Nutritional Laboratory Studies Prior to Total Knee Arthroplasty: Practice Versus Publication.

BACKGROUND: Recent emphasis has been placed on nutritional status assessment prior to total knee arthroplasty (TKA), including multiple American Academy of Orthopaedic Surgeons publications recommending specific laboratory studies; however, the frequency with which surgeons obtain these laboratory studies remains unclear. We sought to assess the incidence of ordering nutritional laboratory studies in the 90 days prior to TKA, utilizing data from a large administrative claims database. METHODS: With use of the PearlDiver database, we identified 557,670 patients undergoing primary TKA from 2011 to 2020 with a metabolic panel or blood cell count claim within 90 days prior to TKA. We then determined the incidence of prealbumin, transferrin, vitamin D, and zinc laboratory tests claimed 90 days prior to TKA. Associations between claims and the year of surgery, patient demographics, and clinical characteristics were assessed by comparing proportions and chi-square testing. RESULTS: Nutritional laboratory studies were infrequently claimed within 90 days prior to TKA, with studies for prealbumin being performed in 2.2% of patients; transferrin, 1.9%; vitamin D, 10.2%; and zinc, 0.2%. From 2011 to 2020, there was a moderate but steady increase in the proportion of patients with claims for prealbumin (change from 0.8% in 2011 to 3.4% in 2020; p < 0.001), transferrin (0.8% to 2.7%; p < 0.001), and vitamin D (7.6% to 9.4%; p < 0.001) laboratory tests but there was less of a change for zinc (0.1% to 0.2%; p < 0.001). There were weak-to-absent associations of age, gender, obesity, diabetes, and anemia with laboratory claims. CONCLUSIONS: Despite multiple publications and recommendations, nutritional laboratory studies are infrequently ordered prior to TKA. Although there has been a slight increase in the use of nutritional laboratory studies over the past decade, patient factors such as gender and obesity were not associated with this increase. Understanding current practice patterns may help target future areas for improvement. LEVEL OF EVIDENCE: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions.

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510 GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510 GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02

Outcomes with Endovascular Treatment of Patients with M2 Segment MCA Occlusion in the Late Time Window.

BACKGROUND AND PURPOSE: Randomized trials in the late window have demonstrated the efficacy and safety of endovascular thrombectomy in large-vessel occlusions. Patients with M2-segment MCA occlusions were excluded from these trials. We compared outcomes with endovascular thrombectomy in patients with M2-versus-M1 occlusions presenting 6-24 hours after symptom onset. MATERIALS AND METHODS: Analyses were on pooled data from studies enrolling patients with stroke treated with endovascular thrombectomy 6-24 hours after symptom onset. We compared 90-day functional independence (mRS ≤ 2), mortality, symptomatic intracranial hemorrhage, and successful reperfusion (expanded TICI = 2b-3) between patients with M2 and M1 occlusions. The benefit of successful reperfusion was then assessed among patients with M2 occlusion. RESULTS: Of 461 patients, 367 (79.6%) had M1 occlusions and 94 (20.4%) had M2 occlusions. Patients with M2 occlusions were older and had lower median baseline NIHSS scores. Patients with M2 occlusion were more likely to achieve 90-day functional independence than those with M1 occlusion (adjusted OR = 2.13; 95% CI, 1.25-3.65). There were no significant differences in the proportion of successful reperfusion (82.9% versus 81.1%) or mortality (11.2% versus 17.2%). Symptomatic intracranial hemorrhage risk was lower in patients with M2-versus-M1 occlusions (4.3% versus 12.2%, P = .03). Successful reperfusion was independently associated with functional independence among patients with M2 occlusions (adjusted OR = 2.84; 95% CI, 1.11-7.29). CONCLUSIONS: In the late time window, patients with M2 occlusions treated with endovascular thrombectomy achieved better clinical outcomes, similar reperfusion, and lower symptomatic intracranial hemorrhage rates compared with patients with M1 occlusion. These results support the safety and benefit of endovascular thrombectomy in patients with M2 occlusions in the late window.

