Cellular Diversity in Human Subgenual Anterior Cingulate and Dorsolateral Prefrontal Cortex by Single-Nucleus RNA-Sequencing.

Regional cellular heterogeneity is a fundamental feature of the human neocortex; however, details of this heterogeneity are still undefined. We used single-nucleus RNA-sequencing to examine cell-specific transcriptional features in the dorsolateral PFC (DLPFC) and the subgenual anterior cingulate cortex (sgACC), regions implicated in major psychiatric disorders. Droplet-based nuclei-capture and library preparation were performed on replicate samples from 8 male donors without history of psychiatric or neurologic disorder. Unsupervised clustering identified major neural cell classes. Subsequent iterative clustering of neurons further revealed 20 excitatory and 22 inhibitory subclasses. Inhibitory cells were consistently more abundant in the sgACC and excitatory neuron subclusters exhibited considerable variability across brain regions. Excitatory cell subclasses also exhibited greater within-class transcriptional differences between the two regions. We used these molecular definitions to determine which cell classes might be enriched in loci carrying a genetic signal in genome-wide association studies or for differentially expressed genes in mental illness. We found that the heritable signals of psychiatric disorders were enriched in neurons and that, while the gene expression changes detected in bulk-RNA-sequencing studies were dominated by glial cells, some alterations could be identified in specific classes of excitatory and inhibitory neurons. Intriguingly, only two excitatory cell classes exhibited concomitant region-specific enrichment for both genome-wide association study loci and transcriptional dysregulation. In sum, by detailing the molecular and cellular diversity of the DLPFC and sgACC, we were able to generate hypotheses on regional and cell-specific dysfunctions that may contribute to the development of mental illness.SIGNIFICANCE STATEMENT Dysfunction of the subgenual anterior cingulate cortex has been implicated in mood disorders, particularly major depressive disorder, and the dorsolateral PFC, a subsection of the PFC involved in executive functioning, has been implicated in schizophrenia. Understanding the cellular composition of these regions is critical to elucidating the neurobiology underlying psychiatric and neurologic disorders. We studied cell type diversity of the subgenual anterior cingulate cortex and dorsolateral PFC of humans with no neuropsychiatric illness using a clustering analysis of single-nuclei RNA-sequencing data. Defining the transcriptomic profile of cellular subpopulations in these cortical regions is a first step to demystifying the cellular and molecular pathways involved in psychiatric disorders.

Robotic-assisted total knee arthroplasty is associated with the use of thinner polyethylene liners compared to navigation-guided and manual techniques.

PURPOSE: The purpose of this study was to examine the effects of intraoperative technology use on the rate of using polyethylene liners 15 mm or greater during primary total knee arthroplasty (TKA). METHODS: There were 103,295 implants from 16,386 primary unilateral TKAs performed on 14,253 patients at a single institution between 1 January 2018, and 30 June 2022, included in the current study. Robotic assistance and navigation guidance were used in 1274 (8%) and 8345 (51%) procedures, respectively. The remaining 6767 TKAs (41%) were performed manually. Polyethylene liners were manually identified and further subcategorised by implant thickness. Patients who underwent robotic-assisted TKA were younger (p < 0.001) and more likely to be male (p < 0.001) compared to patients who underwent navigation-guided or manual TKAs. RESULTS: Average polyethylene liner thickness was similar between groups (10.5 ± 1.5 mm for robotic-assisted TKAs, 10.9 ± 1.8 mm for navigation-guided TKAs and 10.8 ± 1.8 mm for manual TKAs). The proportions of polyethylene liners 15 mm or greater used were 4.9%, 3.8% and 1.9% for navigation-guided, manual and robotic-assisted procedures, respectively (p < 0.001). Multivariate regression analyses demonstrated that navigation-guided (odds ratio [OR]: 2.6, 95% confidence Interval [CI]: [1.75-4.07], p < 0.001) and manual (OR: 2.0, 95% CI: [1.34-3.20], p = 0.001) procedures were associated with an increased use of polyethylene liners 15 mm or greater. CONCLUSION: Robotic-assisted TKA was associated with a lower proportion of polyethylene liners 15 mm or greater used compared to navigation-guided and manual TKA. These findings suggest that robotic assistance can reduce human error via a more precise cutting system, limit over-resection of the tibia and flexion-extension gap mismatch and ultimately allow for more appropriately sized implants. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Timing of Renal Transplant Prior to Total Knee Arthroplasty Impacts 90-Day Postoperative Outcomes.

