Bone healing in an aged murine fracture model is characterized by sustained callus inflammation and decreased cell proliferation

Geriatric fractures take longer to heal and heal with more complications than those of younger patients; however, the mechanistic basis for this difference in healing is not well understood. To improve this understanding, we investigated cell and molecular differences in fracture healing between 5‐month‐old (young adult) and 25‐month‐old (geriatric) mice healing utilizing high‐throughput analysis of gene expression. Mice underwent bilateral tibial fractures and fracture calluses were harvested at 5, 10, and 20 days post‐fracture (DPF) for analysis. Global gene expression analysis was performed using Affymetrix MoGene 1.0 ST microarrays. After normalization, data were compared using ANOVA and evaluated using Principal Component Analysis (PCA), CTen, heatmap, and Incromaps analysis. PCA and cross‐sectional heatmap analysis demonstrated that DPF followed by age had pronounced effects on changes in gene expression. Both un‐fractured and 20 DPF aged mice showed increased expression of immune‐associated genes (CXCL8, CCL8, and CCL5) and at 10 DPF, aged mice showed increased expression of matrix‐associated genes, (Matn1, Ucma, Scube1, Col9a1, and Col9a3). Cten analysis suggested an enrichment of CD8+ cells and macrophages in old mice relative to young adult mice and, conversely, a greater prevalence of mast cells in young adult mice relative to old. Finally, consistent with the PCA data, the classic bone healing pathways of BMP, Indian Hedgehog, Notch and Wnt clustered according to the time post‐fracture first and age second. Clinical Significance: Greater understanding of age‐dependent molecular changes with healing will help form a mechanistic basis for therapies to improve patient outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:149–158, 2018.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142531/1/jor23652.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142531/2/jor23652_am.pd

Needle Arthroscopy as a Reduction Aid for Lower Extremity Peri-Articular Fractures: Case Series and Technical Tricks

Background: Intra-articular fractures represent a challenging group of injuries that can occur in many different locations. In addition to restoring the mechanical alignment and stability of the extremity, accurate reduction of the articular surface is a primary goal for the treatment of peri-articular fractures. A variety of methods have been deployed to assist in the visualization and subsequent reduction of the articular surface, each with a unique set of pros and cons. The ability to visualize the articular reduction must be balanced against the soft tissue trauma required for extensile exposures. Arthroscopic assisted reduction has gained popularity for the treatment of a variety of articular injuries. Recently, needle based arthroscopy has been developed, predominantly as an outpatient tool for the diagnosis of intra-articular pathology. We present an initial experience with and technical tricks for the use of a needle based arthroscopic camera in the treatment of lower extremity peri-articular fractures. Methods: A retrospective review of all cases where needle arthroscopy was used as a reduction adjunct in lower extremity peri-articular fractures at a single, academic, level one trauma center was performed. Results: Five patients with six injuries were treated with open reduction internal fixation with adjunctive needle based arthroscopy. Early experience and tips and tricks for successful utilization of this technique are presented. Conclusion: Needle based arthroscopy may represent a valuable adjunct in the treatment of peri-articular fractures and warrants further investigation