Prospective association between maternal allostatic load during pregnancy and child mitochondrial content and bioenergetic capacity.

BACKGROUND: Mitochondria are multifunctional energy-producing and signaling organelles that support life and contribute to stress adaptation. There is a growing understanding of the dynamic relationship between stress exposure and mitochondrial biology; however, the influence of stress on key domains of mitochondrial biology during early-life, particularly the earliest phases of intra-uterine/prenatal period remains largely unknown. Thus, the goal of this study was to examine the impact of fetal exposure to stress (modeled as the biological construct allostatic load) upon mitochondrial biology in early childhood. METHODS: In n = 30 children (range: 3.5-6 years, 53% male), we quantified mitochondrial content via citrate synthase (CS) activity and mtDNA copy number (mtDNAcn), and measured mitochondrial bioenergetic capacity via respiratory chain enzyme activities (complexes I (CI), II (CII), and IV (CIV)) in platelet-depleted peripheral blood mononuclear cells (PBMCs). In a cohort of healthy pregnant women, maternal allostatic load was operationalized as a latent variable (sum of z-scores) representing an aggregation of early-, mid- and late-gestation measures of neuroendocrine (cortisol), immune (interleukin-6, C-reactive protein), metabolic (homeostasis model assessment of insulin resistance, free fatty acids), and cardiovascular (aggregate systolic and diastolic blood pressure) systems, as well as an anthropometric indicator (pre-pregnancy body mass index [BMI]). RESULTS: An interquartile increase in maternal allostatic load during pregnancy was associated with higher mitochondrial content (24% and 15% higher CS and mtDNAcn), and a higher mitochondrial bioenergetic capacity (16%, 23%, and 25% higher CI, CII and CIV enzymatic activities) in child leukocytes. The positive association between maternal allostatic load during pregnancy and child mitochondrial content and bioenergetic capacity remained significant after accounting for the effects of key pre- and post-natal maternal and child covariates (p's < 0.05, except CI p = 0.073). CONCLUSION: We report evidence that prenatal biological stress exposure, modeled as allostatic load, was associated with elevated child mitochondrial content and bioenergetic capacity in early childhood. This higher mitochondrial content and bioenergetic capacity (per leukocyte) may reflect increased energetic demands at the immune or organism level, and thus contribute to wear-and-tear and pathophysiology, and/or programmed pro-inflammatory phenotypes. These findings provide potential mechanistic insight into the cellular processes underlying developmental programming, and support the potential role that changes in mitochondrial content and bioenergetic functional capacity may play in altering life-long susceptibility for health and disease.

Self-Reported Health of Severely Obese US Adults With Osteoarthritis.

BACKGROUND: Severe obesity is associated with complications following arthroplasty, leading surgeons to increasingly counsel patients regarding weight loss. For patients seeking arthroplasty, learning that severe obesity may be a relative contraindication to surgery can create a challenging clinical interaction. We sought to describe the self-reported health of United States (US) adults who had severe obesity and osteoarthritis (OA) to better understand patient perspectives. METHODS: The National Health and Nutrition Examination Survey, a nationally representative sample of the US population, was used to identify adult participants who had a body mass index (BMI) over 35 and an OA diagnosis. In total, 889 participants representing a US population of 9,604,722 were included. Self-reported health was dichotomized as poor to fair versus good to excellent. Analyses were weighted to produce national estimates. Associations between obesity severity and patient characteristics with self-reported health were assessed. RESULTS: Of US adults with a BMI over 35 and OA diagnosis, 64% rated their health as good or better. For adults who had a BMI over 45, 55% still reported their health as good or better. The strongest predictors of self-reported health were measures of physical functioning. Only 37% of participants who had much difficulty walking a quarter mile rated their health as good or better compared to 86% without difficulty (P < .001). CONCLUSION: Approximately two-thirds of patients who have severe obesity and OA do not perceive their health as compromised and consider decreased physical function as the primary driver of decreased health. This suggests that counseling about the association between obesity and overall health may improve shared decision making and that patient satisfaction metrics may be difficult to interpret in these clinical situations.

