Perioperative Cefazolin for Total Joint Arthroplasty Patients Who Have a Penicillin Allergy: Is It Safe?

BACKGROUND: Cefazolin is the standard of care for perioperative antibiotic prophylaxis in total joint arthroplasty (TJA) in the United States. The potential allergic cross-reactivity between cefazolin and penicillin causes uncertainty regarding optimal antibiotic choice in patients who have a reported penicillin allergy (rPCNA). The purpose of this study was to determine the safety of perioperative cefazolin in PCNA patients undergoing primary TJA. METHODS: We identified all patients (n = 49,842) undergoing primary total hip arthroplasty (n = 25,659) or total knee arthroplasty (n = 24,183) from 2016 to 2022 who received perioperative intravenous antibiotic prophylaxis. Patients who had an rPCNA (n = 5,508) who received cefazolin (n = 4,938, 89.7%) were compared to rPCNA patients who did not (n = 570, 10.3%), and to patients who did not have an rPCNA (n = 43,359). The primary outcome was the rate of allergic reactions within 72 hours postoperatively. Secondary outcomes included the rates of superficial infections, deep infections, and Clostridioides difficile infections within 90 days. RESULTS: The rate of allergic reactions was 0.1% (n = 5) in rPCNA patients who received cefazolin, compared to 0.2% (n = 1) in rPCNA patients who did not (P = .48) and 0.02% (n = 11) in patients who have no rPCNA (P = .02). Allergic reactions were mild in all 5 rPCNA patients who received cefazolin and were characterized by cutaneous symptoms (n = 4) or dyspnea in the absence of respiratory distress (n = 1) that resolved promptly with antibiotic discontinuation and administration of antihistamines and/or corticosteroids. We observed no differences in the rates of superficial infections (0.1 versus 0.2%, P = .58), deep infections (0.3 versus 0.4%, P = .68), or C difficile infections (0.04% versus 0%, P = .99) within 90 days in rPCNA patients who received cefazolin versus alternative perioperative antibiotics. CONCLUSIONS: In this series of more than 5,500 patients who had an rPCNA undergoing primary TJA, perioperative prophylaxis with cefazolin resulted in a 0.1% incidence of allergic reactions that were clinically indolent. Cefazolin can be safely administered to most patients, independent of rPCNA severity. LEVEL OF EVIDENCE: III.

Osteoarticular Mycoses.

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Periprosthetic Joint Infection in Patients With Inflammatory Arthritis: Optimal Tests to Differentiate From Flares.

OBJECTIVE: Diagnosis of periprosthetic joint infection (PJI) in patients with inflammatory arthritis (IA) is challenging, as features of IA flares can mimic infection. We aimed to cross-sectionally determine if the optimal tests to diagnose PJI in osteoarthritis were present in patients with IA flares. METHODS: We enrolled patients from October 2020 to July 2022 in 3 groups: (a) PJI-total joint arthroplasty patients undergoing revision for infection, (b) IA Flare-IA patients with a flaring native joint, and (c) IA Aseptic-total joint arthroplasty patients with IA undergoing aseptic arthroplasty revision. We compared blood and synovial fluid markers between the cohorts using Kruskal-Wallis and Fisher exact tests to assess marker sensitivity and specificity. RESULTS: Of 52 cases overall, 40% had rheumatoid arthritis, 20% psoriatic arthritis, and 11% osteoarthritis (in PJI group). PJI cases had higher C-reactive protein (CRP) and synovial fluid polymorphonuclear neutrophil percentage (%PMN). Alpha-defensin tested positive in 93% of PJI cases, 20% of IA Flares, and 6% of IA Aseptic (p < 0.01). Synovial white blood cell count >3000/µL and positive alpha-defensin were highly sensitive (100%) in diagnosing infection; however, specificity was 50% for white blood cell counts and 79% for alpha-defensin. PJI diagnosis was nearly 5 times more likely with positive alpha-defensin and almost 6 times more likely with %PMNs >80. Blood markers interleukin-6, procalcitonin, and d-dimer were neither sensitive nor specific, whereas erythrocyte sedimentation rate and CRP showed 80% sensitivity, but 47% and 58% respective specificities. CONCLUSIONS: Although synovial %PMNs, CRP, and alpha-defensin are sensitive tests for diagnosing PJI, they are less specific and may be positive in IA flares.

