Medicine and Health Sciences Commons^™

Staphylococcus Aureus Floating Biofilm Formation And Phenotype In Synovial Fluid Depends On Albumin, Fibrinogen, And Hyaluronic Acid, Samantha Knott, Dylan Curry, Neil Zhao, Pallavi Metgud, Sana Dastgheyb, Caroline Purtill, Marc I. Harwood, Md, Antonia F Chen, Thomas P Schaer, Michael Otto, Noreen J. Hickok

Department of Orthopaedic Surgery Faculty Papers

Biofilms are typically studied in bacterial media that allow the study of important properties such as bacterial growth. However, the results obtained in such media cannot take into account the bacterial localization/clustering caused by bacteria–protein interactions in vivo and the accompanying alterations in phenotype, virulence factor production, and ultimately antibiotic tolerance. We and others have reported that methicillin-resistant or methicillin-susceptible Staphylococcus aureus (MRSA or MSSA, respectively) and other pathogens assemble a proteinaceous matrix in synovial fluid. This proteinaceous bacterial aggregate is coated by a polysaccharide matrix as is characteristic of biofilms. In this study, we identify proteins important for this …

Collagen Structure-Function Mapping Informs Applications For Regenerative Medicine., James D San Antonio, Olena Jacenko, Andrzej Fertala, Joseph P R O Orgel

Department of Orthopaedic Surgery Faculty Papers

Type I collagen, the predominant protein of vertebrates, assembles into fibrils that orchestrate the form and function of bone, tendon, skin, and other tissues. Collagen plays roles in hemostasis, wound healing, angiogenesis, and biomineralization, and its dysfunction contributes to fibrosis, atherosclerosis, cancer metastasis, and brittle bone disease. To elucidate the type I collagen structure-function relationship, we constructed a type I collagen fibril interactome, including its functional sites and disease-associated mutations. When projected onto an X-ray diffraction model of the native collagen microfibril, data revealed a matrix interaction domain that assumes structural roles including collagen assembly, crosslinking, proteoglycan (PG) binding, and …

Lack Of Evidence For Involvement Of Tonebp And Hyperosmotic Stimulus In Induction Of Autophagy In The Nucleus Pulposus., Chao Liu, Hyowon Choi, Zariel I. Johnson, Jiwei Tian, Irving Shapiro, Makarand V Risbud

Department of Orthopaedic Surgery Faculty Papers

Nucleus pulposus (NP) cells reside in a physiologically hyperosmotic environment within the intervertebral disc. TonEBP/NFAT5 is an osmo-sensitive transcription factor that controls expression of genes critical for cell survival under hyperosmotic conditions. A recent report on NP and studies of other cell types have shown that hyperosmolarity triggers autophagy. However, little is known whether such autophagy induction occurs through TonEBP. The goal of this study was to investigate the role of TonEBP in hyperosmolarity-dependent autophagy in NP. Loss-of-function studies showed that autophagy in NP cells was not TonEBP-dependent; hyperosmolarity did not upregulate autophagy as previously reported. NP tissue of haploinsufficient …

Disc In Flames: Roles Of Tnf-Α And Il-1Β In Intervertebral Disc Degeneration., Z I Johnson, Z R Schoepflin, H Choi, I M Shapiro, M V Risbud

Department of Orthopaedic Surgery Faculty Papers

The intervertebral disc is an important mechanical structure that allows range of motion of the spinal column. Degeneration of the intervertebral disc--incited by aging, traumatic insult, genetic predisposition, or other factors--is often defined by functional and structural changes in the tissue, including excessive breakdown of the extracellular matrix, increased disc cell senescence and death, as well as compromised biomechanical function of the tissue. Intervertebral disc degeneration is strongly correlated with low back pain, which is a highly prevalent and costly condition, significantly contributing to loss in productivity and health care costs. Disc degeneration is a chronic, progressive condition, and current …

Loss Of Hif-1Α In The Notochord Results In Cell Death And Complete Disappearance Of The Nucleus Pulposus., Christophe Merceron, Laura Mangiavini, Alexander Robling, Tremika Leshan Wilson, Amato J Giaccia, Irving Shapiro, Ernestina Schipani, Makarand V Risbud

Department of Orthopaedic Surgery Faculty Papers

The intervertebral disc (IVD) is one of the largest avascular organs in vertebrates. The nucleus pulposus (NP), a highly hydrated and proteoglycan-enriched tissue, forms the inner portion of the IVD. The NP is surrounded by a multi-lamellar fibrocartilaginous structure, the annulus fibrosus (AF). This structure is covered superior and inferior side by cartilaginous endplates (CEP). The NP is a unique tissue within the IVD as it results from the differentiation of notochordal cells, whereas, AF and CEP derive from the sclerotome. The hypoxia inducible factor-1α (HIF-1α) is expressed in NP cells but its function in NP development and homeostasis is …

