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Glatt V, Bartnikowski N, Bartnikowski M, Aguilar L, Schuetz M, Tetsworth K. Intramedullary implant stability affects patterns of fracture healing in mice with morphologically different bone phenotypes. Bone 2024; 179:116978. [PMID: 37993038 DOI: 10.1016/j.bone.2023.116978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/18/2023] [Accepted: 11/19/2023] [Indexed: 11/24/2023]
Abstract
Almost all prior mouse fracture healing models have used needles or K-wires for fixation, unwittingly providing inadequate mechanical stability during the healing process. Our contention is that the reported outcomes have predominantly reflected this instability, rather than the impact of diverse biological conditions, pharmacologic interventions, exogenous growth factors, or genetic considerations. This important issue becomes obvious upon a critical review of the literature. Therefore, the primary aim of this study was to demonstrate the significance of mouse-specific implants designed to provide both axial and torsional stability (Screw and IM Nail) compared to conventional pins (Needle and K-wires), even when used in mice with differently sized marrow canals and diverse genetic backgrounds. B6 (large medullary canal), DBA, and C3H (smaller medullary canals) mice were employed, all of which have different bone morphologies. Closed femoral fractures were created and stabilized with intramedullary implants that provide different mechanical conditions during the healing process. The most important finding of this study was that appropriately designed mouse-specific implants, providing both axial and torsional stability, had the greatest influence on bone healing outcomes regardless of the different bone morphologies encountered. For instance, unstable implants in the B6 strain (largest medullary canal) resulted in significantly greater callus, with a fracture region mainly comprising trabecular bone along with the presence of cartilage 28 days after surgery. The DBA and C3H strains (with smaller medullary canals) instead formed significantly less callus, and only had a small amount of intracortical trabeculation remaining. Moreover, with more stable fracture fixation a higher BV/TV was observed and cortices were largely restored to their original dimensions and structure, indicating an accelerated healing and remodeling process. These observations reveal that the diaphyseal cortical thickness, influenced by the genetic background of each strain, played a pivotal role in determining the amount of bone formation in response to the fracture. These findings are highly important, indicating the rate and type of tissue formed is a direct result of mechanical instability, and this most likely would mask the true contribution of the tested genes, genetic backgrounds, or various therapeutic agents administered during the bone healing process.
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Affiliation(s)
- Vaida Glatt
- Department of Orthopaedic Surgery, University of Texas Health Science Center, San Antonio, TX, United States of America; Sam and Ann Barshop Institute for Longevity and Aging Studies at the University of Texas Health Science Center, San Antonio, TX, United States of America; Queensland University of Technology, Brisbane, Australia; Orthopaedic Research Centre of Australia, Brisbane, Australia.
| | | | | | - Leonardo Aguilar
- Department of Orthopaedic Surgery, University of Texas Health Science Center, San Antonio, TX, United States of America; Sam and Ann Barshop Institute for Longevity and Aging Studies at the University of Texas Health Science Center, San Antonio, TX, United States of America
| | | | - Kevin Tetsworth
- Department of Orthopaedic Surgery, The Royal Brisbane and Women's Hospital, Brisbane, Australia; Orthopaedic Research Centre of Australia, Brisbane, Australia
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Cao Y, Kalajzic I, Matthews BG. CD51 labels periosteal injury-responsive osteoprogenitors. Front Physiol 2023; 14:1231352. [PMID: 37731543 PMCID: PMC10507171 DOI: 10.3389/fphys.2023.1231352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/22/2023] [Indexed: 09/22/2023] Open
Abstract
The periosteum is a critical source of skeletal stem and progenitor cells (SSPCs) that form callus tissue in response to injury. There is yet to be a consensus on how to identify SSPCs in the adult periosteum. The aim of this study was to understand how potential murine periosteal SSPC populations behave in vivo and in response to injury. We evaluated the in vivo differentiation potential of Sca1-CD51+ and Sca1+CD51+ cells following transplantation. In vitro, the Sca1+CD51+ population appears to be more primitive multipotent cells, but after transplantation, Sca1-CD51+ cells showed superior engraftment, expansion, and differentiation into chondrocytes and osteoblasts. Despite representing a clear population with flow cytometry, we identified very few Sca1+CD51+ cells histologically. Using a periosteal scratch injury model, we successfully mimicked the endochondral-like healing process seen in unstable fractures, including the expansion and osteochondral differentiation of αSMA+ cells following injury. CD51+ cells were present in the cambium layer of resting periosteum and expanded following injury. Sca1+CD51- cells were mainly localized in the outer periosteal layer. We found that injury increased colony-forming unit fibroblast (CFU-F) formation in the periosteum and led to rapid expansion of CD90+ cells. Several other populations, including Sca1-CD51+ and CD34+ cells, were expanded by day 7. Mice with enhanced fracture healing due to elevated Notch signaling mediated by NICD1 overexpression showed significant expansion of CD51+ and CD34hi cells in the early stages of healing, suggesting these populations contribute to more rapid healing. In conclusion, we demonstrate that periosteal injury leads to the expansion of various SSPC populations, but further studies are required to confirm their lineage hierarchy in the adult skeletal system. Our data indicate that CD51+ skeletal progenitor cells are injury-responsive and show good engraftment and differentiation potential upon transplantation.