Vitamin D and SARS-CoV-2 Infection: SERVE Study (SARS-CoV-2 Exposure and the Role of Vitamin D among Hospital Employees).

BACKGROUND: Recognition of the role of vitamin D in immune function has led to interest in its relationship with SARS-CoV-2 infection. Although clinical studies to date have had conflicting results, many individuals currently take high doses of vitamin D to prevent infection. OBJECTIVE: The goal of this study was to investigate the relationship between serum 25-hydroxyvitamin D (25OHD) and vitamin D supplement use with incident SARS-CoV-2 infection. METHODS: In this prospective cohort study, 250 health care workers were enrolled at a single institution and observed for 15 mo. Participants completed questionnaires every 3 mo regarding new SARS-CoV-2 infection, vaccination, and supplement use. Serum was drawn at baseline, 6, and 12 mo for 25OHD and SARS-CoV-2 nucleocapsid antibodies. RESULTS: The mean age of the participants was 40 y, BMI 26 kg/m2, 71% were Caucasian, and 78% female. Over 15 mo, 56 participants (22%) developed incident SARS-CoV-2 infections. At baseline, ∼50% reported using vitamin D supplements (mean daily dose 2250 units). Mean serum 25OHD was 38 ng/mL. Baseline 25OHD did not predict incident SARS-CoV-2 infection (OR: 0.98; 95% CI: 0.80, 1.20). Neither the use of vitamin D supplements (OR: 1.18; 95% CI: 0.65, 2.14) or supplement dose was associated with incident infection (OR: 1.01 per 100-units increase; 95% CI: 0.99, 1.02). CONCLUSION: In this prospective study of health care workers, neither serum 25OHD nor the use of vitamin D supplements was associated with the incident SARS-CoV-2 infection. Our findings argue against the common practice of consuming high-dose vitamin D supplements for the presumed prevention of COVID-19.

No Difference in the Rate of Periprosthetic Joint Infection in Patients Undergoing the Posterolateral Compared to the Direct Anterior Approach.

BACKGROUND: There remains inconsistent data about the association of surgical approach and periprosthetic joint infection (PJI). We sought to evaluate the risk of reoperation for superficial infection and PJI after primary total hip arthroplasty (THA) in a multivariate model. METHODS: We reviewed 16,500 primary THAs, collecting data on surgical approach and all reoperations within 1 year for superficial infection (n = 36) or PJI (n = 70). Considering superficial infection and PJI separately, we used Kaplan-Meier survivorship to assess survival free from reoperation and a Cox Proportional Hazards multivariate models to assess risk factors for reoperation. RESULTS: Between direct anterior approach (DAA) (N = 3,351) and PLA (N = 13,149) cohorts, rates of superficial infection (0.4 versus 0.2%) and PJI (0.3 versus 0.5%) were low and survivorship free from reoperation for superficial infection (99.6 versus 99.8%) and PJI (99.4 versus 99.7%) were excellent at both 1 and 2 years. The risk of developing superficial infection increased with high body mass index (BMI) (hazard ratio [HR] = 1.1 per unit increase, P = .003), DAA (HR = 2.7, P = .01), and smoking status (HR = 2.9, P = .03). The risk of developing PJI increased with the high BMI (HR = 1.04, P = .03), but not surgical approach (HR = 0.68, P = .3). CONCLUSION: In this study of 16,500 primary THAs, DAA was independently associated with an elevated risk of superficial infection reoperation compared to the PLA, but there was no association between surgical approach and PJI. An elevated patient BMI was the strongest risk factor for superficial infection and PJI in our cohort. LEVEL OF EVIDENCE: III, retrospective cohort study.

2022 American College of Rheumatology/American Association of Hip and Knee Surgeons Guideline for the Perioperative Management of Antirheumatic Medication in Patients With Rheumatic Diseases Undergoing Elective Total Hip or Total Knee Arthroplasty.