Does The Load-Sharing Classification Predict Ligamentous Injury, Neurological Injury, And The Need For Surgery In Patients With Thoracolumbar Burst Fractures?: Clinical Article., Kristen Radcliff, Christopher K Kepler, Todd A Rubin, Motasem Maaieh, Alan S Hilibrand, James Harrop, Jeffrey A Rihn, Todd J Albert, Alexander R Vaccaro

Department of Orthopaedic Surgery Faculty Papers

OBJECT: The load-sharing score (LSS) of vertebral body comminution is predictive of results after short-segment posterior instrumentation of thoracolumbar burst fractures. Some authors have posited that an LSS > 6 is predictive of neurological injury, ligamentous injury, and the need for surgical intervention. However, the authors of the present study hypothesized that the LSS does not predict ligamentous or neurological injury.

METHODS: The prospectively collected spinal cord injury database from a single institution was queried for thoracolumbar burst fractures. Study inclusion criteria were acute (< 24 hours) burst fractures between T-10 and L-2 with preoperative CT and MRI. Flexion-distraction injuries and pathological fractures were excluded. Four experienced spine surgeons determined the LSS and posterior ligamentous complex (PLC) integrity. Neurological status was assessed from a review of the medical records.

RESULTS: Forty-four patients were included in the study. There were 4 patients for whom all observers …

An Organ Culture System To Model Early Degenerative Changes Of The Intervertebral Disc., Ravi K Ponnappan, Dessislava Z Markova, Paul Jd Antonio, Hallie B Murray, Alexander R Vaccaro, Irving M Shapiro, D Greg Anderson, Todd J Albert, Makarand V Risbud

Department of Orthopaedic Surgery Faculty Papers

ABSTRACT: INTRODUCTION: Back pain, a significant source of morbidity in our society, is related to the degenerative changes of the intervertebral disc. At present, the treatment of disc disease consists of therapies that are aimed at symptomatic relief. This shortcoming stems in large part from our lack of understanding of the biochemical and molecular events that drive the disease process. The goal of this study is to develop a model of early disc degeneration using an organ culture. This approach is based on our previous studies that indicate that organ culture closely models molecular events that occur in vivo in …

Mast Cells And Hypoxia Drive Tissue Metaplasia And Heterotopic Ossification In Idiopathic Arthrofibrosis After Total Knee Arthroplasty., Theresa A Freeman, Javad Parvizi, Craig J Dela Valle, Marla J Steinbeck

Department of Orthopaedic Surgery Faculty Papers

ABSTRACT: BACKGROUND: Idiopathic arthrofibrosis occurs in 3-4% of patients who undergo total knee arthroplasty (TKA). However, little is known about the cellular or molecular changes involved in the onset or progression of this condition. To classify the histomorphologic changes and evaluate potential contributing factors, periarticular tissues from the knees of patients with arthrofibrosis were analyzed for fibroblast and mast cell proliferation, heterotopic ossification, cellular apoptosis, hypoxia and oxidative stress. RESULTS: The arthrofibrotic tissue was composed of dense fibroblastic regions, with limited vascularity along the outer edges. Within the fibrotic regions, elevated numbers of chymase/fibroblast growth factor (FGF)-expressing mast cells were …

Reactive Oxygen And Nitrogen Species Induce Protein And Dna Modifications Driving Arthrofibrosis Following Total Knee Arthroplasty., Theresa A Freeman, Javad Parvizi, Craig J Della Valle, Marla J Steinbeck

Department of Orthopaedic Surgery Faculty Papers

BACKGROUND: Arthrofibrosis, occurring in 3%-4% of patients following total knee arthroplasty (TKA), is a challenging condition for which there is no defined cause. The hypothesis for this study was that disregulated production of reactive oxygen species (ROS) and nitrogen species (RNS) mediates matrix protein and DNA modifications, which result in excessive fibroblastic proliferation.