BACKGROUND: Renal transplant (RT) patients are at increased risk for complications after total knee arthroplasty (TKA); however, it is unknown if the time from RT to TKA influences such risks. This study evaluated RT patients undergoing primary TKA at various time intervals after transplant. We hypothesized that increased time between RT and TKA would decrease the risk of complications after TKA. METHODS: There were 499 RT patients in a national database undergoing subsequent primary TKA from 2010 to 2020. Patients were stratified by intervals of less than 1 year, between 1 and 2 years, and more than 2 years from RT to TKA. Medical complications up to 90 days, readmissions, and 2-year revisions were compared via univariable and multivariable analyses. RESULTS: Patients who underwent TKA less than 1 year after RT were associated with higher 90-day medical complications when compared to those who underwent TKA 1 to 2 years after RT (odds ratio [OR] 0.4, confidence interval [CI] 0.2 to 0.8, P = .01) and more than 2 years (OR 0.3, CI 0.2 to 0.7, P < .01) after RT. Acute kidney injury and blood transfusion were the most common complications. The TKAs performed 2 years after RT were less likely to have 90-day readmissions when compared to TKAs performed less than 1 year after RT (OR 0.4, CI: 0.2 to 0.9, P < .01). However, time from RT to TKA did not increase the risk of revision at 2 years (P > .30). CONCLUSIONS: Patients undergoing TKA within 1 year of RT have an increased risk of 90-day postoperative medical complications and readmissions, but the time interval from RT does not appear to affect revision risk. These findings suggest waiting 1 year after RT before proceeding with TKA may be advantageous.

Inertial Sensor Gait Analysis of Trendelenburg Gait in Patients Who Have Hip Osteoarthritis.

BACKGROUND: Gait abnormalities such as Trendelenburg gait (TG) in patients who have hip osteoarthritis (OA) have traditionally been evaluated using clinicians' visual assessment. Recent advances in portable inertial gait sensors offer more sensitive, quantitative methods for gait assessment in clinical settings. This study sought to compare sensor-derived metrics in a cohort of hip OA patients when stratified by clinical TG severity. METHODS: There were 42 patients who had hip OA and were grouped by TG severity (mild, moderate, and severe) through visual assessment by a single arthroplasty surgeon who had > 30 years of experience. After informed consent, wireless inertial sensors placed at the midpoint of the intercristal line collected gait parameters including pelvic shift, support time, toe-off symmetry, impact, and cadence. Clinical data on hip strength, range of motion, and Kellgren-Lawrence grade were collected. RESULTS: Worsening TG severity had a higher mean Kellgren-Lawrence grade (2.5 versus 3.2 versus 3.4; P = .014) and reduced passive hip abduction (P = .004). Severe TG group demonstrated predominantly contralateral pelvic shift (n = 9 of 10, 90.0%), while ipsilateral shift was more frequently detected in moderate (n = 10 of 18, 55.6%) and mild groups (n = 9 of 14, 64.3%; P = .021). Contralateral single support time bias was greatest in severe TG (35.7% versus 50.0 versus 90.0%; P = .027). Asymmetric toe-off, impact, and support times were observed in all groups. CONCLUSIONS: Traditional understanding of TG is that truncal shift occurs to the ipsilateral side. Using sensor-based measurements, the present study demonstrates a shift of the weight-bearing axis toward the contralateral side with increasing TG severity, which has not been previously described. Inertial sensors are feasible, quantitative gait measuring tools, and may reveal subtle patterns not readily discernible by traditional methods.

The Posterior Approach is Associated With Lower Total Encounter and 90-Day Costs When Compared to the Direct Anterior Approach.

