Introduction: Active learning methods have accumulated popularity due to improved results in knowledge acquisition as opposed to passive learning methods. For surgical resident physicians with limited training opportunities outside of the operating room due to time constraints, virtual reality (VR) is a relatively inexpensive and time-efficient active training method for procurement of surgical skills. We conducted a simulated intramedullary nailing (IMN) of a tibia to demonstrate VR training programs as a more effective modality of learning orthopedic surgical techniques compared to passive learning tools such as a standard guide (SG) through trained novice medical students performing a SawBones simulation of intramedullary nail fixation. Materials and methods: First and second-year medical students without prior experience of procedure were recruited and randomized to SG or VR training. Participants were observed performing simulated tibia IMN procedure immediately after training and evaluated by a blinded attending surgeon using procedure-specific checklist and 5-point global assessment scale. Participants returned after 2-weeks for repeat training and evaluation. Results: 20 participants were recruited and randomized into VR (n = 10) and SG (n = 10) groups. All 20 participants completed the first phase and 17 completed the second phase of the study. Aggregate global assessment scores were significantly higher for VR than SG group (17.5 vs. 7.5, p < 0.001), including scores in all individual categories. The percentage of steps completed correctly was significantly higher in the VR group compared to the SG group (63% vs. 25%, p < 0.002). Average improvement between the first and second phases of the study were higher in the VR group compared to SG group across all 5-categories of the global assessment scale, and significantly higher for knowledge of instruments (50% vs. 11%, p, 0.01). Discussion: VR training was more effective than a passive SG in our model of simulated tibia IMN for novice medical students. Virtual reality training may be a useful method to augment orthopedic education.

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Implant related infections are the most common cause of joint arthroplasty failure, requiring revision surgeries and a new implant, resulting in a cost of $8.6 billion annually. To address this problem, we created a class of coating technology that is applied in the operating room, in a procedure that takes less than 10 min, and can incorporate any desired antibiotic. Our coating technology uses an in situ coupling reaction of branched poly(ethylene glycol) and poly(allyl mercaptan) (PEG-PAM) polymers to generate an amphiphilic polymeric coating. We show in vivo efficacy in preventing implant infection in both post-arthroplasty infection and post-spinal surgery infection mouse models. Our technology displays efficacy with or without systemic antibiotics, the standard of care. Our coating technology is applied in a clinically relevant time frame, does not require modification of implant manufacturing process, and does not change the implant shelf life.

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Background: Although the risks of continued opioid use following inpatient total joint arthroplasty (TJA) have been well-studied, these risks in the outpatient setting are not well known. The purpose of the present study was to characterize opioid use following outpatient compared with inpatient TJA. Methods: In this retrospective cohort study, opioid-naïve patients who underwent inpatient or outpatient (no overnight stay) primary, elective TJA from 2007 to 2017 were identified within a large national commercial-claims insurance database. For inclusion in the study, patients had to have been continuously enrolled in the database for ≥12 months prior to and ≥6 months after the TJA procedure. Multivariable analyses controlling for demographics, geography, procedure, year, and comorbidities were utilized to determine the association between surgical setting and risk of persistent opioid use, defined as the patient still filling new opioid prescriptions >90 days postoperatively. Results: We identified a total of 92,506 opioid-naïve TJA patients, of whom 57,183 (61.8%) underwent total knee arthroplasty (TKA). Overall, 7,342 patients (7.9%) underwent an outpatient TJA procedure, including 4,194 outpatient TKAs. Outpatient TJA was associated with reduced surgical opioid prescribing (78.9% compared with 87.6% for inpatient procedures; p < 0.001). Among the 80,393 patients (86.9%) who received surgical opioids, the total amount of opioids prescribed (in morphine milligram equivalents) was similar between inpatient (median, 750; interquartile range, 450 to 1,200) and outpatient procedures (median, 750; interquartile range, 450 to 1,140; p = 0.47); however, inpatient TJA patients were significantly more likely to still be taking opioids after 90 days postoperatively (11.4% compared with 9.0% for outpatient procedures; p < 0.001). These results persisted in adjusted analysis (adjusted odds ratio, 1.13; 95% confidence interval, 1.03 to 1.24; p = 0.01). Conclusions: Outpatient TJA patients who received opioid prescriptions were prescribed a similar amount of opioids as those undergoing inpatient TJA procedures, but were significantly less likely to become persistent opioid users, even when controlling for patient factors. Outpatient TJA, as compared with inpatient TJA, does not appear to be a risk factor for new opioid dependence, and these findings support the continued transition to the outpatient-TJA model for lower-risk patients. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Extremity reconstruction surgery is increasingly performed rather than amputation for patients with large-segment pathologic bone loss. Debate persists as to the optimal void filler for this “limb salvage” surgery, whether metal or allograft bone. Clinicians focus on optimizing important functional gains for patients, and the risk of devastating implant infection has been thought to be similar regardless of implant material. Recent insights into infection pathophysiology are challenging this equipoise, however, with both basic science data suggesting a novel mechanism of infection of Staphylococcus aureus (the most common infecting agent) into the host lacunar–canaliculi network, and also clinical data revealing a higher rate of infection of allograft over metal. The current translational study was therefore developed to bridge the gap between these insights in a longitudinal murine model of infection of allograft bone and metal. Real-time Staphylococci infection characteristics were quantified in cortical bone vs metal, and both microarchitecture of host implant and presence of host immune response were assessed. An orders-of-magnitude higher bacterial burden was established in cortical allograft bone over both metal and cancellous bone. The establishment of immune-evading microabscesses was confirmed in both cortical allograft haversian canal and the submicron canaliculi network in an additional model of mouse femur bone infection. These study results reveal a mechanism by which Staphylococci evasion of host immunity is possible, contributing to elevated risks of infection in cortical bone. The presence of this local infection reservoir imparts massive clinical implications that may alter the current paradigm of osteomyelitis and bulk allograft infection treatment.

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.

Background:The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI.Methods:Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis.Results:The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections.Conclusions:NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial.Level of Evidence:Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.