OBJECTIVE: To develop updated American College of Rheumatology/American Association of Hip and Knee Surgeons guidelines for the perioperative management of disease-modifying medications for patients with rheumatic diseases, specifically those with inflammatory arthritis (IA) and those with systemic lupus erythematosus (SLE), undergoing elective total hip arthroplasty (THA) or elective total knee arthroplasty (TKA). METHODS: We convened a panel of rheumatologists, orthopedic surgeons, and infectious disease specialists, updated the systematic literature review, and included currently available medications for the clinically relevant population, intervention, comparator, and outcomes (PICO) questions. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology to rate the quality of evidence and the strength of recommendations using a group consensus process. RESULTS: This guideline updates the 2017 recommendations for perioperative use of disease-modifying antirheumatic therapy, including traditional disease-modifying antirheumatic drugs, biologic agents, targeted synthetic small-molecule drugs, and glucocorticoids used for adults with rheumatic diseases, specifically for the treatment of patients with IA, including rheumatoid arthritis and spondyloarthritis, those with juvenile idiopathic arthritis, or those with SLE who are undergoing elective THA or TKA. It updates recommendations regarding when to continue, when to withhold, and when to restart these medications and the optimal perioperative dosing of glucocorticoids. CONCLUSION: This updated guideline includes recently introduced immunosuppressive medications to help decision-making by clinicians and patients regarding perioperative disease-modifying medication management for patients with IA and SLE at the time of elective THA or TKA.

Changes in the kinetics and kinematics of a reactive cut maneuver after successful athletic groin pain rehabilitation.

Athletic groin pain (AGP) is a chronic, painful condition which is prevalent in players of field sports that require rapid changes of direction. Following successful rehabilitation, systematic changes have been observed in the kinetics and kinematics of pre-planned change of direction maneuvers, providing insight into potential foci for rehabilitation monitoring and for the assessment of interventions. However, changing direction in field sports is often reactive rather than pre-planned, and it is not known whether such post-rehabilitation changes are seen in reactive maneuvers. We analyzed the stance phase kinetics and kinematics of a 90° reactive cutting maneuver in 35 AGP patients before and after a successful exercise intervention program. Following the intervention, transverse plane rotation of the pelvis toward the intended direction of travel increased, and the body center of mass was positioned more anteriorly relative to the center of pressure. Ankle dorsiflexion also increased, and participants demonstrated greater ankle plantar flexor internal moment and power during the second half of stance. These findings provide insight into mechanical variables of potential importance in AGP, as identified during a maneuver based on a common sporting task.

Temporary new implant spacers increase post-reimplantation total knee prosthesis survival after periprosthetic joint infection.

PURPOSE: Two-stage exchange arthroplasty is considered the gold standard for treatment of periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). Antibiotic cement spacers can include cement-based spacers (CBS), new components (NEW), and autoclaved components (ACL). The factors that most influence post-reimplantation prosthesis (PRP) survival were determined. METHODS: A retrospective database review of patients undergoing two-stage exchange arthroplasty from 2008 to 2014 was performed. There were 85 patients, 25 patients and 30 patients in CBS, NEW and ACL groups, respectively. Patient, disease and surgical characteristics were collected and analyzed. Post-reimplantation prosthesis (PRP) survival was modeled using the Kaplan-Meier method. Cox proportional hazard modeling was then performed to identify risk factors associated with implant failure. RESULTS: Overall PRP survival was 82% in 140 unilateral TKAs. PRP survival between groups was 81%, 96% and 73% within the minimum 2-year follow-up period, respectively. There was a difference in median interval-to-reimplantation between groups (CBS, 72.0 days; NEW, 111.0 days; ACL, 84.0 days, p = 0.003). Adjusting for time-to-reimplantation, NEW spacers demonstrated greater PRP survival compared with ACL spacers (p = 0.044), and a trend towards greater survival compared with CBS spacers (p = 0.086). Excluding early failures (< 90 days), NEW spacers still demonstrated greater survival than ACL spacers (p = 0.046). Lower volume (≤ 10 within this series) surgeons tended to use more CBS spacers, while higher volume surgeons were comfortable with ACL spacers. CONCLUSIONS: There was greater PRP survival with NEW spacers. NEW spacers also demonstrated an increased inter-stage interval, likely because of increased comfort and motion. There were spacer choice differences between low- and high-volume surgeons. LEVEL OF EVIDENCE: III.