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Affiliation(s)
- Ye Cao
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Ivo Kalajzic
- Center for Regenerative Medicine and Skeletal Development, School of Dental Medicine, UConn Health, Farmington, CT, United States
| | - Brya G. Matthews
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
- Center for Regenerative Medicine and Skeletal Development, School of Dental Medicine, UConn Health, Farmington, CT, United States
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Rosell-Pradas J, Redondo-Trasobares B, Sarasa-Roca M, Albareda-Albareda J, Puértolas-Broto S, Herrera-Rodríguez A, Gracia-Villa L. Influence of plate size and screw distribution on the biomechanical behaviour of osteosynthesis by means of lateral plates in femoral fractures. Injury 2023; 54:395-404. [PMID: 36528423 DOI: 10.1016/j.injury.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022]
Abstract
Distal femoral fractures are fractures associated with high rates of morbidity and mortality, affecting to three different groups of individuals: younger people suffering high-energy trauma, elderly people with fragile bones and people with periprosthetic fractures around previous total knee arthroplasty. They have been classically treated with conventional plates and intramedullary nails and more recently with locked plates that have increased their indications to more types of fractures. The main objective of the present work is the biomechanical study, by means of finite element simulation, of the stability achieved in the osteosynthesis of femoral fractures in zones 4 and 5 of Wiss, by using locked plates with different plate lengths and different screw configurations, and analysing the effect of screw proximity to the fracture site. A three dimensional (3D) finite element model of the femur from 55-year-old male donor was developed, and then a stability analysis was performed for the fixation provided by Osteosynthesis System LOQTEC® Lateral Distal Femur Plate in two different fracture zones corresponding to the zones 4 and 5 according to the Wiss fracture classification. The study was focused on the immediately post-operative stage, without any biological healing process. The obtained results show that more stable osteosyntheses were obtained by using shorter plates. In the cases of longer plates, it results more convenient disposing screws in a way that the upper ones are closer to fracture site. The obtained results can support surgeons to understand the biomechanics of fracture stability, and then to guide them towards the more appropriate osteosynthesis depending on the fracture type and location.
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Affiliation(s)
- J Rosell-Pradas
- Department of Mechanical Engineering, University of Zaragoza, Zaragoza, Spain
| | - B Redondo-Trasobares
- Department of Orthopaedic Surgery and Traumatology, Lozano Blesa University Hospital, Zaragoza, Spain; Aragón Health Research Institute, Zaragoza, Spain
| | - M Sarasa-Roca
- Department of Orthopaedic Surgery and Traumatology, Lozano Blesa University Hospital, Zaragoza, Spain; Aragón Health Research Institute, Zaragoza, Spain
| | - J Albareda-Albareda
- Department of Orthopaedic Surgery and Traumatology, Lozano Blesa University Hospital, Zaragoza, Spain; Aragón Health Research Institute, Zaragoza, Spain; Department of Surgery, University of Zaragoza, Zaragoza, Spain.
| | - S Puértolas-Broto
- Department of Mechanical Engineering, University of Zaragoza, Zaragoza, Spain; Aragón Institute for Engineering Research, Zaragoza, Spain
| | | | - L Gracia-Villa
- Department of Mechanical Engineering, University of Zaragoza, Zaragoza, Spain; Aragón Institute for Engineering Research, Zaragoza, Spain
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The role of hypertrophic chondrocytes in regulation of the cartilage-to-bone transition in fracture healing. Bone Rep 2022; 17:101616. [PMID: 36105852 PMCID: PMC9465425 DOI: 10.1016/j.bonr.2022.101616] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/05/2022] [Accepted: 06/07/2022] [Indexed: 11/23/2022] Open
Abstract
Endochondral bone formation is an important pathway in fracture healing, involving the formation of a cartilaginous soft callus and the process of cartilage-to-bone transition. Failure or delay in the cartilage-to-bone transition causes an impaired bony union such as nonunion or delayed union. During the healing process, multiple types of cells including chondrocytes, osteoprogenitors, osteoblasts, and endothelial cells coexist in the callus, and inevitably crosstalk with each other. Hypertrophic chondrocytes located between soft cartilaginous callus and bony hard callus mediate the crosstalk regulating cell-matrix degradation, vascularization, osteoclast recruitment, and osteoblast differentiation in autocrine and paracrine manners. Furthermore, hypertrophic chondrocytes can become osteoprogenitors and osteoblasts, and directly contribute to woven bone formation. In this review, we focus on the roles of hypertrophic chondrocytes in fracture healing and dissect the intermingled crosstalk in fracture callus during the cartilage-to-bone transition.
