A Novel Patient Selection Tool Is Highly Efficacious at Identifying Candidates for Outpatient Surgery When Applied to a Nonselected Cohort of Patients in a Community Hospital.

BACKGROUND: There is a paucity of validated selection tools to assess which patients can safely and predictably undergo same-day or 23-hour discharge in a community hospital. The purpose of this study was to assess the ability of our patient selection too to identify patients who are candidates for outpatient total joint arthroplasty (TJA) in a community hospital. METHODS: A retrospective review of 223 consecutive (unselected) primary TJAs was performed. The patient selection tool was retrospectively applied to this cohort to determine eligibility for outpatient arthroplasty. Utilizing length of stay and discharge disposition, we identified the proportion of patients discharged home within 23 hours. RESULTS: We found that 179 (80.1%) patients met eligibility criteria for short-stay TJA. Of the 223 patients in this study, 215 (96.4%) patients were discharged home; 17 (7.9%) were on the day of surgery, and 190 (88.3%) within 23 hours. Of the 179 eligible patients for short-stay discharge, 155 (86.6%) patients were discharged home within 23 hours. Overall, the sensitivity of the patient selection tool was 79%, the specificity was 92%, the positive predictive value was 87% and the negative predictive value was 96%. CONCLUSION: In this study, we found that more than 80% of patients undergoing TJA in a community hospital are eligible for short-stay arthroplasty with this selection tool. We found that this selection tool is safe and effective at predicting short-stay discharge. Further studies are needed to better ascertain the direct effects of these specific demographic traits on their effects on short-stay protocols.

One and a Half-Stage Revision With Prosthetic Articulating Spacer for Definitive Management of Knee Periprosthetic Joint Infection.

This paper is a comprehensive review that describes indications, contraindications, clinical outcomes, and pearls and pitfalls of 1.5-stage revision total knee arthroplasty (TKA) utilizing a primary TKA femoral component, all-polyethylene tibial component, and hand-crafted antibiotic cement for the management of chronic periprosthetic joint infection. The 1.5-stage exchange TKA details placement of an articulating spacer for an indefinite period, prolonging revision until reinfection, deterioration of functional status, or construct failure. A 1.5-stage revision TKA technique is a viable option for treatment of chronic periprosthetic knee infections. The inherent advantages of decreased health-care costs, decreased morbidity and mortality, and improved emotional ease from having a single procedure is attractive, especially if reinfection rates are determined to be equivocal to 2-stage revision.

Laboratory-Reported Normal Value Ranges Should Not Be Used to Diagnose Periprosthetic Joint Infection.

INTRODUCTION: Clinical laboratories offer several multipurpose tests, such as the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), which are not intended to diagnose any specific disease but are used by clinicians in multiple fields. The results and laboratory interpretation (normal/abnormal) of these multipurpose tests are based on laboratory-reported normal thresholds, which vary across clinical laboratories. In 2018, the International Consensus Meeting on Musculoskeletal Infection (2018 ICM) provided a gold-standard definition to diagnose periprosthetic joint infection (PJI) which included many multipurpose laboratory tests, along with thresholds optimized to diagnose PJI. The discrepancy between laboratory-reported normal thresholds and 2018 ICM-recommended PJI-optimized test thresholds has never been studied. The purpose of this study was to assess the existing variation in laboratory-reported normal thresholds for tests commonly used to diagnose PJI and evaluate the potential diagnostic impact of using laboratory-reported normal thresholds instead of 2018 ICM-recommended PJI-optimized thresholds. METHODS: Clinical laboratories (N=85) were surveyed to determine the laboratory-reported units of measure and normal thresholds for common multipurpose tests to diagnose PJI, including the ESR, CRP, D-dimer, synovial fluid white blood cells (SF-WBC), and polymorphonuclear cell percent (SF-PMN%). The variability of units of measure and normal thresholds for each test was then assessed among the 85 included clinical laboratories. A representative dataset from patients awaiting a revision arthroplasty was used to determine the clinical significance of the existing discrepancy between laboratory-reported normal test interpretations and 2018 ICM-recommended PJI-optimized test interpretations. RESULTS: Two units of measure for the CRP and six units of measure for the D-dimer were observed, with only 59% of laboratories reporting the CRP in terms of mg/L and only 16% reporting the D-dimer in ng/ml, as needed to utilize the 2018 ICM definition of PJI. Across clinical laboratories surveyed, the mean laboratory-reported normal thresholds for the ESR (20 mm/h), CRP (7.69 mg/L), D-dimer (500 ng/mL), SF-WBC (5 cells/uL), and SF-PMN% (25%) were substantially lower than the 2018 ICM-recommended PJI-optimized thresholds of 30 mm/h, 10 mg/L, 860 ng/mL, 3,000 cells/uL, and 70%, respectively. Interpretation of test results from a representative PJI dataset using each laboratory's normal test thresholds yielded mean false-positive rates of 14% (ESR), 18% (CRP), 42% (D-dimer), 93% (SF-WBC), and 36% (SF-PMN%) versus the ICM-recommended PJI-optimized thresholds. CONCLUSION: When reporting the results for multipurpose laboratory tests, such as the ESR, CRP, D-dimer, SF-WBC, and SF-PMN%, clinical laboratories utilize laboratory-reported units of measure and normal thresholds that are not intended to diagnose PJI, and therefore may not match the 2018 ICM recommendations. Our findings reveal that laboratory-reported normal thresholds for these multipurpose tests are well below the 2018 ICM recommendations to diagnose PJI. Clinical reliance on laboratory-reported results and interpretations, instead of strict use of the 2018 ICM-recommended units and PJI-optimized thresholds, may lead to false-positive interpretation of multipurpose laboratory tests.