BACKGROUND: The clinical impact of the surgical approach in total hip arthroplasty (THA) has been widely reviewed. This study evaluated the total encounter and 90-day costs of THA for 2 surgical approaches (posterior [P] and direct anterior [DA]) in 1 tertiary health system. METHODS: This is a retrospective review of 2,101 THAs (1,092 P and 1,009 DA) by 4 surgeons (2 with the highest volume of DA and P, respectively) from 2017 to 2022 at 1 academic center. Demographics, comorbidities, operative time, length of hospital stay, 90-day hospital returns, and complications were compared. The total encounter cost and 90-day postoperative cost were itemized. Multivariable regression analyses evaluated associations with increased cost at each time point. RESULTS: The DA cohort had a higher median encounter cost ($8,348.66 versus 7,332.42, P < .01), resulting from higher intraoperative (P < .01) and radiology (P < .01) expenses. Regression analyses demonstrated the DA was independently associated with increased encounter costs (odds ratio 1.1; 95% confidence interval 1.1 to 1.1; P < .01). There was a higher incidence of 90-day emergency department visits in the DA cohort (16 versus 12%, P = .02), with a trend toward increased readmissions. There was no difference in 90-day reoperations. Median 90-day cost was higher in the DA cohort ($126.99 versus 0.00, P < .01), and regression analyses demonstrated the DA had an association with increased 90-day cost (odds ratio 2.2; 95% confidence interval 1.5 to 3.0; P < .01). CONCLUSIONS: Despite a younger patient population, the DA was independently associated with increased encounter and 90-day costs in a single academic hospital system. This study may underestimate the cost difference, as capital costs such as specialized tables were not analyzed.

Ultracongruent Polyethylene Liners Do Not Affect Survival of Total Knee Arthroplasty for Valgus Deformity.

BACKGROUND: Valgus knee deformity is observed in nearly 10% of patients undergoing total knee arthroplasty (TKA). The degree of polyethylene constraint required to balance a valgus knee remains controversial, and historically, posterior-stabilized (PS) designs have been favored. This study evaluated the survivorship of TKA done in valgus knees based on implant design and specifically compared posterior-stabilized (PS) and ultracongruent (UC) liners. METHODS: A total of 549 primary TKAs performed on valgus knees by fellowship-trained arthroplasty surgeons from 2013 to 2019 were reviewed. Demographics, comorbidities, degrees of preoperative deformity, implants used, and all-cause revisions until final follow-up were recorded. Cox regression analyses evaluated survival to all-cause revision in each cohort. The mean follow-up was 4.9 years (range, 2 to 9). RESULTS: There were 403 UC liners compared to 146 PS liners. There was no difference in patient age (68 versus 67 years; P = .30), body mass index (30.9 versus 30.4; P = .36), or degree of deformity (8.6 versus 8.8 degrees; P = .75) between the cohorts. At final follow-up, there were 5 revisions in the PS cohort (3.4%) versus 11 revisions in the UC cohort (2.7%) (P = .90). The most common reason for revision in both cohorts was periprosthetic joint infection (4 PS; 8 UC). Multivariable regression analyses controlling for age, body mass index, Elixhauser comorbidity score, sex, and degree of deformity demonstrated UC polyethylene liners were not associated with revision (hazard ratio 0.76; 95% confidence interval [CI] 0.26 to 2.21; P = .62). There was no difference in eight-year survivorship to all-cause revision, including aseptic and septic failure. CONCLUSIONS: Alternative polyethylene liners from the historically utilized PS liners for TKA for valgus deformity did not reduce survivorship. With modern polyethylene designs, UC inserts can be utilized for this deformity without increasing the risk of failure.

Revision Total Knee Arthroplasty With an Imageless, Second-Generation Robotic System.