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Glatt V, Samchukov M, Cherkashin A, Iobst C. Reverse Dynamization Accelerates Bone-Healing in a Large-Animal Osteotomy Model. J Bone Joint Surg Am 2021; 103:257-263. [PMID: 33315696 DOI: 10.2106/jbjs.20.00380] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Reverse dynamization is a mechanical manipulation regimen designed to accelerate bone-healing and remodeling. It is based on the hypothesis that a fracture that is initially stabilized less rigidly allows micromotion to encourage initial cartilaginous callus formation. Once substantial callus has formed, the stabilization should then be converted to a rigid configuration to prevent the disruption of neovascularization. The aim of the present study was to investigate whether bone-healing can be accelerated using a regimen of reverse dynamization in a large-animal osteotomy model. METHODS Transverse 2-mm tibial osteotomies were created in 18 goats, stabilized using circular external fixation, and divided into groups of 6 goats each: static fixation (rigid fixation), dynamic fixation (continuous micromotion using dynamizers), and reverse dynamization (initial micromotion using dynamizers followed by rigid fixation at 3 weeks postoperatively). Healing was assessed with the use of radiographs, micro-computed tomography, and mechanical testing. RESULTS Radiographic evaluation showed earlier and more robust callus formation in the dynamic fixation and reverse dynamization groups compared with the static fixation group. After 8 weeks of treatment, the reverse dynamization group had reduced callus size, less bone volume, higher bone mineral density, and no evidence of radiolucent lines compared with the static fixation and dynamic fixation groups. This appearance is characteristic of advanced remodeling, returning closest to the values of intact bone. Moreover, the tibiae in the reverse dynamization group were significantly stronger in torsion compared with those in the static fixation and dynamic fixation groups. CONCLUSIONS These findings confirmed that tibial osteotomies under reverse dynamization healed faster, healed objectively better, and were considerably stronger, all suggesting an accelerated healing and remodeling process. CLINICAL RELEVANCE This study demonstrates that the concept of reverse dynamization challenges the current understanding regarding the optimal fixation stability necessary to maximize the regenerative capacity of bone-healing. When reverse dynamization is employed in the clinical setting, it may be able to improve the treatment of fractures by reducing the time to union and potentially lowering the risk of delayed union and nonunion.
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Affiliation(s)
- Vaida Glatt
- Department of Orthopedic Surgery, University of Texas Health Science Center, San Antonio, Texas
| | - Mikhail Samchukov
- The Center for Excellence in Limb Lengthening & Reconstruction, Texas Scottish Rite Hospital for Children, Dallas, Texas.,Department of Orthopedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Alexander Cherkashin
- The Center for Excellence in Limb Lengthening & Reconstruction, Texas Scottish Rite Hospital for Children, Dallas, Texas.,Department of Orthopedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Christopher Iobst
- Center for Limb Lengthening and Reconstruction, Nationwide Children's Hospital, Columbus, Ohio
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Wilson CJ, Epari DR, Ernst M, Arens D, Zeiter S, Windolf M. Morphology of bony callus growth in healing of a sheep tibial osteotomy. Injury 2021; 52:66-70. [PMID: 33268079 DOI: 10.1016/j.injury.2020.10.083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/09/2020] [Accepted: 10/17/2020] [Indexed: 02/02/2023]
Abstract
Long bone fractures typically heal via formation of an external callus, which helps stabilise the bone fragments. Callus composition and morphology influence the mechanical environment, which in turn regulates the progression of healing. Therefore characterising callus development over time is crucial in understanding this mechanobiological regulation. Although bony callus is often assumed to grow towards the fracture from either side, this is not consistent with observations from large animal studies and clinical cases. Therefore, we sought to quantify the morphology of bony callus over time in a large animal model. Sheep tibiae were x-rayed weekly over eight weeks following an osteotomy (n=5), with fixation allowing up to 10% axial displacement under normal weight-bearing. After scaling radiographs by known landmarks and normalising greyscales, bony callus boundaries were defined by manual segmentation. The lateral callus area and coordinates of its centroid were calculated from each image. The external callus initially formed adjacent to the osteotomy site. Over the first four weeks, callus growth from its outer surfaces was characterised by its centre of area moving outwards and away from the osteotomy, on both proximal and distal fragments. Subsequent weeks showed consolidation and resorption from the outer surface of the callus. Our approach allowed bony callus development to be tracked in individuals throughout healing. Contrary to the view that periosteal bone formation originates distant from the fracture, our data showed bony callus adjacent to the defect from early stages, followed by approximately concentric growth. This discrepancy highlights the need for data specific to experimental conditions, and particularly early stages of healing, for evaluating theoretical models of mechanical regulation.
