Background: Animal models are used to guide management of periprosthetic implant infections. No adequate model exists for periprosthetic shoulder infections, and clinicians thus have no preclinical tools to assess potential therapeutics. We hypothesize that it is possible to establish a mouse model of shoulder implant infection (SII) that allows noninvasive, longitudinal tracking of biofilm and host response through in vivo optical imaging. The model may then be employed to validate a targeting probe (1D9-680) with clinical translation potential for diagnosing infection and image-guided débridement. Methods: A surgical implant was press-fit into the proximal humerus of c57BL/6J mice and inoculated with 2 μL of 1 × 10 3 (e3), or 1 × 10 4 (e4), colony-forming units (CFUs) of bioluminescent Staphylococcus aureus Xen-36. The control group received 2 μL sterile saline. Bacterial activity was monitored in vivo over 42 days, directly (bioluminescence) and indirectly (targeting probe). Weekly radiographs assessed implant loosening. CFU harvests, confocal microscopy, and histology were performed. Results: Both inoculated groups established chronic infections. CFUs on postoperative day (POD) 42 were increased in the infected groups compared with the sterile group (P < .001). By POD 14, osteolysis was visualized in both infected groups. The e4 group developed catastrophic bone destruction by POD 42. The e3 group maintained a congruent shoulder joint. Targeting probes helped to visualize low-grade infections via fluorescence. Discussion: Given bone destruction in the e4 group, a longitudinal, noninvasive mouse model of SII and chronic osteolysis was produced using e3 of S aureus Xen-36, mimicking clinical presentations of chronic SII. Conclusion: The development of this model provides a foundation to study new therapeutics, interventions, and host modifications.

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Background: Surgical treatment options for proximal humeral fractures include hemiarthroplasty (HA), reverse shoulder arthroplasty (RSA), and open reduction and internal fixation (ORIF). The objectives of this study were to analyze the trends in surgical treatment of proximal humeral fractures across a decade and to compare complications, reoperation rates, and readmission rates between ORIF and RSA.Methods: The PearlDiver MUExtr Database was used to identify patients with proximal humeral fractures who were treated with ORIF, HA, or RSA between 2010 and 2019 and analyze yearly trends. Complications, revision procedures, demographic characteristics, comorbidities, and emergency room visits and hospital readmissions within 90 days of the surgical procedure were compared between ORIF and RSA cohorts for patients who had at least 2-year follow-up data.Results: In this study, 384,158 patients with proximal humeral fractures were identified in the 10-year period between 2010 and 2019. There was a significant increase in the frequency of RSA and a decrease in the frequency of ORIF and HA over time (p < 0.0001). Compared with patients who underwent ORIF or HA, patients who underwent RSA were more likely to be older (p < 0.0001), to be female, and to have a higher Charlson Comorbidity Index. Patients who underwent ORIF had higher complication rates (23.03% compared with 18.62%; p < 0.0001) and higher reoperation rates (20.3% compared with 10.3%; p < 0.0001) than patients who underwent RSA. Patients who underwent RSA had higher emergency room visit rates (20.0% compared with 16.7%; p < 0.001) and hospital readmission rates (12.9% compared with 7.3%; p < 0.0001) within 90 days of the surgical procedure compared with patients who underwent ORIF.Conclusions: There has been an increasing trend in RSA utilization for the surgical treatment of proximal humeral fractures, along with a decreasing trend in HA and ORIF, over time. Patients who underwent ORIF for a proximal humeral fracture had higher complication and reoperation rates compared with patients who underwent RSA. Patients who underwent RSA had higher emergency room visit and hospital readmission rates within 90 days of the surgical procedure compared with patients who underwent ORIF, which may be attributable to the RSA cohort being older and having more comorbidities.

Purpose To utilise a large cross-sectional database to analyse the efects of time duration between diagnosis of anterior cruciate ligament (ACL) tear and ACL reconstruction (ACLR) on concomitant procedures performed and subsequent surgery within 2 years. Methods An analysis from 2015 to 2018 was performed using the Mariner PearlDiver Patient Records Database. Current Procedural Terminology (CPT), and International Classiication of Diseases (ICD-10) codes identiied patients with a diagnosis of ACL tear who underwent subsequent ACLR. Patients were stratiied in biweekly and bimonthly increments based on the time duration between initial diagnosis of ACL tear and surgical treatment. Chi-squared analysis was used to compare categorical variables, and trend analysis was performed with Cochran-Armitage independence testing. Results Of 11,867 patients who underwent ACLR, 76.1% underwent surgery within 2 months of injury diagnosis. Patients aged 10-19 were most likely to undergo surgery within 2 months of injury diagnosis (83.5%, P < 0.0001). As duration from injury diagnosis to ACLR increased from < 2 months to > 6 months, rates of concomitant meniscectomy increased from 9.1% to 20.5% (P < 0.0001). The overall 2-year subsequent surgery rate was 5.3%. The incidence of revision ACLR was highest for patients who underwent surgery > 6 months after diagnosis (P < 0.0001), whilst the incidence of ipsilateral lysis of adhesions and manipulation under anaesthesia (MUA) was highest for patients who underwent surgery < 2 months after diagnosis (P < 0.0001). ACLR at 6-8 weeks after diagnosis demonstrated the lowest risk for concomitant procedures as well as 2-year subsequent surgery. ConclusionThe majority of patients undergo ACL reconstruction within 2 months of initial ACL tear diagnosis. Delayed surgery greater than 6 months after the diagnosis of an ACL rupture leads to increased need for concomitant meniscectomy as well as higher risk for revision ACLR within 2 years, but immediate surgery may increase risk for knee arthroibrosis.

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