Periprosthetic Fractures Through Tracking Pin Sites Following Computer Navigated and Robotic Total and Unicompartmental Knee Arthroplasty: A Systematic Review.

BACKGROUND: Use of computer-assisted navigation (CAN) and robotic-assisted (RA) surgery in total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) both necessitate the use of tracking pins rigidly fixed to the femur and tibia. Although periprosthetic fractures through tracking pin sites are rare, there is a paucity of literature on this potential complication. Therefore, the purpose of this study was to perform a systematic review of the current literature to assess the incidence and clinical outcomes of periprosthetic fractures through tracking pin sites following CAN and RA TKA and UKA. METHODS: A systematic review was performed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines using the PubMed, MEDLINE, and Cochrane databases in April 2020. Studies were assessed for the presence of pin site fractures, fracture characteristics, and clinical outcomes. RESULTS: Seventeen clinical studies (5 case series, 1 cohort study, and 11 case reports) involving 29 pin-related fractures were included for review. The overall incidence ranged from 0.06% to 4.8%. The mean time from index arthroplasty to fracture was 9.5 weeks (range, 0 to 40 weeks). The majority of fractures occurred in the femoral diaphysis (59%). Nineteen fractures (66%) were displaced and 10 (34%) were nondisplaced or occult. The majority of cases were atraumatic in nature or involved minor trauma and were typically preceded by persistent leg pain. A transcortical pin trajectory, large pin diameter (>4 mm), diaphyseal fixation, multiple placement attempts, and the use of non-self-drilling, non-self-tapping pins were the most commonly reported risk factors for pin-related periprosthetic fractures following CAN or RA TKA. CONCLUSIONS: Surgeons should maintain a high index of suspicion for pin-related fractures in patients with ongoing leg or thigh pain after CAN or RA TKA in order to avoid fracture displacement and additional morbidity. As CAN and RA TKA have unique complication risks, the debate regarding the value of technology-assisted TKA and its cost-effectiveness continues. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Vacuum Phenomenon in the Elbow: A Case Report.

CASE: A 33-year-old man presented with a closed distal humerus fracture after a fall from scaffolding. Computed tomography demonstrated intra-articular gas, despite the lack of arthrotomy, open fracture, or skin defects. The "vacuum phenomenon" (VP), or the presence of intra-articular gas in closed injuries, has primarily been described in the axial skeleton. To our knowledge, there are no reports in fractures of the elbow. CONCLUSION: The incidence of the VP is under-reported and represents a lack of physician awareness. The VP should remain a diagnosis of exclusion; however, physicians should be aware of this phenomenon to prevent unnecessary patient harm.

Obesity and its effect on outcomes in same-day bilateral total knee arthroplasty.

BACKGROUND: The niche surgery of same-day bilateral total knee arthroplasty (sd-BTKA) continues to create debate amongst specialists in arthroplasty. To date, there is a significant lack of literature on obese patients undergoing sd-BTKA, and no study has evaluated outcomes of this procedure when compared to non-obese patients. Therefore, this study will perform a retrospective analysis to compare (I) incidence, (II) demographics, and (III) complications of sd-BTKA in non-obese, obese, and morbidly obese patients in the United States from 2009 to 2016. METHODS: The National Inpatient Sample (NIS) database was queried for all individuals that underwent sd-BTKA from 2009 to 2016. This returned 184,844 non-obese patients, 39,901 obese patients, and 20,394 morbidly obese patients. Analyzed variables included mean age, mean length of stay (LOS), race, payer, age-adjusted Charlson Comorbidity Index score, discharge disposition, hospital charges, hospital costs, and complications. Chi-square analyses and analyses of variance were utilized to assess categorical and continuous variables, respectively. RESULTS: Non-obese patients most commonly underwent sd-BTKA over the course of the study. As weight status increased, mean age decreased and the proportion of females, LOS, hospital charges and costs, and proportion of discharges to skilled nursing facilities increased. Regression analysis demonstrated obese and morbidly obese cohorts were at an overall increased odds for experiencing complications. Specifically, obese patients were at increased risk for pulmonary emboli, periprosthetic joint infections, and respiratory failures, while morbidly obese patients are at increased risk for pulmonary emboli, respiratory failures, and urinary tract infections. CONCLUSIONS: Surgeons should thoroughly evaluate the risks and benefits of performing sd-BTKA on obese and morbidly obese patients, as both confer higher overall complication rates and increased length of stay. More research is necessary to characterize the cost analysis of this procedure, as health care models continue to transition to more cost-effective procedures.