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.

Accuracy of Predictive Algorithms in Total Hip and Knee Arthroplasty Acute Periprosthetic Joint Infections Treated With Debridement, Antibiotics, and Implant Retention (DAIR).

BACKGROUND: Debridement, antibiotics, and implant retention (DAIR) failure remains high for total hip and knee arthroplasty periprosthetic joint infection (PJI). We sought to determine the predictive value of the CRIME80 and KLIC for failure of DAIR in acute hematogenous (AH) and acute postoperative (AP) PJIs, respectively. METHODS: We identified 134 patients who underwent DAIR for AH PJI with <4 weeks of symptoms after index arthroplasty and 122 patients who underwent DAIR for AP PJI <90 days from index. In the AH group, 15 patients (11%) failed at 90 days and overall, 33 (25%) had failed by 2 years. In the AP group, 39 (32%) failed at 90 days and overall, 52 (43%) failed by 2 years. Logistic regression models were used to determine the area under the curve (AUC) to establish thresholds using the Youden index. RESULTS: For the AP cohort, AUCs were below 0.66 for KLIC, Charlson comorbidity index, Elixhauser comorbidity index, and McPherson host grade. For the AH cohort, 90-day AUCs were 0.70 for CRIME80 and below 0.66 for Charlson comorbidity index, Elixhauser comorbidity index, and McPherson host grade. In multivariate analysis controlling for age, sex, and body mass index, the CRIME80 AUC improved to 0.77 at 90 days. CONCLUSION: To the authors' knowledge, this study represents the first external validation of the KLIC and CRIME80 for predicting DAIR failure in a North American population. The results indicate that alternative methods for predicting DAIR failure at 90 days and 2 years for acute PJI are needed. LEVEL OF EVIDENCE: Prognostic III.

Principal Component Analysis of the Biomechanical Factors Associated With Performance During Cutting.

ABSTRACT: Welch, N, Richter, C, Franklyn-Miller, A, and Moran, K. Principal component analysis of the biomechanical factors associated with performance during cutting. J Strength Cond Res 35(6): 1715-1723, 2021-The main aim of the current study was to investigate the relationship between kinematic variables in cutting and performance outcome across different angled cuts through the use of principal component analysis and permutation testing. Twenty-five male intercounty Gaelic football players (23.5 ± 4.2 years, 183 ± 6 cm, and 83 ± 6.9 kg) participated in the study. Three-dimensional motion capture was used to perform a biomechanical analysis of 110 and 45° cutting tasks. Principal component analysis and permutation testing revealed one principal component within the 45° cut (r = 0.26) and 2 principal components within the 110° (r = 0.66 and 0.27) cut that consistently correlated with performance outcome. Within the 45° cut, the identified principal component was interpreted as relating to performance cues of maintaining a low center of mass during the concentric phase, using a shorter ground contact time, resisting a reduction in lateral center of mass to ankle and knee distance in the eccentric phase, and using faster and larger extensions of the hip and knee. Within the 110° cut, the first identified principal component was interpreted as relating to performance cues of maintaining a low center of mass during the concentric phase, using a shorter ground contact time, resisting a reduction in lateral center of mass to ankle and knee distance in the eccentric phase, and resisting hip flexion then using hip extension. The second principal component was interpreted as relating to a performance cue of leaning in the direction of the cut.

Principal Component Analysis of the Associations Between Kinetic Variables in Cutting and Jumping, and Cutting Performance Outcome.