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Affiliation(s)
- Cameron J Wilson
- Institute of Health and Biomedical Innovation and Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia.
| | - Devakara R Epari
- Institute of Health and Biomedical Innovation and Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia.
| | - Manuela Ernst
- AO Research Institute, Clavadelerstrasse 8, 7270 Davos, Switzerland.
| | - Daniel Arens
- AO Research Institute, Clavadelerstrasse 8, 7270 Davos, Switzerland.
| | - Stephan Zeiter
- AO Research Institute, Clavadelerstrasse 8, 7270 Davos, Switzerland.
| | - Markus Windolf
- Institute of Health and Biomedical Innovation and Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Queensland 4001, Australia; AO Research Institute, Clavadelerstrasse 8, 7270 Davos, Switzerland.
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Kamalitdinov TB, Fujino K, Shetye SS, Jiang X, Ye Y, Rodriguez AB, Kuntz AF, Zgonis MH, Dyment NA. Amplifying Bone Marrow Progenitors Expressing α-Smooth Muscle Actin Produce Zonal Insertion Sites During Tendon-to-Bone Repair. J Orthop Res 2020; 38:105-116. [PMID: 31228280 PMCID: PMC6917878 DOI: 10.1002/jor.24395] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 06/06/2019] [Indexed: 02/04/2023]
Abstract
Traditional tendon-to-bone repair where the tendon is reattached to bone via suture anchors often results in disorganized scar production rather than the formation of a zonal insertion. In contrast, ligament reconstructions where tendon grafts are passed through bone tunnels can yield zonal tendon-to-bone attachments between the graft and adjacent bone. Therefore, ligament reconstructions can be used to study mechanisms that regulate zonal tendon-to-bone repair in the adult. Anterior cruciate ligament (ACL) reconstructions are one of the most common reconstruction procedures and while we know that cells from outside the graft produce the attachments, we have not yet established specific cell populations that give rise to this tissue. To address this knowledge gap, we performed ACL reconstructions in lineage tracing mice where α-smooth muscle actin (αSMACreERT2) was used to label αSMA-expressing progenitors within the bone marrow that produced zonal attachments. Expression of αSMA was increased during early stages of the repair process such that the contribution of SMA-labeled cells to the tunnel integration was highest when tamoxifen was delivered in the first week post-surgery. The zonal attachments shared features with normal entheses, including tidemarks oriented perpendicularly to collagen fibers, Col1a1-expressing cells, alkaline phosphatase activity, and proteoglycan-rich staining. Finally, the integration strength increased with time, requiring 112% greater force to remove the graft from the tunnel at 28 days compared with 14 days post-surgery. Future studies will target these progenitor cells to define the pathways that regulate zonal tendon-to-bone repair in the adult. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:105-116, 2020.
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Affiliation(s)
- Timur B. Kamalitdinov
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Keitaro Fujino
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA,Department of Orthopedic Surgery, Osaka Medical College, Osaka, Japan
| | - Snehal S. Shetye
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Xi Jiang
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Yaping Ye
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Ashley B. Rodriguez
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew F. Kuntz
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Miltiadis H. Zgonis
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Nathaniel A. Dyment
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
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Das V, Kroin JS, Moric M, McCarthy RJ, Buvanendran A. Early Treatment With Metformin in a Mice Model of Complex Regional Pain Syndrome Reduces Pain and Edema. Anesth Analg 2019; 130:525-534. [PMID: 30801357 DOI: 10.1213/ane.0000000000004057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Metformin, an adenosine monophosphate (AMP)-activated protein kinase activator, as well as a common drug for type 2 diabetes, has previously been shown to decrease mechanical allodynia in mice with neuropathic pain. The objective of this study is to determine if treatment with metformin during the first 3 weeks after fracture would produce a long-term decrease in mechanical allodynia and improve a complex behavioral task (burrowing) in a mouse tibia fracture model with signs of complex regional pain syndrome. METHODS Mice were allocated into distal tibia fracture or nonfracture groups (n = 12 per group). The fracture was stabilized with intramedullary pinning and external casting for 21 days. Animals were then randomized into 4 groups (n = 6 per group): (1) fracture, metformin treated, (2) fracture, saline treated, (3) nonfracture, metformin treated, and (4) nonfracture, saline treated. Mice received daily intraperitoneal injections of metformin 200 mg/kg or saline between days 14 and 21. After cast removal, von Frey force withdrawal (every 3 days) and burrowing (every 7 days) were tested between 25 and 56 days. Paw width was measured for 14 days after cast removal. AMP-activated protein kinase downregulation at 4 weeks after tibia fracture in the dorsal root ganglia was examined by immunohistochemistry for changes in the AMP-activated protein kinase pathway. RESULTS Metformin injections elevated von Frey thresholds (reduced mechanical allodynia) in complex regional pain syndrome mice versus saline-treated fracture mice between days 25 and 56 (difference of mean area under the curve, 42.5 g·d; 95% CI of the difference, 21.0-63.9; P < .001). Metformin also reversed burrowing deficits compared to saline-treated tibial fracture mice (difference of mean area under the curve, 546 g·d; 95% CI of the difference, 68-1024; P < .022). Paw width (edema) was reduced in metformin-treated fracture mice. After tibia fracture, AMP-activated protein kinase was downregulated in dorsal root ganglia neurons, and mechanistic target of rapamycin, ribosomal S6 protein, and eukaryotic initiation factor 2α were upregulated. CONCLUSIONS The important finding of this study was that early treatment with metformin reduces mechanical allodynia in a complex regional pain syndrome model in mice. Our findings suggest that AMP-activated protein kinase activators may be a viable therapeutic target for the treatment of pain associated with complex regional pain syndrome.
