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Budge M.D.,Beaumont Health System | Heisey M.H.,Mid Michigan Orthopaedic Institute | Baker K.,Orthopaedic Research Laboratories | Wiater J.M.,Beaumont Health System | Wiater J.M.,Oakland University
Journal of Shoulder and Elbow Surgery | Year: 2013

Background: Aseptic loosening of all-polyethylene glenoid components remains a limiting factor in achieving long-term implant survival in total shoulder arthroplasty (TSA). This study prospectively evaluated the functional and radiographic outcomes of patients undergoing TSA with a novel, porous, tantalum-backed glenoid component, with a minimum 2 years of follow-up. Materials and methods: Porous tantalum-backed glenoid components were used in 19 TSAs in 19 patients. All patients were available for radiographic follow-up at an average of 38 months (range, 24-64 months). Patients were evaluated prospectively using the American Shoulder and Elbow Surgeons (ASES) score and pain on a visual analog scale (VAS). Radiographs were evaluated for component loosening and failure of the porous tantalum backing at a minimum 2 years of follow-up. Results: The mean VAS decreased from 8.6 to 2.9 (P < .0001). The mean ASES score improved from 21 to 70 points (P < .05). Mean active forward elevation improved from 75° to 131° (P < .0001). At latest follow-up, all glenoid components except 1 had complete in-growth of the porous tantalum keel; however, 4 components (21%) failed by fracture at the keel-glenoid face junction. Conclusions: There was an unacceptably high rate of glenoid component failure (21%) due to fracture at the keel-glenoid face junction in this series. The manufacturer has subsequently revised this early design to reduce the risk of failure. The results of this study illustrate that caution should be exercised in the use of novel implants with an unproven clinical track record. © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Source

Parvizi J.,Thomas Jefferson University | Adeli B.,Thomas Jefferson University | Zmistowski B.,Thomas Jefferson University | Restrepo C.,Thomas Jefferson University | Greenwald A.S.,Orthopaedic Research Laboratories
Journal of Bone and Joint Surgery - Series A | Year: 2012

Periprosthetic joint infection continues to frustrate the medical community. Although the demand for total joint arthroplasty is increasing, the burden of such infections is increasing even more rapidly, and they pose a unique challenge because their accurate diagnosis and eradication can prove elusive. This review describes the current knowledge regarding diagnosis and treatment of periprosthetic joint infection. A number of tools are available to aid in establishing a diagnosis of periprosthetic joint infection. These include the erythrocyte sedimentation rate, serum C-reactive protein concentration, synovial white blood-cell count and differential, imaging studies, tissue specimen culturing, and histological analysis. Multiple definitions of periprosthetic joint infection have been proposed but there is no consensus. Tools under investigation to diagnose such infections include the C-reactive protein concentration in the joint fluid, point-of-care strip tests for the leukocyte esterase concentration in the joint fluid, and other molecular markers of periprosthetic joint infection. Treatment options include irrigation and debridement with prosthesis retention, one-stage prosthesis exchange, two-stage prosthesis exchange with intervening placement of an antibiotic-loaded spacer, and salvage treatments such as joint arthrodesis and amputation. Treatment selection is dependent on multiple factors including the timing of the symptom onset, patient health, the infecting organism, and a history of infection in the joint. Although prosthesis retention has the theoretical advantages of decreased morbidity and improved return to function, two-stage exchange provides a lower rate of recurrent infection. As the burden of periprosthetic joint infection increases, the orthopaedic and medical community should become more familiar with the disease. It is hoped that the tools currently under investigation will aid clinicians in diagnosing periprosthetic joint infection in an accurate and timely fashion to allow appropriate treatment. Given the current knowledge and planned future research, the medical community should be prepared to effectively manage this increasingly prevalent disease. Copyright © 2012 by The Journal of Bone and Joint Surgery, Incorporated. Source

Anderst W.J.,University of Pittsburgh | Anderst W.J.,Orthopaedic Research Laboratories | Baillargeon E.,University of Pittsburgh | Donaldson W.F.,University of Pittsburgh | And 2 more authors.
Spine | Year: 2011