ABSTRACT: Welch, N, Richter, C, Moran, K, and Franklyn-Miller, A. Principal component analysis of the associations between kinetic variables in cutting and jumping, and cutting performance outcome. J Strength Cond Res 35(7): 1848-1855, 2021-The primary aim of this study was to determine which features within the ground reaction force (GRF) trace during cutting are related to performance outcome in different angled cuts. The secondary aim was to understand the relationship between GRF features in a series of maximum strength, explosive strength, and reactive strength tests, and cutting performance outcome. Twenty-five male intercounty Gaelic football players (23.5 ± 4.2 years, 183 ± 6 cm, and 83 ± 6.9 kg) participated in the study. Subjects completed 110 and 45° cutting tasks, single leg squat jumps, drop landings, drop jumps, and isometric midthigh pulls. A principal component (PC) analysis and simulation approach were applied to the data and correlations between PCs and cutting performance outcome measured. Lower vertical to horizontal impulse ratios (r = -0.70 to -0.46) in both cuts and greater forces over the first 50 ms of ground contact (r = -0.44) in the 110° cut correlated with enhanced cutting performance outcomes. Greater reactive strength index and height in the drop jump (r = -0.51 and -0.54) and greater impulses over the first 25 ms of ground contact in the drop landing (r = 0.49 and 0.70) correlated with enhanced cutting performance outcomes. These results highlight the importance of greater horizontal and rapid force production in cutting and greater reactive strength qualities to enhance cutting performance.

The Role of Long-Term Antibiotic Suppression in the Management of Peri-Prosthetic Joint Infections Treated With Debridement, Antibiotics, and Implant Retention: A Systematic Review.

BACKGROUND: A number of clinical trials have been conducted, assessing the role of long-term (>1 year) suppressive antibiotic treatment (SAT) combined with Debridement, Antibiotics, and Implant Retention (DAIR) for the management of peri-prosthetic joint infection (PJI). However, no systematic review of the literature has been published to date to evaluate complications associated with long-term antibiotic treatment and overall survivorship free from re-operation and revision for infection after DAIR for total hip and total knee PJI. METHODS: The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications from January 1980 to December 2018 utilizing keywords pertinent to total knee arthroplasty, total hip arthroplasty, PJI, and antibiotic suppression. RESULTS: Overall, 7 articles of low quality (level III or IV) were included in this analysis. The studies included in this systematic review included 437 cases of PJI treated surgically with DAIR and then with SAT. The overall mean infection-free rate of SAT following DAIR was 75% (318/424 patients), while the all-cause re-operation rate was 6.7%. Overall, the mean rate of adverse effects associated with long-term antibiotic use was 15.4% and the mean rate of adverse effects leading to discontinuation of SAT was 4.3%. There was no study to show significant differences between acute (either post-operative or hematogenous, with onset of symptoms ≤4 weeks) and chronic (onset of symptoms >4 weeks) infections and failure rates of DAIR with SAT. The literature is inconclusive on the influence of anatomic location (hip vs knee) as well as microorganism on the success rate of DAIR with SAT. CONCLUSION: The results of this systematic review demonstrate that there is still only low-quality evidence regarding the therapeutic effect of DAIR combined with SAT, which is not enough to draw definitive conclusions. Furthermore, high-quality prospective studies are needed to better understand SAT's efficacy and safety in a controlled fashion. Although discontinuation of antibiotic treatment due to side effects was found to be low, the high rates of adverse effects noted after DAIR with SAT demonstrate the underlying frailty and complexity of many patients with PJI, and the imperfect therapies available. Although Staphylococcus aureus appears to be a risk factor for increased risk of SAT failure, there are not enough data to establish which patients would benefit most from DAIR with post-operative SAT.

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.

Treatment and Outcome of Periprosthetic Joint Infection in Unicompartmental Knee Arthroplasty.

BACKGROUND: Periprosthetic joint infection (PJI) after unicompartmental knee arthroplasty (UKA) is a devastating but poorly understood complication, with a paucity of published data regarding treatment and outcomes. This study analyzes the largest cohort of UKA PJIs to date comparing treatment outcome, septic and aseptic reoperation rates, and risk factors for treatment failure. METHODS: Twenty-one UKAs in 21 patients treated for PJI, as defined by Musculoskeletal Infection Society criteria, were retrospectively reviewed. Minimum and mean follow-up was 1 and 3.5 years, respectively. Fourteen (67%) patients had acute postoperative PJIs. Surgical treatment included 16 debridement, antibiotics, and implant retentions (DAIRs) (76%), 4 two-stage revisions (19%), and 1 one-stage revision (5%). Twenty (95%) PJIs were culture positive with Staphylococcus species identified in 15 cases (71%). RESULTS: Survivorship free from reoperation for infection at 1 year was 76% (95% confidence interval, 58%-93%). Overall survival from all-cause reoperation was 57% (95% confidence interval, 27%-87%) at 5 years. Two additional patients (10%) underwent aseptic revision total knee arthroplasty for lateral compartment degeneration 1 year after DAIR and tibial aseptic loosening 2.5 years after 2-stage revision. All patients who initially failed PJI UKA treatment presented with acute postoperative PJIs (5 of 14; 36%). CONCLUSION: Survivorship free from persistent PJI at 1 year is low at 76% but is consistent with similar reports of DAIRs for total knee arthroplasties. Furthermore, there is low survivorship free from all-cause reoperation of 71% and 57% at 2 and 5 years, respectively. Surgeons should be aware of these poorer outcomes and consider treating UKA PJI early and aggressively.