Functional outcomes of early laryngeal cancer - endoscopic laser surgery versus external beam radiotherapy: a systematic review.

OBJECTIVE: Current evidence suggests there is no difference between endoscopic laser surgery and radiotherapy with regards to oncological outcomes of early laryngeal cancer. Patient management may therefore be directed towards voice and quality of life outcomes. This systematic review compares functional outcomes with respect to voice character, swallowing outcomes and quality of life for endoscopic laser surgery versus radiotherapy for T1 and T2 stage laryngeal carcinoma. METHOD: Search terminology was designed by both authors and used in Cochrane, PubMed and Web of Science databases. Studies of adult patients treated for primary T1 and T2 laryngeal squamous cell carcinoma utilising one objective (validated) measure of quality of life, swallowing or voice were included. RESULTS: Initial searches identified 1767 studies. After inclusion and exclusion criteria were applied, 42 studies were identified for full-text review. CONCLUSION: This review concluded that neither treatment is clearly advantageous. Future research should be composed of further prospective studies that use a standardised assessment regime to allow valid comparison.

Preoperative assessment and optimisation for pelvic exenteration in locally advanced and recurrent rectal cancer: A review.

The pre-operative phase in planning a pelvic exenteration or extended resections is critical to optimising patient outcomes. This review summarises the key components of preoperative assessment and planning in patients with locally advanced rectal cancer (LARC) and locally recurrent rectal cancer (LLRC) being considered for potential curative resection. The preoperative period can be considered in 5 key phases: 1) Multidisciplinary meeting (MDT) review and recommendation for neoadjuvant therapy and surgery, 2) Anaesthetic preoperative assessment of fitness for surgery and quantification of risk, 3) Shared decision making with the patient and the process of informed consent, 4) Prehabilitation and physiological optimisation 5) Technical aspects of surgical planning. This review will focus on patients who have been recommended for surgery by the MDT and have completed neoadjuvant therapy. Other important considerations beyond the scope of this review are the various neoadjuvant strategies employed which in this patient group include Total Neo-adjuvant Therapy and reirradiation. Critical to improving perioperative outcomes is the dual aim of achieving a negative resection margin in a patient fit enough for extended surgery. Advanced, realistic communication is required pre-operatively and should be maintained throughout recovery. Optimising patient's physiological and psychological reserve with a preoperative prehabilitation programme is important, with physiotherapy, psychological and nutritional input. From a surgical perspective, image based technical preoperative planning is important to identify risk points and ensure correct surgical strategy. Careful attention to the entire patient journey through these 5 preoperative phases can optimise outcomes with the accumulation of marginal gains at multiple timepoints.

Periprosthetic joint infection after primary TKA in the medicare population: How frequently are patients revised at a different hospital?

BACKGROUND: Periprosthetic infection (PJI) after total knee arthroplasty (TKA) places a significant burden on hospitals. We sought to describe the proportion of patients undergoing revision for PJI at a different hospital within one year of primary TKA and whether patient characteristics or hospital volume were associated with this change. METHODS: Medicare data from 2005 to 2014 was retrospectively reviewed using PearlDiver. All patients over 64 years undergoing revision for PJI within one year of primary TKA were stratified by the revision occurring within 90 days. Hospitals were grouped by annual TKA volume as Low (<50), Medium (51-100), High (101-200), and Very High (>200). Associations of patient characteristics and hospital volume with revision at a different hospital were assessed using Chi-squared tests and Somers' D. RESULTS: Of 8,337 patients undergoing revision within 90 days of TKA, 1,370 (16%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (24% for low, 15% medium, 12% high, and 12% very high; P < 0.001). Of 7,608 patients undergoing revision between 91 and 365 days, 1,110 (15%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (26% for low, 14% medium, 10% high, and 9% very high; P < 0.001). Changing hospitals was not associated with sex or age. CONCLUSION: Patients frequently undergo revision for PJI at a different hospital, even within 90 days of TKA. Further research is needed to understand these implications of this care pathway shift.

