The Senescence Accelerated-Prone mouse variant 6 (SAMP6) shows normal growth followed by rapid aging, development of osteopenia, and shortened lifespan, compared with control R1 mice. Because oxidative stress is a fundamental mechanism of tissue aging, we tested whether cellular parameters that are associated with oxidative stress are impaired with marrow from SAMP6 mice. We compared in vitro hematopoiesis, irradiation sensitivity, proliferative potential, and osteoblastogenesis with marrow cells from SAMP6 and R1 mice. Marrow cells from SAMP6 mice showed shortened in vitro hematopoiesis; their stromal cells showed greater radiation sensitivity and decreased proliferation. Consistent with those properties, there was constitutive upregulation of TGF-β1, an inhibitor of hematopoiesis, and of cell cycle inhibitory genes, p16INK4A and p19ARF. Paradoxically, there was constitutive expression of osteoblast genes in stromal cells from SAMP6 mice, but in vitro matrix mineralization was impaired. These studies and data included in other reports indicate that impaired proliferation of osteoblast progenitors in SAMP6 marrow may be a major factor contributing to accelerated loss of bone mass. In sum, marrow from SAMP6 mice had diminished capacity for long-term hematopoiesis, increased radiosensitivity, and reduced proliferative capacity.

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Background: There has been a rapid increase in research applying artificial intelligence (AI) to various subspecialties of orthopaedic surgery, including foot and ankle surgery. The purpose of this systematic review is to (1) characterize the topics and objectives of studies using AI in foot and ankle surgery, (2) evaluate the performance of their models, and (3) evaluate their validity (internal or external validation). Methods: A systematic literature review was conducted using PubMed/MEDLINE and Embase databases in December 2022. All studies that used AI or its subsets machine learning (ML) and deep learning (DL) in the setting of foot and ankle surgery relevant to orthopaedic surgeons were included. Studies were evaluated for their demographics, subject area, outcomes of interest, model(s) tested, model(s)’ performance, and validity (internal or external). Results: A total of 31 studies met inclusion criteria: 14 studies investigated AI for image interpretation, 13 studies investigated AI for clinical predictions, and 4 studies were grouped as “other.” Studies commonly explored AI for ankle fractures, calcaneus fractures, hallux valgus, Achilles tendon pathologies, plantar fasciitis, and sports injuries. For studies reporting the area under the receiver operating characteristic curve (AUC), AUCs ranged from 0.64 (poor) to 0.99 (excellent). Two studies (6.45%) reported external validation. Conclusion: Applications of AI in the field of foot and ankle surgery are expanding, particularly for image interpretation and clinical predictions. Current model performances range from poor to excellent, and most studies lack external validation, demonstrating a need for further research prior to deploying AI-based clinical applications. Level of Evidence: Level III, retrospective cohort study.

Introduction Few studies have analyzed the effect of preoperative opioid use on postoperative outcomes after total shoulder arthroplasty (TSA). Methods Patients undergoing TSA were identified in the Pearldiver Humana Claims Dataset and stratified by level of preoperative opioid use. Primary outcomes were 90-day complications, readmissions, and revision surgery. Chi-square test and ANOVA were used to evaluate categorical and continuous variables respectively. A multivariable logistic regression analysis and a sub analysis excluding fracture as a primary diagnosis were completed. Results 18,791 patients underwent aTSA and rTSA including 9933 opioid naïve patients, 3016 sporadic opioid users and 5842 persistent opioid users. Significant differences were found in complications (6.0% vs 6.1% vs 9.1%, p < .001), readmission (7.6% vs 8.2% vs 12.6%, p < .001), and revision procedures (1.1% vs 1.1% vs 2.3%, p < .001) which remained significant after excluding fractures. After adjusting for comorbidity burden, persistent opioid use was associated with increased likelihood of complications (OR 1.4, 1.2–1.6), readmission (OR 1.6, 1.5–1.8) and revision procedures (OR 1.9, 1.5–2.4). This association remained after excluding fractures. Conclusion Persistent preoperative opioid use is associated with increased risk of early postoperative complications, readmission, and revision surgery for patients undergoing shoulder arthroplasty.