Increased Staphylococcus aureus Nasal Carriage Rates in Rheumatoid Arthritis Patients on Biologic Therapy.

BACKGROUND: Rheumatoid arthritis patients are at increased risk for periprosthetic joint infection after arthroplasty. The reason is multifactorial. Nasal colonization with Staphylococcus aureus is a modifiable risk factor; carriage rates in RA patients are unknown. The goal of this study is to determine the S aureus nasal carriage rates of RA patients on biologics, RA patients on traditional disease-modifying anti-rheumatic drugs (DMARDs), and osteoarthritis. METHODS: Consecutive patients with RA on biologics (±DMARDs), RA on non-biologic DMARDs, or OA were prospectively enrolled from April 2017 to May 2018. One hundred twenty-three patients were determined necessary per group to show a difference in carriage rates. Patients underwent a nasal swab and answered questions to identify additional risk factors. S aureus positive swabs were further categorized using spa typing. Logistic regression evaluated the association with S aureus colonization between the groups after controlling for known risk factors. RESULTS: RA patients on biologics, 70% of whom were on DMARDs, had statistically significant increase in S aureus colonization (37%) compared to RA on DMARDs alone (24%), or OA (20%) (P = .01 overall). After controlling for glucocorticoids, antibiotic use, recent hospitalization, and diabetes, RA on biologics had a significant increased risk of S aureus nasal colonization (Odds ratio 1.80, 95% confidence interval 1.00-3.22, P = .047). CONCLUSION: S aureus colonization risk was increased for RA on biologics compared to RA not on biologics and OA. Nasal S aureus carriage increases the risk of surgical site infection; this modifiable risk factor should be addressed prior to total joint arthroplasty for this higher risk patient group.

Whole-body biomechanical differences between limbs exist 9 months after ACL reconstruction across jump/landing tasks.

INTRODUCTION: Previous studies examining jump tasks after anterior cruciate ligament reconstruction (ACLR) have focused on performance measures without examining joint kinematic and kinetic variables. The aim of this study was to identify differences in biomechanical and performance measures between limbs across tests 9 months after surgery. METHODS: Four jump tests (double-leg drop jump (DLDJ), single-leg drop jump (SLDJ), single-leg hop for distance (SLHD) and hurdle hop (HH)) were carried out on 156 male subjects in a 3D motion capture laboratory 9 months after surgery. Statistical parametric mapping was used to identify differences in jump performance and biomechanical variables between limbs. RESULTS: Biomechanical measures were lower on the ACLR side across all four tests for internal knee valgus moment (effect size 0.78-0.96, knee internal rotation angle 0.59-0.73, and 0.60-0.83), respectively. [corrected].The timing of the largest difference between limbs was not at the same % stance between variables within a test or for any variable across tests. Large ES differences were observed in performance in the SLDJ (ES 0.73-0.81; LSI 78%) and small differences in the SLHD (ES 0.36; LSI 94%) between the limbs. CONCLUSION: Findings highlighted biomechanical differences between limbs which are consistent across jump tasks suggesting insufficient rehabilitation at 9 months post surgery. Results indicate that the SLDJ may identify greater performance deficits between limbs than SLHD, which may over-estimate rehabilitation status.

Cost-Effectiveness of Staphylococcus aureus Decolonization Strategies in High-Risk Total Joint Arthroplasty Patients.