RESULTS: We found increased numbers of macrophages and lymphocytes, along with elevated amounts of myeloperoxidase (MPO) in arthrofibrotic tissues when compared to control tissues. MPO expression, an enzyme that generates ROS/RNS, is usually limited to neutrophils and some macrophages, but was found by immunohistochemistry to be expressed …

Reactive Oxygen And Nitrogen Species Induce Protein And Dna Modifications Driving Arthrofibrosis Following Total Knee Arthroplasty., Theresa A Freeman, Javad Parvizi, Craig J Della Valle, Marla J Steinbeck

Department of Orthopaedic Surgery Faculty Papers

BACKGROUND: Arthrofibrosis, occurring in 3%-4% of patients following total knee arthroplasty (TKA), is a challenging condition for which there is no defined cause. The hypothesis for this study was that disregulated production of reactive oxygen species (ROS) and nitrogen species (RNS) mediates matrix protein and DNA modifications, which result in excessive fibroblastic proliferation. RESULTS: We found increased numbers of macrophages and lymphocytes, along with elevated amounts of myeloperoxidase (MPO) in arthrofibrotic tissues when compared to control tissues. MPO expression, an enzyme that generates ROS/RNS, is usually limited to neutrophils and some macrophages, but was found by immunohistochemistry to be expressed …

Isolated Polyethylene Exchange Versus Acetabular Revision For Polyethylene Wear, Camilo Restrepo, Elie Ghanem, Carrie Houssock, Mathew Austin, Javad Parvizi, William J. Hozack

Department of Orthopaedic Surgery Faculty Papers

Polyethylene wear and osteolysis are not uncommon in THA mid- and long-term. In asymptomatic patients the dilemma faced by the orthopaedic surgeon is whether to revise the cup and risk damage to the supporting columns and even pelvic discontinuity or to perform isolated polyethylene exchange and risk a high rate of postoperative recurrent instability and dislocation that will necessitate further surgery. We retrospectively reviewed 62 patients (67 hips) who underwent revision arthroplasty for polywear and osteolysis. Thirty-six hips had isolated polyethylene exchange, while 31 had full acetabular revision. The minimum followup was 2 years (mean, 2.8 years; range, 2-5 years). …

Bone Stress Injury Of The Ankle In Professional Ballet Dancers Seen On Mri., Ilan Elias, Adam C Zoga, Steven M Raikin, Judith R Peterson, Marcus P Besser, William B Morrison, Mark E Schweitzer

Department of Orthopaedic Surgery Faculty Papers

BACKGROUND: Ballet dancers have been shown to have a relatively high incidence of stress fractures of the foot and ankle. It was our objective to examine MR imaging patterns of bone marrow edema (BME) in the ankles of high performance professional ballet dancers, to evaluate clinical relevance. METHODS: MR Imaging was performed on 12 ankles of 11 active professional ballet dancers (6 female, 5 male; mean age 24 years, range 19 to 32). Individuals were imaged on a 0.2 T or 1.5 T MRI units. Images were evaluated by two musculoskeletal radiologists and one orthopaedic surgeon in consensus for location …

Concave Pit-Containing Scaffold Surfaces Improve Stem Cell-Derived Osteoblast Performance And Lead To Significant Bone Tissue Formation., Antonio Graziano, Riccardo D'Aquino, Maria Gabriella Cusella-De Angelis, Gregorio Laino, Adriano Piattelli, Maurizio Pacifici, Alfredo De Rosa, Gianpaolo Papaccio

Department of Orthopaedic Surgery Faculty Papers

BACKGROUND: Scaffold surface features are thought to be important regulators of stem cell performance and endurance in tissue engineering applications, but details about these fundamental aspects of stem cell biology remain largely unclear.

METHODOLOGY AND FINDINGS: In the present study, smooth clinical-grade lactide-coglyolic acid 85:15 (PLGA) scaffolds were carved as membranes and treated with NMP (N-metil-pyrrolidone) to create controlled subtractive pits or microcavities. Scanning electron and confocal microscopy revealed that the NMP-treated membranes contained: (i) large microcavities of 80-120 microm in diameter and 40-100 microm in depth, which we termed primary; and (ii) smaller microcavities of 10-20 microm in diameter …

Recurrent Burner Syndrome Due To Presumed Cervical Spine Osteoblastoma In A Collision Sport Athlete - A Case Report., Ilan Elias, Michael A Pahl, Adam C Zoga, Maurice L Goins, Alexander R Vaccaro

Department of Orthopaedic Surgery Faculty Papers

We present a case of a 35-year-old active rugby player presenting with a history of recurrent burner syndrome thought secondary to an osteoblastoma involving the posterior arch of the atlas. Radiographically, the lesion had features typical for a large osteoid osteoma or osteoblastoma, including osseous expansion, peripheral sclerosis and bony hypertrophy, internal lucency, and even suggestion of a central nidus. The patient subsequently underwent an en bloc resection of the posterior atlas via a standard posterior approach. The surgery revealed very good clinical results. In this report, we will discuss in detail, the presentation, treatment, and return to play recommendations …