Scholars@Duke
Nicholas Allen

Nicholas Allen

Student
Pathology

Selected Publications

Tunable Alginate-Polyvinyl Alcohol Bioinks for 3D Printing in Cartilage Tissue Engineering.

Journal Article Gels · December 14, 2024 This study investigates 3D extrusion bioinks for cartilage tissue engineering by characterizing the physical properties of 3D-printed scaffolds containing varying alginate and polyvinyl alcohol (PVA) concentrations. We systematically investigated the effec ... Full text Link to item Cite

Synovial Fluid Immune Cell Composition Following Intraarticular Fracture May Contribute to Posttraumatic Osteoarthritis.

Journal Article Int J Mol Sci · November 9, 2024 Intra-articular ankle fracture (IAF) often leads to post-traumatic osteoarthritis (PTOA), resulting in significant long-term morbidity. While previous research has focused on the inflammatory cytokines and matrix metalloproteinases within the synovial flui ... Full text Link to item Cite

Fabrication of a Novel 3D Extrusion Bioink Containing Processed Human Articular Cartilage Matrix for Cartilage Tissue Engineering.

Journal Article Bioengineering (Basel) · March 28, 2024 Cartilage damage presents a significant clinical challenge due to its intrinsic avascular nature which limits self-repair. Addressing this, our study focuses on an alginate-based bioink, integrating human articular cartilage, for cartilage tissue engineeri ... Full text Open Access Link to item Cite

A bending model for assessing relative stiffness and strength of orthopaedic fixation constructs.

Journal Article Clin Biomech (Bristol) · January 2024 BACKGROUND: The purpose of this study is to develop a simple and reproducible bending model that is compatible with a wide range of orthopaedic fixation devices and 3D printed spacers. METHODS: A robust 4-point bending model was constructed by securing saw ... Full text Link to item Cite

Time and State Legislation Have Decreased Opioid Prescribing in Elective Foot and Ankle Surgery in the United States.

Journal Article Foot Ankle Spec · October 2023 BACKGROUND: Legislation in the United States has been enacted to reduce opioid overuse and abuse in the setting of the opioid epidemic, and a notable target has been opioid overprescription. However, the impact of this legislation on elective foot and ankl ... Full text Link to item Cite

Microdrilling Resulted in Less Subchondral Bone Destruction Than a Traditional Microfracture Awl for Articular Cartilage Defect Bone Marrow Stimulation.

Journal Article Arthrosc Sports Med Rehabil · October 2023 PURPOSE: The purpose of this study was to compare bone marrow stimulation using micro-computed tomography (micro-CT) analysis of an abrasion arthroplasty technique, drilling k-wire technique, traditional microfacture awl, or a microdrill instrument for sub ... Full text Open Access Link to item Cite

Exposure of Tissue-Engineered Cartilage Analogs to Synovial Fluid Hematoma After Ankle Fracture Is Associated With Chondrocyte Death and Altered Cartilage Maintenance Gene Expression.

Journal Article Foot Ankle Int · September 2023 BACKGROUND: The first stage of fracture healing consists of hematoma formation with recruitment of proinflammatory cytokines and matrix metalloproteinases. Unfortunately, when there is an intra-articular fracture, these inflammatory mediators are not retai ... Full text Link to item Cite

The Impact of Time and State Opioid Legislation on Opioid Prescription Filling in Total Ankle Arthroplasty.

Journal Article J Foot Ankle Surg · 2023 Total ankle arthroplasty (TAA) is an increasingly utilized treatment for ankle arthritis, and opioids are commonly used as part of perioperative pain control. However, many states have enacted opioid-limiting legislation to reduce perioperative opioid pres ... Full text Link to item Cite

Three-Year Follow-Up of a Traumatic Critical-Sized Tibial Bone Defect Treated with a 3D Printed Titanium Cage: A Case Report.

Journal Article JBJS Case Connect · January 1, 2023 CASE: We report a case involving a 21-year-old woman who sustained a Grade III open pilon fracture of the left ankle during a motor vehicle accident that resulted in a 12-cm critical-sized bone defect (CSD) that was successfully treated with a three-dimens ... Full text Link to item Cite

Histologic grading correlates with inflammatory biomarkers in tibialis posterior tendon dysfunction.

Journal Article Foot Ankle Surg · December 2022 BACKGROUND: It has been theorized that tibialis posterior tendon dysfunction (TPTD) is a degenerative process unrelated to inflammation. The purpose of this study was to determine if inflammatory cytokines, matrix metalloproteases (MMPs), and glutamate wer ... Full text Link to item Cite

3D-bioprinted GelMA-gelatin-hydroxyapatite osteoblast-laden composite hydrogels for bone tissue engineering

Journal Article Bioprinting · June 1, 2022 Introduction: The treatment of large bone defects remains an area of significant challenge in orthopaedic surgery. In cases where critical-sized defects (CSDs) remain, current treatment options are underwhelming and are often fraught with complications. 3D ... Full text Cite

Outcomes of Surgical Reconstruction Using Custom 3D-Printed Porous Titanium Implants for Critical-Sized Bone Defects of the Foot and Ankle.