The James A. Rand Young Investigator's Award: Are Intraoperative Cultures Necessary If the Aspiration Culture Is Positive? A Concordance Study in Periprosthetic Joint Infection.

BACKGROUND: The concordance between preoperative synovial fluid culture and multiple intraoperative tissue cultures for identifying pathogenic microorganisms in periprosthetic joint infection (PJI) remains unknown. Our aim is to determine the diagnostic performance of synovial fluid culture for early organism identification. METHODS: A total of 363 patients who met Musculoskeletal Infection Society criteria for PJI following primary total joint arthroplasty were identified from a retrospective joint infection database. Inclusion criteria required a positive preoperative intra-articular synovial fluid sample within 90 days of intraoperative tissue culture(s) at revision surgery. Concordance was defined as matching organism(s) in aspirate and intraoperative specimens. RESULTS: Concordance was identified in 279 (76.8%) patients with similar rates among total hip arthroplasties (77.2%) and total knee arthroplasties (76.4%, P = .86). Culture discordance occurred in 84 (23.1%) patients; 37 (10.2%) had no intraoperative culture growth and 33 (90.1%) were polymicrobial. Monomicrobial Staphylococcal PJI cases had high sensitivity (0.96, 95% confidence interval [CI] 0.92-0.98) and specificity (0.85, 95% CI 0.80-0.90). Polymicrobial infections had the lowest sensitivity (0.06, 95% CI 0.01-0.19). CONCLUSION: Aspiration culture has favorable sensitivity and specificity when compared to tissue culture for identifying the majority of PJI organisms. Clinicians can guide surgical treatment and postoperative antibiotics based on monomicrobial aspiration results, but they should strongly consider collecting multiple tissue cultures to maximize the chance of identifying an underlying polymicrobial PJI. LEVEL OF EVIDENCE: Level III.

Mechanisms of Light-Induced Deformations in Photoreceptors.

Biological cells deform on a nanometer scale when their transmembrane voltage changes, an effect that has been visualized during the action potential using quantitative phase imaging. Similar changes in the optical path length have been observed in photoreceptor outer segments after a flash stimulus via phase-resolved optical coherence tomography. These optoretinograms reveal a fast, millisecond-scale contraction of the outer segments by tens of nanometers, followed by a slow (hundreds of milliseconds) elongation reaching hundreds of nanometers. Ultrafast measurements of the contractile response using line-field phase-resolved optical coherence tomography show a logarithmic increase in amplitude and a decreasing time to peak with increasing stimulus intensity. We present a model that relates the early receptor potential to these deformations based on the voltage-dependent membrane tension-the mechanism observed earlier in neurons and other electrogenic cells. The early receptor potential is caused by conformational changes in opsins after photoisomerization, resulting in the fractional shift of the charge across the disk membrane. Lateral repulsion of the ions on both sides of the membrane affects its surface tension and leads to its lateral expansion. Because the volume of the disks does not change on a millisecond timescale, their lateral expansion leads to an axial contraction of the outer segment. With increasing stimulus intensity and the resulting tension, the area expansion coefficient of the disk membrane also increases as thermally induced fluctuations are pulled flat, resisting further expansion. This leads to the logarithmic saturation observed in measurements as well as the peak shift in time. This imaging technique therefore relates the structural changes in the photoreceptor to the underlying neurological function of transducing light into electrical signals. Such label-free optical monitoring of neural activity using fast interferometry may be applicable not only to optoretinography but also to neuroscience in general.

Erratum: Evolution of π

This corrects the article DOI: 10.1103/PhysRevLett.109.152301.