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Affiliation(s)
- Vaskar Das
- From the Department of Anesthesiology, Rush University Medical Center, Chicago, Illinois
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Wenger D, Andersson S. Low risk of nonunion with lateral locked plating of distal femoral fractures-A retrospective study of 191 consecutive patients. Injury 2019; 50:448-452. [PMID: 30401542 DOI: 10.1016/j.injury.2018.10.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/18/2018] [Accepted: 10/28/2018] [Indexed: 02/02/2023]
Abstract
INTRODUCTION The reported rate of nonunion of distal femoral fractures varies in the literature. Several risk factors for nonunion following lateral locked plating (LLP) have been described. We aimed to study the rate of nonunion, and risk factors thereof, in a Swedish population where fragility fractures are common. A secondary aim was to study risk factors for reoperation for any cause. PATIENTS AND METHODS We retrospectively reviewed the hospital files and radiographs of all adult patients admitted to our institution with a distal femoral fracture, from 2004 through 2013. In cases treated with LLP, medical comorbidities, fracture characteristics and implant characteristics were analysed as potential risk factors for nonunion, defined as any surgical intervention to improve healing. RESULTS There were 8 cases (4%, 95%CI: 1.8-8.1%) of nonunion in 191 fractures treated with LLP. Patients with nonunion were younger: 62 vs. 81 years (p = 0.009) and more commonly had open fractures: 38% vs. 9% (p = 0.034). No patient 80 years or older had a surgical intervention for nonunion. Lower age was independently associated with reoperation for any cause, but not for nonunion. DISCUSSION The low rate of nonunion in this study is probably due to the fact that we present data from a complete cohort from a geographic catchment area. Referral centres with a high proportion of young patients with high-energy injuries, may be better suited for studies on risk factors for nonunion, due to higher statistical power. However, results from such institutions may not be generalizable to the more common low-energy fractures.
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Affiliation(s)
- Daniel Wenger
- Dept. of Orthopaedics, Skåne University Hospital, Malmö, Sweden; Lund University, Lund, Sweden.
| | - Sanet Andersson
- Dept. of Emergency Medicine, Skåne University Hospital, Malmö, Sweden
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10
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Kroin JS, Das V, Moric M, Buvanendran A. Efficacy of the ketamine metabolite (2R,6R)-hydroxynorketamine in mice models of pain. Reg Anesth Pain Med 2019; 44:111-117. [DOI: 10.1136/rapm-2018-000013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/31/2018] [Accepted: 06/06/2018] [Indexed: 01/01/2023]
Abstract
Background and objectivesKetamine has been shown to reduce chronic pain; however, the adverse events associated with ketamine makes it challenging for use outside of the perioperative setting. The ketamine metabolite (2R,6R)-hydroxynorketamine ((2R,6R)-HNK) has a therapeutic effect in mice models of depression, with minimal side effects. The objective of this study is to determine if (2R,6R)-HNK has efficacy in both acute and chronic mouse pain models.MethodsMice were tested in three pain models: nerve-injury neuropathic pain, tibia fracture complex regional pain syndrome type-1 (CRPS1) pain, and plantar incision postoperative pain. Once mechanical allodynia had developed, systemic (2R,6R)-HNK or ketamine was administered as a bolus injection and compared with saline control in relieving allodynia.ResultsIn all three models, 10 mg/kg ketamine failed to produce sustained analgesia. In the neuropathic pain model, a single intraperitoneal injection of 10 mg/kg (2R,6R)-HNK elevated von Frey thresholds over a time period of 1–24hours compared with saline (F=121.6, p<0.0001), and three daily (2R,6R)-HNK injections elevated von Frey thresholds for 3 days compared with saline (F=33.4, p=0.0002). In the CRPS1 model, three (2R,6R)-HNK injections elevated von Frey thresholds for 3 days and then an additional 4 days compared with saline (F=116.1, p<0.0001). In the postoperative pain model, three (2R,6R)-HNK injections elevated von Frey thresholds for 3 days and then an additional 5 days compared with saline (F=60.6, p<0.0001).ConclusionsThis study demonstrates that (2R,6R)-HNK is superior to ketamine in reducing mechanical allodynia in acute and chronic pain models and suggests it may be a new non-opioid drug for future therapeutic studies.