Journal Article Foot Ankle Int · June 2022 BACKGROUND: Treating critically sized defects (CSDs) of bone remains a significant challenge in foot and ankle surgery. Custom 3D-printed implants are being offered to a small but growing subset of patients as a salvage procedure in lieu of traditional alt ... Full text Link to item Cite

Intra-Articular Synovial Fluid With Hematoma After Ankle Fracture Promotes Cartilage Damage In Vitro Partially Attenuated by Anti-Inflammatory Agents.

Journal Article Foot Ankle Int · March 2022 BACKGROUND: Intra-articular ankle fracture (IAF) causes posttraumatic osteoarthritis (PTOA), but the exact mechanism is unknown. Proinflammatory mediators have been shown to be present in the synovial fluid fracture hematoma (SFFH) but have not been linked ... Full text Link to item Cite

In situ 3D bioprinting of musculoskeletal tissues in orthopedic surgery

Journal Article Journal of 3D Printing in Medicine · March 1, 2022 Annually, millions of Americans require some form of reconstructive surgery as the result of a traumatic injury, degenerative process or pathologic state. In the field of orthopedic surgery, the gold standard for augmenting bone, cartilage and soft tissue ... Full text Cite

Increasing age and modifiable comorbidities are associated with short-term complications after open reduction and internal fixation of ankle fractures.

Journal Article Eur J Orthop Surg Traumatol · January 2022 BACKGROUND: Ankle fractures are common orthopedic injuries with complication rates fixation of up to 40%. Limited evidence exists in the literature regarding complications in the elderly population, and moreover, these studies frequently define elderly arb ... Full text Link to item Cite

Increasing Age and Modifiable Comorbidities are Associated with Short Term Complications after ORIF of Ankle Fractures

Journal Article Foot & Ankle Orthopaedics · January 2022 Category: Trauma; Ankle Introduction/Purpose: Ankle fractures are common orthopedic injuries with complication rates fixation of up to 40%. Limited ev ... Full text Cite

Effect of surface topography on in vitro osteoblast function and mechanical performance of 3D printed titanium.

Journal Article J Biomed Mater Res A · October 2021 Critical-sized defects remain a significant challenge in orthopaedics. 3D printed scaffolds are a promising treatment but are still limited due to inconsistent osseous integration. The goal of the study is to understand how changing the surface roughness o ... Full text Open Access Link to item Cite

Histological and Inflammatory Cytokine Analysis of Osteochondral Lesions of the Talus After Failed Microfracture: Comparison With Fresh Allograft Controls.

Journal Article Orthop J Sports Med · October 2021 BACKGROUND: The most common first-line treatment of osteochondral lesions of the talus (OLTs) is microfracture. Although many patients do well with this procedure, a number fail and require reoperation. The mechanism of failure of microfracture is unknown, ... Full text Open Access Link to item Cite

Rotational Wear and Friction of Ti-6Al-4V and CoCrMo against Polyethylene and Polycarbonate Urethane

Journal Article Biotribology · June 1, 2021 Total joint replacement (TJR) is a successful procedure for millions of patients each year. Optimizing mechanical properties of bearing couples is important to increase implant longevity and improve patient outcomes. Softer viscoelastic materials offer a p ... Full text Open Access Cite

The Impact of Preoperative Mental Health and Depression on Outcomes After Total Ankle Arthroplasty.

Journal Article J Bone Joint Surg Am · January 20, 2021 BACKGROUND: Preoperative mental health and depression have been shown to negatively impact patient-reported outcome measures after a broad array of orthopaedic procedures including total ankle arthroplasty. The hypothesis for this study was that decreased ... Full text Link to item Cite

Intraoperative Fire Risk: Evaluating the 3-Minute Wait After Chlorhexidine-Alcohol Antiseptic Scrub.

Journal Article J Orthop Trauma · January 1, 2021 OBJECTIVE: We sought to determine the flammability of the skin at different time intervals after chlorhexidine-alcohol antiseptic scrub application, to provide evidence for hospital protocols recommending a 3-minute drying time. METHODS: Swine feet, which ... Full text Link to item Cite

Clinical Outcomes of 3D Printed Titanium Cage Implantation for Foot and Ankle Surgery

Journal Article Foot & Ankle Orthopaedics · October 1, 2020 Category Ankle; Trauma Introduction/Purpose: Critical Sized Defects (CSD) defined as bone loss greater than 1-2 cm in length or greater than 50% loss ... Full text Cite

Influence of Topography on 3D printed Titanium Foot and Ankle Implants

Journal Article Foot & Ankle Orthopaedics · October 1, 2020 Category: Basic Sciences/Biologics; Ankle; Trauma Introduction/Purpose Foot and ankle etiologies such as traumatic fractures, Charcot Arthropathy, non ... Full text Cite

The Intra-Articular Hematoma Immediately after Ankle Fracture Causes Cartilage Damage That is Partially Attenuated by Anti-Inflammatory Agents

Journal Article Foot & Ankle Orthopaedics · April 1, 2020 Category: Ankle Arthritis; Basic Sciences/Biologics Introduction/Purpose: Post-traumatic osteoarthritis (PTOA) is a frequent cause of disability. The ... Full text Cite