Clinical Experience with COVID-19 at a Specialty Orthopedic Hospital Converted to a Pandemic Overflow Field Hospital.

BACKGROUND: COVID-19, the illness caused by the novel coronavirus, SARS-CoV-2, has sickened millions and killed hundreds of thousands as of June 2020. New York City was affected gravely. Our hospital, a specialty orthopedic hospital unaccustomed to large volumes of patients with life-threatening respiratory infections, underwent rapid adaptation to care for COVID-19 patients in response to emergency surge conditions at neighboring hospitals. PURPOSES: We sought to determine the attributes, pharmacologic and other treatments, and clinical course in the cohort of patients with COVID-19 who were admitted to our hospital at the height of the pandemic in April 2020 in New York City. METHODS: We conducted a retrospective observational cohort study of all patients admitted between April 1 and April 21, 2020, who had a diagnosis of COVID-19. Data were gathered from the electronic health record and by manual chart abstraction. RESULTS: Of the 148 patients admitted with COVID-19 (mean age, 62 years), ten patients died. There were no deaths among non-critically ill patients transferred from other hospitals, while 26% of those with critical illness died. A subset of COVID-19 patients was admitted for orthopedic and medical conditions other than COVID-19, and some of these patients required intensive care and ventilatory support. CONCLUSION: Professional and organizational flexibility during pandemic conditions allowed a specialty orthopedic hospital to provide excellent care in a global public health emergency.

Effect of Blue Light and Photosensitizers on Cutibacterium acnes on Shoulder Periprosthetic Joint Infection Isolates.

Introduction: Cutibacterium acnes is gaining recognition as a leading pathogen after orthopaedic shoulder procedures. Photodynamic therapy, a combination of light and a photosensitizer, has demonstrated antimicrobial activity against C. acnes in the treatment of acne vulgaris. We sought to evaluate the effect of photodynamic therapy using blue light and photosensitizers on C. acnes isolates from shoulder prosthetic joint infections. Methods: C. acnes strains isolated from 19 patients with shoulder PJI were exposed to blue light alone (415 nm) or in combination with photosensitizers (fluorescein, riboflavin and demeclocycline). C. acnes strains were divided into 4 categories: Highly Sensitive (HS), Sensitive (S), Weakly Sensitive (WS), Resistant to blue light. Results: 13 of 19 C. acnes strains (68%) were S or HS to blue light alone. Of these 19 strains tested, 11 were tested with blue light and fluorescein or blue light plus riboflavin. Fluorescein (1 µg/mL) enhanced the effect of blue light in 6 of 11 strains (55%). Blue light plus riboflavin (10 µg/mL) resulted enhanced killing in 3 of 11 strains (27%), but produced a paradoxical photoprotective effect in 4 of 11 strains (36%), resulting in a net decrease compared to blue light alone. Demeclocycline, however, enhanced the effect of blue light in 16 of 17 strains (94 %). Conclusions: Blue light with the addition of photosensitizers killed C. acnes from periprosthetic shoulder infections in vitro, with demeclocycline having the most pronounced effect.

Pathogenic genetic variations of C. acnes are associated with clinically relevant orthopedic shoulder infections.

Many surgeons continue to face the clinical dilemma of interpreting a positive aspiration or unexpected positive Cutibacterium acnes (C. acnes) culture. There are factors that complicate the interpretation of positive cultures including variations in both frequency of false positive cultures and virulence properties. As indices of virulence, hemolytic strains, from previously confirmed clinically infected shoulders, were compared with non-hemolytic isolates determined to be contaminants, by RNA-sequencing (RNA-Seq). Six C. acnes isolates from patients who underwent revision total shoulder arthroplasty (TSA) were identified based on previously described infection criteria. Three C. acnes isolates from each group underwent RNA-Seq. Differential gene expression analysis, principal component analysis (PCA), and heatmap analysis were used to determine the gene variation and patterning between the definite infection and probable contaminant isolates. Differential gene expression analysis identified genes that were differentially expressed between the isolates classified as definite infection and isolates classified as probable contaminants. PCA using a 500 gene subset of identified genes was able to find combinations of these genes that separated out the definite infection and probable contaminants isolates. The heatmap demonstrated similar gene expression in the three Definite Infections isolates, and significantly different expression when compared with the probable contaminant isolates. Clinical significance: C. acnes revision TSA isolates classified as definite infection and probable contaminant demonstrated a similar gene expression pattern to each respective group and different gene expression pattern when compared between groups. These findings indicate distinct differences in C. acnes strains associated with clinically relevant orthopedic TSA infections.