BACKGROUND: Robotic-assisted total knee arthroplasty is increasingly used in revision total knee arthroplasty (rTKA), with imageless systems recently receiving Food and Drug Administration (FDA) approval. However, there remains a paucity of literature on the use of robotic assistance in revision total knee arthroplasty (TKA). This paper describes the imageless surgical technique for robotic revision TKA using a second-generation robotic system and details both intraoperative and 90-day outcomes. METHODS: This was a retrospective review of 115 robotic revision TKAs from March 2021 to May 2023 at 3 tertiary academic centers. Patient demographics, perioperative surgical data, and 90-day outcomes were collected. Pain and Patient-Reported Outcomes Measurement Information System scores preoperatively and postoperatively were recorded. All-cause reoperations at the final follow-up were detailed. The mean patient age was 65 years (range, 43 to 88), and 58% were women. The mean follow-up time was 13 months (range, 3 to 51). RESULTS: The most common indications for rTKA were instability (n = 37, 32%) and aseptic loosening (n = 42, 37%). There were 83 rTKAs to a posterior-stabilized liner, 22 to a varus-valgus constrained liner, and 5 to a hinged construct. The median polyethylene size was 11 (interquartile range, 10 to 13), and 93% of patients had their joint line restored within 5 millimeters of the native contralateral knee. Within the 90-day postoperative window, there were 8 emergency department visits and 2 readmissions. At the final follow-up, there were 5 reoperations and 2 manipulations under anesthesia. There were 4 patients who required irrigation and debridement after superficial wound dehiscence, and one had an arthrotomy disruption after a fall. CONCLUSIONS: This review demonstrates favorable intraoperative and 90-day outcomes and suggests that imageless robotic surgery is a promising modality in rTKA. Further studies comparing the longitudinal outcomes after robotic and conventional rTKA are warranted.

D-Dimer, Erythrocyte Sedimentation Rate, and C-Reactive Protein Sensitivities for Periprosthetic Joint Infection Diagnosis.

BACKGROUND: There is contradicting evidence on the diagnostic value of inflammatory biomarkers for periprosthetic joint infection (PJI). We sought to quantify the sensitivity of D-dimer for acute and chronic PJI diagnosis and evaluate D-dimer lab values in the 90-day postoperative window in a control cohort of primary joint arthroplasty patients for comparison. METHODS: An institutional database was queried for patients undergoing revision procedures for PJI after total hip arthroplasty (THA) and total knee arthroplasty (TKA) from 2014 to present. CRP, ESR, and D-dimer were collected within 90 days pre and postoperatively and sensitivities for the diagnosis of PJI were calculated. The control group included patients who underwent a negative diagnostic workup for deep venous thrombosis (DVT) or pulmonary embolus (PE) and had a D-dimer lab collected within 90 days postoperatively from primary total joint arthroplasty (TJA). RESULTS: A total of 604 PJI patients were identified, and 81 patients had D-dimer, ESR, and CRP collected. There were 50/81 acute PJI patients and 31/81 chronic PJI patients who had median D-dimer values of 2,136.5 ng/mL [interquartile range (IQR): 1,642-3,966.5] and 3,336 ng/mL [IQR: 1,976-5,594]. Only the chronic PJI group had significantly higher D-dimer values when compared to the control cohort (P = .009). The sensitivity of D-dimer was calculated to be 92% and 93.5% in the acute and chronic PJI groups, respectively. CONCLUSION: Serum D-dimer may not have high diagnostic utility for acute PJI, especially in the setting of recent surgery; however, it still may be useful for patients who have chronic PJI.

Cost Drivers in Two-Stage Treatment of Hip Periprosthetic Joint Infection With an Antibiotic Coated Cement Hip Spacer.

BACKGROUND: The current gold standard for treating chronic Periprosthetic Joint Infection (PJI) is a 2-stage revision arthroplasty. There has been little investigation into what specific patient and operative factors may be able to predict higher costs of this treatment. METHODS: An institutional electronic health record database was retrospectively queried for patients who developed a PJI after a total hip arthroplasty, and underwent removal of the prosthesis and implantation of an antibiotic-impregnated articulating hip cement spacer. Patient demographics, surgical variables, hospital readmissions, emergency department visits, and post-operative complications were collected. Total costs were captured through an internal accounting database through 2 years post-operatively. Negative binomial regressions were utilized for multivariable analyses. A total of 55 hips with PJI were available for cost analyses. RESULTS: A comorbidity index score was associated with a 70% increase (Odds Ratio (OR): 1.7 [1.18-2.5], P = .003) in total costs at 2-years. Illicit drug use was associated with a 70% increase in costs at 1-year post-operatively (OR 1.7 [1.18-2.5], P = .003). Metal-on-poly liners were associated with a 22% decrease in cost at 2-years post-operatively when compared to Cement-on-Bone articulating spacers, and Metal-on-poly -constrained liners accounted for 38% lower costs at 1-year (OR 0.62 [0.44-0.87], P = .004). Use of an intraoperative extended trochanteric osteotomy was associated with a 46 and 61% increase in cost at 1-year (OR 1.46 [1.14-1.89]) and 2-years (OR 1.61 [1.26-2.07], P < .001) post-operatively. CONCLUSION: Age, comorbidity index score, drug use, and extended trochanteric osteotomy were associated with increased costs of PJI treatment. This may be used to improve reimbursement models and target areas of cost savings.

