n = 9), Arthrex Headed Bio-Corkscrews (n = 9) (Arthrex, Naples, FL), and Mitek Rotator Cuff QuickAnchors (n = 9).

The Orthopaedic Research Institute-Ankle Strength Testing System: inter-rater and intra-rater reliability testing.

Achilles tendinosis is a degenerative overuse tendinopathy involving the primary ankle plantarflexors, namely the soleus and gastrocnemius muscles forming the tendo Achilles. The Orthopaedic Research Institute-Ankle Strength Testing System (ORI-ASTS) was designed to record objective measurements of force generated with a resisted ankle plantarflexion test. Testing normal subjects (n=6) was used to establish the reliability of the ORI-ASTS for measuring ankle plantarflexion force.