Study Design. In vivo validation during functional loading. Objective. To determine the accuracy and repeatability of a model-based tracking technique that combines subject-specific computed tomographic (CT) models and high-speed biplane X-ray images to measure three-dimensional (3D) in vivo cervical spine motion. Summary Of Background Data. Accurate 3D spine motion is difficult to obtain in vivo during physiological loading because of the inability to directly attach measurement equipment to individual vertebrae. Previous measurement systems were limited by two-dimensional (2D) results and/or their need for manual identification of anatomical landmarks, precipitating unreliable and inaccurate results. All previous techniques lack the ability to capture true 3D motion during dynamic functional loading. Methods. Three subjects had 1.0-mm-diameter tantalum beads implanted into their fused and adjacent vertebrae during anterior cervical discectomy and fusion surgery. High-resolution CT scans were obtained after surgery and used to create subject-specific 3D models of each cervical vertebra. Biplane X-ray images were collected at 30 frames per second while the subjects performed flexion/extension and axial rotation movements 6 months after surgery. Individual bone motion, intervertebral kinematics, and arthrokinematics derived from dynamic radiostereophotogrammetric analysis served as a gold standard to evaluate the accuracy of the model-based tracking technique. Results. Individual bones were tracked with an average precision of 0.19 and 0.33 mm in nonfused and fused bones, respectively. Precision in measuring 3D joint kinematics in fused and adjacent segments averaged 0.4 mm for translations and 1.1° for rotations, while anterior and posterior disc height above and below the fusion were measured with a precision ranging between 0.2 and 0.4 mm. The variability in 3D joint kinematics associated with tracking the same trial repeatedly was 0.02 mm in translation and 0.06° in rotation. Conclusion. The 3D cervical spine motion can be precisely measured in vivo with submillimeter accuracy during functional loading without the need for bead implantation. Fusion instrumentation did not diminish the accuracy of kinematic and arthrokinematic results. The semiautomated model-based tracking technique has excellent repeatability. Copyright © 2011 Lippincott Williams &Wilkins. Source

Pifer M.A.,Beaumont Health System | Maerz T.,Orthopaedic Research Laboratories | Baker K.C.,Beaumont Health System | Anderson K.,Beaumont Health System
American Journal of Sports Medicine | Year: 2014

Background: Recent work has shown the presence of catabolic cytokines in platelet-rich plasma (PRP), but little is known about endogenous catabolic proteases such as matrix metalloproteinases (MMPs). Hypothesis/Purpose: To quantify MMP content in 2 commercially available PRP preparation systems: Arthrex Double Syringe System autologous conditioned plasma (ACP) and Biomet GPS (GPS). The hypothesis was that MMPs are actively secreted from PRP immediately after preparation. Study Design: Controlled laboratory study. Methods: PRP was prepared using either ACP (low platelet, low leukocyte) or GPS (high platelet, high leukocyte). MMP-2, MMP-3, and MMP-9 concentrations were measured using multiplex enzyme-linked immunosorbent assays for up to 6 days in 2 donors, and MMP activity was measured in 3 donors using kinetic activity kits able to detect the enzymatic cleavage of a fluorogenic peptide. Human ligament fibroblasts were cultured and exposed to both ACP and GPS from 1 donor each. MMP-2, -3, and -9 concentrations were assayed in culture media at 24 and 48 hours after exposure. Results: GPS exhibited higher total MMP-2, -3, and -9 concentrations for up to 144 hours of release, while ACP had higher platelet-normalized MMP-2 and MMP-3 concentrations. GPS had significantly higher total and endogenous MMP-2 activity (P = .004 and .014, respectively), MMP-3 activity (P = .020 and .015, respectively), and MMP-9 activity (P = .004 and .002, respectively) compared with ACP. Once normalized to platelet count, differences in MMP activity were not significant between ACP and GPS. Compared with controls, cells stimulated with interleukin-1 beta (IL-1β) and treated with ACP showed significantly higher fold changes of MMP-2 (P = .001) and MMP-3 (P = .003) concentrations at 24 hours than did cells treated with GPS. Total MMP-9 content was higher in the media of GPS-treated, IL-1β-stimulated cells compared with ACP-treated cells (P = .001). At 48 hours, IL-1β- stimulated cells treated with GPS exhibited higher fold changes of MMP-2 concentration (P = .002) compared with controls, but no difference in MMP-3 concentration was found. At 48 hours, there was a significantly higher concentration of MMP-9 in the cell culture media of ACP-treated cells compared with GPS-treated cells (P = .003). Conclusion: PRP prepared as both ACP and GPS contains MMP-2, -3, and -9, which is released over a period of at least 6 days. Furthermore, a large proportion of these MMPs are in their active form, and MMP activity is dependent on platelet count within the PRP preparation. Once exposed to ligament fibroblasts, both ACP and GPS cause the fibroblasts to release MMPs, most notably 24 hours after PRP exposure, and this release is dependent on prior IL-1β stimulation. Clinical Relevance: The results of this study demonstrate that PRP therapy delivers ng/mL-range concentrations of catabolic proteases, which could perpetuate inflammation and inhibit tissue healing. © 2014 The Author(s). Source

Tosi L.L.,Childrens National Health System | Warman M.L.,Orthopaedic Research Laboratories
Bone | Year: 2015

Rare bone diseases account for 5% of all birth defects and can cause significant morbidity throughout patients' lives. Significant progress is being made to elucidate the pathophysiological mechanisms underlying these diseases. This paper summarizes presentation highlights of a workshop on Rare Skeletal Diseases convened to explore how the study of rare diseases has influenced the field's understanding of bone anabolism and catabolism and directed the search for new therapies benefiting patients with rare conditions as well as patients with common skeletal disorders. © 2015. Source

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