Accelerated Discharge After Aseptic Revision Total Hip Arthroplasty Does Not Predict Inferior 30-Day Outcomes.

BACKGROUND: Perioperative advancements have made outpatient primary total hip arthroplasty (THA) a viable option for patients. This study evaluated the feasibility of expedited discharge after revision THA and compared 30-day outcomes to patients who had prolonged inpatient hospitalizations. The authors hypothesized that expedited discharge would not result in inferior 30-day outcomes. METHODS: Aseptic revision THAs in a national database were reviewed from 2013 to 2020. THAs were stratified by hospital length of stay (LOS) more or less than 24 hours. Demographics, comorbidities, preoperative laboratory values, American Society of Anesthesiology (ASA) scores, operative times, components revised, 30-day readmissions, and reoperations were compared. Multivariable analyses evaluated predictors of discharge prior to 24 hours, 30-day readmissions, and reoperations. Of 17,044 aseptic revision THAs, 211 were discharged within 24 hours. RESULTS: Accelerated discharge patients were younger, mean age 63 years (range, 20-92) versus 66 years (range, 18-94) (P < .01) had lower body mass index, mean 28.7 (range, 18.3-46.4) versus 29.9 (range, 17.3-52.5) (P = .01), and ASA scores (ASA, 1-2; 40.4-57.8%) (P < .01). Components revised had no association with LOS (P = .39); however, operative times were shorter and mean 100 minutes (range, 35-369) versus 139 minutes (range, 24-962) (P < .01) in accelerated discharge patients. Accelerated discharge patients had lower readmission rates (P < .01) but no difference in reoperation rates (P = .06). CONCLUSION: Discharge less than 24 hours after revision THA is a feasible option for the correct patient and further efforts to decrease LOS should be evaluated.

The Removal of Total Hip Arthroplasty From the Inpatient-Only List has Improved Patient Selection and Expanded Optimization Efforts.

BACKGROUND: On January 1, 2020, the Centers for Medicare and Medicaid Services removed total hip arthroplasty (THA) from the Inpatient-Only (IPO) list. This study evaluated patient demographics and comorbidities, preoperative optimization efforts, and 30-day outcomes of patients undergoing outpatient THA before and after IPO removal. The authors hypothesized that patients undergoing THA post-IPO removal would have improved optimization of modifiable risk factors and equivalent 30-day outcomes. METHODS: There were 17,063 outpatient THAs in a national database stratified by surgery performed before (2015 to 2019: 5,239 patients) and after IPO (2020: 11,824 patients) removal. Demographics, comorbidities, and 30-day outcomes were compared with univariable and multivariable analyses. Preoperative optimization thresholds were established for the following modifiable risk factors: albumin, creatinine, hematocrit, smoking history, and body mass index. The percentage of patients who fell outside the thresholds in each cohort were compared. RESULTS: Patients undergoing outpatient THA post-IPO removal were significantly older; mean age 65 years (range, 18 to 92) versus 62 (range, 18 to 90) years (P < .01), with a higher percentage of American Society of Anesthesiologists scores 3 and 4 (P < .01). There was no difference in 30-day readmissions (P = .57) or reoperations (P = 1.00). A significantly lower percentage of patients fell outside the established threshold for albumin (P < .01) post-IPO removal, and trended towards lower percentages for hematocrit and smoking status. CONCLUSION: The removal of THA from the IPO list expanded patient selection for outpatient arthroplasty. Preoperative optimization is critical to minimize postoperative complications, and the current study demonstrates that 30-day outcomes have not worsened post-IPO removal.

A Permanent Articulating Spacer Versus Two-Stage Exchange for Chronic Periprosthetic Joint Infection: A Propensity Score-Matched Study.