BACKGROUND: The risk of prosthetic joint infection increases with Staphylococcus aureus colonization. The cost-effectiveness of decolonization is controversial. We evaluated cost-effectiveness decolonization protocols in high-risk arthroplasty patients. METHODS: An analytical model evaluated risk under 3 protocols: 4 swabs, 2 swabs, and nasal swab alone. These were compared to no-screening and universal decolonization strategies. Cost-effectiveness was evaluated from the hospital, patient, and societal perspective. RESULTS: Under base case conditions, universal decolonization and 4-swab strategies were most effective. The 2-swab and universal decolonization strategy were most cost-effective from patient and societal perspectives. From the hospital perspective, universal decolonization was the dominant strategy (much less costly and more effective). CONCLUSION: S aureus decolonization may be cost-effective for reducing prosthetic joint infections in high-risk patients. These results may have important implications for treatment of patients and for cost containment in a bundled payment system.

Clinical Analysis of Propionibacterium acnes Infection After Total Knee Arthroplasty.

BACKGROUND: Propionibacterium acnes is a common cause of upper extremity arthroplasty infection and usually presents in an indolent subacute fashion. It is not well described how total knee arthroplasty (TKA) patients infected with P acnes present. METHODS: We retrospectively compared patients undergoing revision TKA for infection from P acnes and methicillin-sensitive Staphylococcal aureus (MSSA) in our institutional infection database. Patients were classified as having a periprosthetic joint infection based on the Musculoskeletal Infection Society criteria and were excluded if they had a polymicrobial culture. Patient demographics, preoperative laboratory values, microbiology data, and synovial fluid white blood cell (WBC) counts were analyzed. RESULTS: Sixteen patients with a P acnes and 30 with an MSSA TKA periprosthetic joint infection were identified. Median erythrocyte sedimentation rate was significantly higher in the MSSA group compared to the P acnes group (56.0 mm/h; interquartile range [IQR], 44.3-72.9 vs 23.0 mm/h; IQR, 18.5-52.0; respectively, P = .03) as were C-reactive protein levels (5.9 mg/dL; IQR, 3.7-26.9 vs 2.0 mg/dL; IQR, 0.5-14.0; respectively, P = .04). WBC count, synovial fluid WBC, and percentage of synovial polymorphonuclear cells were similar between groups. Mean time to culture was 8.3 ± 2.0 days in the P acnes group and 1.8 ± 0.8 days in the MSSA group. CONCLUSION: P acnes TKA infections are associated with more acute inflammatory symptoms than typically appreciated, and long hold anaerobic cultures up to 14 days are necessary to accurately identify this organism as the causative agent of TKA periprosthetic infection.

Travel-associated disease among US residents visiting US GeoSentinel clinics after return from international travel.

BACKGROUND: US residents make 60 million international trips annually. Family practice providers need to be aware of travel-associated diseases affecting this growing mobile population. OBJECTIVE: To describe demographics, travel characteristics and clinical diagnoses of US residents who present ill after international travel. METHODS: Descriptive analysis of travel-associated morbidity and mortality among US travellers seeking care at 1 of the 22 US practices and clinics participating in the GeoSentinel Global Surveillance Network from January 2000 to December 2012. RESULTS: Of the 9624 ill US travellers included in the analysis, 3656 (38%) were tourist travellers, 2379 (25%) missionary/volunteer/research/aid workers (MVRA), 1580 (16%) travellers visiting friends and relatives (VFRs), 1394 (15%) business travellers and 593 (6%) student travellers. Median (interquartile range) travel duration was 20 days (10-60 days). Pre-travel advice was sought by 45%. Hospitalization was required by 7%. Compared with other groups of travellers, ill MVRA travellers returned from longer trips (median duration 61 days), while VFR travellers disproportionately required higher rates of inpatient care (24%) and less frequently had received pre-travel medical advice (20%). Illnesses of the gastrointestinal tract were the most common (58%), followed by systemic febrile illnesses (18%) and dermatologic disorders (17%). Three deaths were reported. Diagnoses varied according to the purpose of travel and region of exposure. CONCLUSIONS: Returning ill US international travellers present with a broad spectrum of travel-associated diseases. Destination and reason for travel may help primary health care providers to generate an accurate differential diagnosis for the most common disorders and for those that may be life-threatening.