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11
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Zondervan RL, Vorce M, Servadio N, Hankenson KD. Fracture Apparatus Design and Protocol Optimization for Closed-stabilized Fractures in Rodents. J Vis Exp 2018. [PMID: 30176013 DOI: 10.3791/58186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The reliable generation of consistent stabilized fractures in animal models is essential for understanding the biology of bone regeneration and developing therapeutics and devices. However, available injury models are plagued by inconsistency resulting in wasted animals and resources and imperfect data. To address this problem of fracture heterogeneity, the purpose of the method described herein is to optimize fracture generation parameters specific to each animal and yield a consistent fracture location and pattern. This protocol accounts for variations in bone size and morphology that may exist between mouse strains and can be adapted to generate consistent fractures in other species, such as rat. Additionally, a cost-effective, adjustable fracture apparatus is described. Compared to current stabilized fracture techniques, the optimization protocol and new fracture apparatus demonstrate increased consistency in stabilized fracture patterns and locations. Using optimized parameters specific to the sample type, the described protocol increases the precision of induced traumas, minimizing the fracture heterogeneity typically observed in closed-fracture generation procedures.
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Affiliation(s)
- Robert L Zondervan
- College of Osteopathic Medicine, Michigan State University; Department of Orthopaedic Surgery, University of Michigan Medical School
| | - Mitch Vorce
- Lymann Briggs College, Michigan State University
| | | | - Kurt D Hankenson
- Department of Orthopaedic Surgery, University of Michigan Medical School;
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12
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Stiers PJ, van Gastel N, Moermans K, Stockmans I, Carmeliet G. Regulatory elements driving the expression of skeletal lineage reporters differ during bone development and adulthood. Bone 2017; 105:154-162. [PMID: 28863946 DOI: 10.1016/j.bone.2017.08.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/28/2017] [Accepted: 08/28/2017] [Indexed: 01/06/2023]
Abstract
To improve bone healing or regeneration more insight in the fate and role of the different skeletal cell types is required. Mouse models for fate mapping and lineage tracing of skeletal cells, using stage-specific promoters, have advanced our understanding of bone development, a process that is largely recapitulated during bone repair. However, validation of these models is often only performed during development, whereas proof of the activity and specificity of the used promoters during the bone regenerative process is limited. Here, we show that the regulatory elements of the 6kb collagen type II promoter are not adequate to drive gene expression during bone repair. Similarly, the 2.3kb promoter of collagen type I lacks activity in adult mice, but the 3.2kb promoter is suitable. Furthermore, Cre-mediated fate mapping allows the visualization of progeny, but this label retention may hinder to distinguish these cells from ones with active expression of the marker at later time points. Together, our results show that the lineage-specific regulatory elements driving gene expression during bone development differ from those required later in life and during bone repair, and justify validation of lineage-specific cell tracing and gene silencing strategies during fracture healing and bone regenerative applications.
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Affiliation(s)
- Pieter-Jan Stiers
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium
| | - Nick van Gastel
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium
| | - Karen Moermans
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium
| | - Ingrid Stockmans
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium
| | - Geert Carmeliet
- Laboratory of Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium.
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13
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Roeder E, Matthews BG, Kalajzic I. Visual reporters for study of the osteoblast lineage. Bone 2016; 92:189-195. [PMID: 27616604 PMCID: PMC5056847 DOI: 10.1016/j.bone.2016.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 12/24/2022]
Abstract
Advancing our understanding of osteoblast biology and differentiation is critical to elucidate the pathological mechanisms responsible for skeletal diseases such as osteoporosis. Histology and histomorphometry, the classical methods to study osteoblast biology, identify osteoblasts based on their location and morphology and ability to mineralize matrix, but do not clearly define their stage of differentiation. Introduction of visual transgenes into the cells of osteoblast lineage has revolutionized the field and resulted in a paradigm shift that allowed for specific identification and isolation of subpopulations within the osteoblast lineage. Knowledge acquired from the studies based on GFP transgenes has allowed for more precise interpretation of studies analyzing targeted overexpression or deletion of genes in the osteoblast lineage. Here, we provide a condensed overview of the currently available promoter-fluorescent reporter transgenic mice that have been generated and evaluated to varying extents. We cover different stages of the lineage as transgenes have been utilized to identify osteoprogenitors, pre-osteoblasts, osteoblasts, or osteocytes. We show that each of these promoters present with advantages and disadvantages. The studies based on the use of these reporter mice have improved our understanding of bone biology. They constitute attractive models to target osteoblasts and help to understand their cell biology.
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Affiliation(s)
- Emilie Roeder
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Brya G Matthews
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT 06030, USA; Department of Pathophysiology, University of Osijek, Osijek, Croatia.