Utilization of Debridement, Antibiotics, and Implant Retention for Infection After Total Joint Arthroplasty Over a Decade in the United States.

BACKGROUND: Reported clinical outcomes have varied for debridement, antibiotics, and implant retention (DAIR) and little is known regarding trends in utilization. We sought to evaluate the rate of DAIR utilization for total knee arthroplasty (TKA) and total hip arthroplasty (THA) periprosthetic joint infection (PJI) over a decade and clinical factors associated with these trends. METHODS: A retrospective study of primary TKAs and THAs was performed using Medicare data from 2005 to 2014 using the PearlDiver database platform. Current Procedural Technology and International Classification of Diseases Ninth Edition codes identified patients who underwent a surgical revision for PJI, whether revision was a DAIR, as well as associated clinical factors including timing from index arthroplasty. RESULTS: The proportion of revision TKAs and THAs performed using DAIR was 27% and 12% across all years, respectively. This proportion varied by year for TKAs and THAs with a linear trend toward increasing relative use of DAIR estimated at 1.4% and 0.9% per year (P < .001; P < .001). DAIR for TKA and THA performed within 90 days increased at a faster rate, 3.4% and 2.1% per year (P < .001; P < .001). Trends over time in TKA DAIRs showed an association with Elixhauser Comorbidity Index (ECI), 0-5 group increasing at 2.0% per year (P = .03) and patients >85 years (P = .04). CONCLUSION: The proportion of revision arthroplasty cases for PJI managed with DAIR has been increasing over time in the United States, with the most substantial increase seen <90 days from index arthroplasty. Age, gender, and ECI had a minimal association with this trend, except in the TKA population >85 years and in those with a very low ECI score.

Flexion Space Balancing Through Component Positioning and Its Relationship to Traditional Anatomic Rotational Landmarks in Robotic Total Knee Arthroplasty.

BACKGROUND: The use of the femoral component position to balance the flexion space and its relationship to the transepicondylar axis (TEA) and posterior condylar angle (PCA) has not been thoroughly evaluated. METHODS: A total of 233 patients undergoing robotic arm-assisted total knee arthroplasty were evaluated. Native TEA and PCA were established on preoperative computed tomography scans. Femoral component rotation was set in the axial plane to match the native trochlea and native medial femoral condyle to set the flexion gap. Knee flexion space gaps and component position were recorded. The relationship of the femoral component to the native TEA, PCA, and preoperative radiographic landmarks was evaluated. RESULTS: The intraoperative measured medial flexion space gap did not significantly correlate with the relationship of the femoral component to the PCA or TEA in varus or valgus knees. In varus knees, the preoperative mechanical axis alignment had a positive relationship to femoral component position when compared to the PCA (P = .04) and TEA (P = .002). In valgus knees, there was a positive correlation between the preoperative lateral distal femoral angle and component position when compared to the PCA (P = .04) only. CONCLUSION: Intraoperative measured flexion space balance through femoral component positioning did not correlate with its relationship to the native TEA or PCA. In varus knees, the preoperative mechanical axis alignment correlated with an increase in femoral component external rotation to the TEA and PCA. In valgus knees, the severity of preoperative lateral distal femoral angle correlated with the rotational relationship of the femoral component to the PCA only.