BACKGROUND: Although 2-stage revision has been proposed as gold standard for periprosthetic joint infection treatment, limited evidence exists for the role of articulating spacers as definitive management. The purpose of this study was to compare clinical outcomes and costs associated with articulating spacers (1.5-stage) and a matched 2-stage cohort. METHODS: A retrospective review was performed for patients who had chronic periprosthetic joint infections after total knee arthroplasty defined by Musculoskeletal Infection Society criteria and were matched via propensity score matching using cumulative Musculoskeletal Infection Society scores and a comorbidity index. Patients who maintained an articulating spacer (cemented cobalt-chrome femoral component and all-poly tibia) were included in the 1.5-stage cohort. Patients who underwent a 2-stage reimplantation procedure were included in the 2-stage cohort. Outcomes included visual analog scale pain scores, 90-day emergency department visits, 90-day readmission, unplanned reoperation, reinfection, as well as cost at 1 and 2-year intervals. A total of 116 patients were included for analyses. RESULTS: The 90-day pain scores were lower in the 1.5-stage cohort compared to the 2-stage cohort (2.9 versus 4.6, P = .0001). There were no significant differences between readmission and reoperation rates. Infection clearance was equivalent at 79.3% for both groups. Two-stage exchange demonstrated an increased cost difference of $26,346 compared to 1.5-stage through 2 years (P = .0001). Regression analyses found 2 culture-positive results with the same organism decreased the risk for reinfection [odds ratio: 0.2, 95% confidence interval 0.04-0.8, P = .03]. CONCLUSION: For high-risk candidates, articulating spacers can preserve knee function, reduce morbidity from second-stage surgery, and lower the costs with similar rates of infection clearance as 2-stage exchange. LEVEL OF EVIDENCE: Level III, therapeutic study.

Does Order of Operation Matter in Patients Who Have Concomitant Hip and Spine Pathology?

BACKGROUND: In patients, who have coexisting lumbar spine and degenerative hip disease, there remains uncertainty regarding whether hip or spine surgery should be performed first. We hypothesized that undergoing total hip arthroplasty (THA) would protect against subsequent lumbar spine surgery (LSS) in patients who have 'hip-spine syndrome.' METHODS: A retrospective cohort study was performed from 2013 to 2021 on patients who had radiographically-confirmed hip osteoarthritis and degenerative lumbar spine pathology, evaluated separately in spine and arthroplasty clinics prior to surgical intervention. Included patients ultimately underwent THA and/or LSS. The primary outcome was survivorship free of LSS or THA after the other was initially performed. RESULTS: Of 256 patients, 206 (80.5%) underwent THA first. Only 14 of 206 (6.8%) who underwent THA required subsequent LSS, while 31 of 50 (62%) who underwent LSS required subsequent THA, (P < .001). At 5 years, there was 93.9% survivorship-free of LSS in the THA first group, compared to 44.7% survivorship-free of subsequent THA in the LSS group. Multivariate analyses showed that patients who had THA first had lower odds of undergoing subsequent surgery (odds ratio [OR]: 0.61, CI: 0.52-0.70, P < .001) compared to those who underwent LSS first. Additionally, those who have higher initial Kellgren-Lawrence grade hip osteoarthritis had lower odds (OR: 0.94, CI: 0.89-0.99, P = .04), and those who have progressive neurologic deficits (OR: 2.64, CI: 1.89-3.7, P < .001) and neurogenic claudication (OR: 1.15, CI: 1.06-1.24, P = .001) had increased odds of undergoing subsequent LSS. CONCLUSION: Patients with 'hip-spine syndrome' may receive more initial benefit from undergoing THA, potentially reducing the subsequent need for LSS. The exceptions were those patients who had lower-severity hip osteoarthritis and symptoms of major spinal stenosis.

Robotic Technology in Foot and Ankle Surgery: A Comprehensive Review.