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14
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Yoshida R, Alaee F, Dyrna F, Kronenberg MS, Maye P, Kalajzic I, Rowe DW, Mazzocca AD, Dyment NA. Murine supraspinatus tendon injury model to identify the cellular origins of rotator cuff healing. Connect Tissue Res 2016; 57:507-515. [PMID: 27184388 PMCID: PMC5149426 DOI: 10.1080/03008207.2016.1189910] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
UNLABELLED Purpose of this study: To elucidate the origin of cell populations that contribute to rotator cuff healing, we developed a mouse surgical model where a full-thickness, central detachment is created in the supraspinatus. MATERIALS AND METHODS Three different inducible Cre transgenic mice with Ai9-tdTomato reporter expression (PRG4-9, αSMA-9, and AGC-9) were used to label different cell populations in the shoulder. The defect was created surgically in the supraspinatus. The mice were injected with tamoxifen at surgery to label the cells and sacrificed at 1, 2, and 5 weeks postoperatively. Frozen sections were fluorescently imaged then stained with Toluidine Blue and re-imaged. RESULTS Three notable changes were apparent postoperatively. (1) A long thin layer of tissue formed on the bursal side overlying the supraspinatus tendon. (2) The tendon proximal to the defect initially became hypercellular and disorganized. (3) The distal stump at the insertion underwent minimal remodeling. In the uninjured shoulder, tdTomato expression was seen in the tendon midsubstance and paratenon cell on the bursal side in PRG4-9, in paratenon, blood vessels, and periosteum of acromion in SMA-9, and in articular cartilage, unmineralized fibrocartilage of supraspinatus enthesis, and acromioclavicular joint in AGC-9 mice. In the injured PRG4-9 and SMA-9 mice, the healing tissues contained an abundant number of tdTomato+ cells, while minimal contribution of tdTomato+ cells was seen in AGC-9 mice. CONCLUSIONS The study supports the importance of the bursal side of the tendon to rotator cuff healing and PRG4 and αSMA may be markers for these progenitor cells.
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Affiliation(s)
- Ryu Yoshida
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT
| | - Farhang Alaee
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT
| | - Felix Dyrna
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT
| | - Mark S. Kronenberg
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT
| | - Peter Maye
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT
| | - David W Rowe
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT
| | - Augustus D. Mazzocca
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT
| | - Nathaniel A Dyment
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT
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15
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Dyment NA, Jiang X, Chen L, Hong SH, Adams DJ, Ackert-Bicknell C, Shin DG, Rowe DW. High-Throughput, Multi-Image Cryohistology of Mineralized Tissues. J Vis Exp 2016. [PMID: 27684089 DOI: 10.3791/54468] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
There is an increasing need for efficient phenotyping and histopathology of a variety of tissues. This phenotyping need is evident with the ambitious projects to disrupt every gene in the mouse genome. The research community needs rapid and inexpensive means to phenotype tissues via histology. Histological analyses of skeletal tissues are often time consuming and semi-quantitative at best, regularly requiring subjective interpretation of slides from trained individuals. Here, we present a cryohistological paradigm for efficient and inexpensive phenotyping of mineralized tissues. First, we present a novel method of tape-stabilized cryosectioning that preserves the morphology of mineralized tissues. These sections are then adhered rigidly to glass slides and imaged repeatedly over several rounds of staining. The resultant images are then aligned either manually or via computer software to yield composite stacks of several layered images. The protocol allows for co-localization of numerous molecular signals to specific cells within a given section. In addition, these fluorescent signals can be quantified objectively via computer software. This protocol overcomes many of the shortcomings associated with histology of mineralized tissues and can serve as a platform for high-throughput, high-content phenotyping of musculoskeletal tissues moving forward.