Vancomycin-laden calcium phosphate-calcium sulfate composite allows bone formation in a rat infection model.

OBJECTIVE: Local antibiotic delivery systems with differing chemical and mechanical properties have been developed to assist in the management of osteomyelitis. We investigated the bone conductive and resorptive capabilities of a calcium phosphate-calcium sulfate (CaP/CaS) composite compared with commercially available polymethylmethacrylate (PMMA). In addition, we compared the in vivo preventative and treatment efficacies of both biomaterials in a proven osteomyelitis model. METHODS: Sixty-four, male Sprague-Dawley rats were inoculated with 10 µl of 1.5 x 108 CFU/ml of Staphylococcus aureus in a surgically drilled defect in the right proximal tibia. Infected animals were randomly allocated into prevention and treatment groups with 32 rats each. In the prevention group, the defect was filled with a plug containing either PMMA or CaP/CaS immediately after the inoculation. In the treatment group, the infected defects were irrigated, debrided, and filled with either a PMMA or CaP/CaS plug. Both CaP/CaS and PMMA were impregnated with 10% weight of vancomycin. Rats were sacrificed 6 weeks after cement insertion. Infection was detected by bacterial culture and histological analysis. Bone formation in the defect was assessed with micro-computed tomography and histology. RESULTS: No bacteria were detected in any group. Both the prevention and treatment groups using CaP/CaS had significantly more bone volume fraction, bone area, and cartilage area than the PMMA groups. CONCLUSIONS: When loaded with 10% of vancomycin, CaP/CaS and PMMA have the same efficacy for treatment and prevention of osteomyelitis. CaP/CaS enhances bone defect healing through improved bone remodeling in our osteomyelitis rat model.

Nationwide Organism Susceptibility Patterns to Common Preoperative Prophylactic Antibiotics: What Are We Covering?

BACKGROUND: Many periprosthetic joint infections (PJIs) are caused by organisms not susceptible to first-generation cephalosporins. We sought to evaluate the national susceptibility patterns of organisms to cefazolin and, or oxacillin, clindamycin, and vancomycin using antibiogram data. METHODS: Publically available regional and state antibiograms were evaluated for antibiotic susceptibility patterns to commonly infecting gram-positive organisms. The number of isolates tested in each antibiogram and percent of strains susceptible to oxacillin, clindamycin, and vancomycin were recorded. Oxacillin is used as a surrogate to cefazolin in antibiograms. A comparison of antibiotic susceptibilities was performed. RESULTS: Seven state and 38 regional antibiograms were reviewed. Oxacillin was a sensitive antibiotic in 99.2 ± 4.8% of methicillin-sensitive Staphylococcus aureus (MSSA) isolates, 0 ± 0% of methicillin-resistant Staphylococcus aureus (MRSA) isolates, 44.5 ± 13.7% of coagulase-negative staphylococcus organism isolates (CNS), and 30.6 ± 10.5% of Staphylococcus epidermidis isolates. Clindamycin was a sensitive antibiotic in 75.8 ± 8.4% of MSSA isolates, 60.2 ± 13.2% of MRSA isolates, 60.3 ± 11.4% of CNS isolates, and 56.2 ± 6.5% of S epidermidis isolates. Vancomycin was a sensitive antibiotic in 99.9 ± 0.4% of MSSA isolates, 99.8 ± 0.4% of MRSA isolates, 99.8 ± 0.5% of CNS isolates, and 99.6 ± 0.7% of S epidermidis isolates. Clindamycin was significantly less sensitive in MSSA isolates as compared with oxacillin and vancomycin (P < .0001). Oxacillin was significantly less sensitive in CNS, S epidermidis, and MRSA isolates as compared with clindamycin and vancomycin (P < .0001). CONCLUSION: The national clindamycin susceptibility pattern is limited to MSSA and may not have an optimal susceptibility profile suitable for use as a prophylactic antibiotic. Cefazolin continues to have excellent coverage against MSSA.