Perioperative Antibiotic Prophylaxis in Total Joint Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: The 2017 U.S. Centers for Disease Control and Prevention (CDC) guidelines for the prevention of surgical site infection (SSI) recommended against continuation of antibiotics postoperatively after total joint arthroplasty. This is disconcerting, as the revised guidelines are based on only 6 orthopaedic studies, of which 83% (5 of 6) were published from 1987 to 1991. The purpose of the current study was to conduct a systematic review and meta-analysis of the literature regarding the efficacy and duration of surgical antibiotic prophylaxis (SAP) in total joint arthroplasty. METHODS: PubMed, Ovid MEDLINE, and Ovid Embase were screened for "surgical antimicrobial prophylaxis orthopedic," in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, without a specified time frame with respect to publication date. A total of 693 studies were screened, and 32 studies were evaluated. Data were extracted regarding antibiotic type, number of doses, and duration. Prospective and retrospective studies examining perioperative antibiotics with subsequent SSI and periprosthetic joint infection (PJI) rates in total joint arthroplasty were included. RESULTS: Twenty-three randomized controlled trials (RCTs) and 2 prospective cohort, 3 retrospective cohort, and 4 case-control studies with a total of 51,627 patients were included in this review. The overall pooled effect for the comparison between a single preoperative dose of antibiotic and continued (preoperative plus postoperative) administration was 0.96 (95% confidence interval [CI], 0.73 to 1.26), suggesting no difference in effect. However, the 95% CI for the relative risk would include a reduction of approximately 27% in either group. The overall pooled effect from the comparison between SAP of ≤24 and >24 hours postoperatively demonstrated no difference in effect. All included studies were underpowered and heterogenous regarding type of antibiotic used and duration. CONCLUSIONS: Our review confirms the benefit of SAP utilization in total joint arthroplasty. The available evidence does not show added benefit of postoperative SAP or continuation beyond 24 hours. However, the overall GRADE (Grading of Recommendations Assessment, Development and Evaluation) of evidence of the available literature was low (high risk of bias, high risk of publication bias, and low precision). The findings of this study demonstrate the need for Level-I studies with adequate power to evaluate the safety of shortened SAP duration after total joint arthroplasty and its effect on SSI/PJI prior to widespread implementation. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Bilateral Femoral Neck Fractures in a Middle-Aged Female After a Low-Energy Fall.

BACKGROUND: Bilateral hip fractures after low-energy mechanism are a rare phenomenon. Most published case reports include presentations of bilateral hip fractures in the elderly with low-energy mechanism. There is no report, to our knowledge, that illustrates this rare occurrence in middle-aged individuals after a low-energy fall from standing height. CASE PRESENTATION: We present a case of a 50-year-old female with history of cerebrovascular accident (CVA) who presented to our institution with bilateral valgus-impacted femoral neck fractures after a mechanical fall from standing height. The patient underwent successful in-situ percutaneous screw placement in bilateral hips. CONCLUSION: Although patient age is an obvious risk factor, middle-aged individuals with a medical history affecting bone mineral content may also be prone to bilateral insufficiency fractures. Individuals complaining of joint pain (with a history of conditions including renal failure, obesity, endocrinopathies, etc.) should have advanced imaging, if screening plain radiographs are negative, in an effort to identify occult fractures.

Measurement of heterogeneous reaction rates: three strategies for controlling mass transport and their application to indium-mediated allylations.

We describe three new strategies for determining heterogeneous reaction rates using photomicroscopy to measure the rate of retreat of metal surfaces: (i) spheres in a stirred solution, (ii) microscopic powder in an unstirred solution, and (iii) spheres on a rotating shaft. The strategies are applied to indium-mediated allylation (IMA), which is a powerful tool for synthetic chemists because of its stereoselectivity, broad applicability, and high yields. The rate-limiting step of IMA, reaction of allyl halides at indium metal surfaces, is shown to be fast, with a minimum value of the heterogeneous rate constant of 1 × 10(-2) cm/s, an order of magnitude faster than the previously determined minimum value. The strategies described here can be applied to any reaction in which the surface is retreating or advancing, thereby broadening the applicability of photomicroscopy to measuring heterogeneous reaction kinetics.