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Affiliation(s)
- Nathaniel A Dyment
- Department of Reconstructive Sciences, University of Connecticut Health Center;
| | - Xi Jiang
- Department of Reconstructive Sciences, University of Connecticut Health Center
| | - Li Chen
- Department of Reconstructive Sciences, University of Connecticut Health Center
| | - Seung-Hyun Hong
- Department of Computer Science and Engineering, University of Connecticut
| | - Douglas J Adams
- Department of Orthopaedic Surgery, University of Connecticut Health Center
| | | | - Dong-Guk Shin
- Department of Computer Science and Engineering, University of Connecticut
| | - David W Rowe
- Department of Reconstructive Sciences, University of Connecticut Health Center;
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16
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Glatt V, Bartnikowski N, Quirk N, Schuetz M, Evans C. Reverse Dynamization: Influence of Fixator Stiffness on the Mode and Efficiency of Large-Bone-Defect Healing at Different Doses of rhBMP-2. J Bone Joint Surg Am 2016; 98:677-87. [PMID: 27098327 PMCID: PMC4832588 DOI: 10.2106/jbjs.15.01027] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Reverse dynamization is a technology for enhancing the healing of osseous defects. With use of an external fixator, the axial stiffness across the defect is initially set low and subsequently increased. The purpose of the study described in this paper was to explore the efficacy of reverse dynamization under different conditions. METHODS Rat femoral defects were stabilized with external fixators that allowed the stiffness to be modulated on living animals. Recombinant human bone morphogenetic protein-2 (rhBMP-2) was implanted into the defects on a collagen sponge. Following a dose-response experiment, 5.5 μg of rhBMP-2 was placed into the defect under conditions of very low (25.4-N/mm), low (114-N/mm), medium (185-N/mm), or high (254-N/mm) stiffness. Reverse dynamization was evaluated with 2 different starting stiffnesses: low (114 N/mm) and very low (25.4 N/mm). In both cases, high stiffness (254 N/mm) was imposed after 2 weeks. Healing was assessed with radiographs, micro-computed tomography (μCT), histological analysis, and mechanical testing. RESULTS In the absence of dynamization, the medium-stiffness fixators provided the best healing. Reverse dynamization starting with very low stiffness was detrimental to healing. However, with low initial stiffness, reverse dynamization considerably improved healing with minimal residual cartilage, enhanced cortication, increased mechanical strength, and smaller callus. Histological analysis suggested that, in all cases, healing provoked by rhBMP-2 occurred by endochondral ossification. CONCLUSIONS These data confirm the potential utility of reverse dynamization as a way of improving bone healing but indicate that the stiffness parameters need to be selected carefully. CLINICAL RELEVANCE Reverse dynamization may reduce the amount of rhBMP-2 needed to induce healing of recalcitrant osseous lesions, reduce the time to union, and decrease the need for prolonged external fixation.
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Affiliation(s)
- Vaida Glatt
- Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Queensland, Australia,E-mail address for V. Glatt:
| | - Nicole Bartnikowski
- Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Queensland, Australia
| | - Nicholas Quirk
- Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Queensland, Australia,Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Michael Schuetz
- Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Queensland, Australia,Princess Alexandra Hospital, Brisbane, Queensland, Australia
| | - Christopher Evans
- Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
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17
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Elkins J, Marsh JL, Lujan T, Peindl R, Kellam J, Anderson DD, Lack W. Motion Predicts Clinical Callus Formation: Construct-Specific Finite Element Analysis of Supracondylar Femoral Fractures. J Bone Joint Surg Am 2016; 98:276-84. [PMID: 26888675 PMCID: PMC5141368 DOI: 10.2106/jbjs.o.00684] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Mechanotransduction is theorized to influence fracture-healing, but optimal fracture-site motion is poorly defined. We hypothesized that three-dimensional (3-D) fracture-site motion as estimated by finite element (FE) analysis would influence callus formation for a clinical series of supracondylar femoral fractures treated with locking-plate fixation. METHODS Construct-specific FE modeling simulated 3-D fracture-site motion for sixty-six supracondylar femoral fractures (OTA/AO classification of 33A or 33C) treated at a single institution. Construct stiffness and directional motion through the fracture were investigated to assess the validity of construct stiffness as a surrogate measure of 3-D motion at the fracture site. Callus formation was assessed radiographically for all patients at six, twelve, and twenty-four weeks postoperatively. Univariate and multivariate linear regression analyses examined the effects of longitudinal motion, shear (transverse motion), open fracture, smoking, and diabetes on callus formation. Construct types were compared to determine whether their 3-D motion profile was associated with callus formation. RESULTS Shear disproportionately increased relative to longitudinal motion with increasing bridge span, which was not predicted by our assessment of construct stiffness alone. Callus formation was not associated with open fracture, smoking, or diabetes at six, twelve, or twenty-four weeks. However, callus formation was associated with 3-D fracture-site motion at twelve and twenty-four weeks. Longitudinal motion promoted callus formation at twelve and twenty-four weeks (p = 0.017 for both). Shear inhibited callus formation at twelve and twenty-four weeks (p = 0.017 and p = 0.022, respectively). Titanium constructs with a short bridge span demonstrated greater longitudinal motion with less shear than did the other constructs, and this was associated with greater callus formation (p < 0.001). CONCLUSIONS In this study of supracondylar femoral fractures treated with locking-plate fixation, longitudinal motion promoted callus formation, while shear inhibited callus formation. Construct stiffness was found to be a poor surrogate of fracture-site motion. Future implant design and operative fixation strategies should seek to optimize 3-D fracture-site motion rather than rely on surrogate measures such as axial stiffness.
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Affiliation(s)
- Jacob Elkins
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - J. Lawrence Marsh
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Trevor Lujan
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, Idaho
| | - Richard Peindl
- Department of Orthopaedic Surgery, Carolinas Medical Center, Charlotte, North Carolina
| | - James Kellam
- Department of Orthopaedic Surgery, University of Texas Health Science Center, Houston, Texas
| | - Donald D. Anderson
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - William Lack
- Department of Orthopaedic Surgery and Rehabilitation, Loyola University Medical Center, Maywood, Illinois
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