Recent developments in robotic technologies in the field of orthopaedic surgery have largely been focused on higher volume arthroplasty procedures, with a paucity of attention paid to robotic potential for foot and ankle surgery. The aim of this paper is to summarize past and present developments foot and ankle robotics and describe outcomes associated with these interventions, with specific emphasis on the following topics: translational and preclinical utilization of robotics, deep learning and artificial intelligence modeling in foot and ankle, current applications for robotics in foot and ankle surgery, and therapeutic and orthotic-related utilizations of robotics related to the foot and ankle. Herein, we describe numerous recent robotic advancements across foot and ankle surgery, geared towards optimizing intra-operative performance, improving detection of foot and ankle pathology, understanding ankle kinematics, and rehabilitating post-surgically. Future research should work to incorporate robotics specifically into surgical procedures as other specialties within orthopaedics have done, and to further individualize machinery to patients, with the ultimate goal to improve perioperative and post-operative outcomes.

Cutibacterium positive cultures in total joint arthroplasty: a comparison of the hip, knee, and shoulder.

PURPOSE: Cutibacterium spp. (formerly Propionibacterium) is a slow growing, Gram-positive, anaerobic bacteria and is an emerging clinical entity in prosthetic joint infection (PJI). This study compares the presentation, surgical management, and post-operative antibiotic therapy of patients with positive intraoperative cultures during revision total joint arthroplasty (TJA) of the hip, knee, and shoulder. METHODS: This was a retrospective cohort study of patients from 2014 to 2020 of 57 revision TJAs (27 total hip arthroplasty (THA), 17 total shoulder arthroplasty (TSA), and 13 total knee arthroplasty (TKA)) with intraoperative cultures positive for Cutibacterium at a tertiary academic centre. Patient demographics, pre-operative labs, radiographs, and aspirate results were collected. Intraoperative data was reviewed. Post-operative antibiotic therapy and repeat infections were recorded. Data was compared with univariate analyses. RESULTS: There was no significant difference in pre-operative lab values between the cohorts. All cohorts had > 58% radiographic lucency. Revision TSA patients had significantly fewer pre-operative aspirates. Six patients undergoing revision THA, three TKA and one TSA had a repeat infection requiring further surgery. Four in the THA cohort and one in the TKA cohort with repeat infections did not receive prolonged antibiotic therapy. CONCLUSION: Cutibacterium is an infectious agent that can present in an indolent fashion after TJA. It commonly causes progressive radiographic lucency. The workup and post-operative management differs in the hip, knee, and shoulder, which is likely due to existing literature guiding physician practice. In all joints, Cutibacterium is a virulent pathogen that can cause repeat infections requiring surgical treatment.

Number of Months of Baseball in the Previous Year and Preseason Olecranon Tenderness: Risk Factors for Shoulder and Elbow Injuries in High-School Baseball Players.

OBJECTIVE: To identify risk factors for shoulder and elbow injuries in high-school baseball position players and pitchers in the preseason history and physical examination. DESIGN: Retrospective cohort study. SETTING: Community high-school baseball. PARTICIPANTS: Three hundred seventy-one male baseball players' mean age 15.0 ± 1.8 years. OUTCOME MEASURES: A preseason history and physical examination was performed on all athletes. Injury information was collected by weekly self-report and athletic trainer injury logs throughout the season. Comparisons between injured and noninjured players were performed using t tests and χ 2 analyses. Binary logistic regression models were developed to identify risk factors for injury. RESULTS: Seventy-six injuries were recorded over the season. In univariate analysis, the injured group had greater months of baseball participation ( P = 0.007) and shoulder visual analog scale for the past year ( P = 0.003). The injured group also had more olecranon tenderness ( P < 0.0001, odds ratio [OR] 2.9) and decreased elbow arc of motion. All other factors were not significantly different ( P > 0.05). In multivariable logistic regression, months per year of baseball participation was the only factor significantly associated with injuries ( P = 0.010, OR = 1.21). CONCLUSIONS: Baseball players who developed arm injuries during a season were more likely to play more months of baseball and report shoulder pain in the previous year. The presence of preseason olecranon tenderness was associated with nearly triple the risk of injury during the season. Every additional month of baseball participation in the previous year was associated with a 1.2× increased odds of injury. The presence of glenohumeral internal rotation deficit was not a predictor of injury.

Comparison of computed tomography and 3D magnetic resonance imaging in evaluating glenohumeral instability bone loss.

BACKGROUND: To determine whether the addition of 3-dimensional (3D) magnetic resonance imaging (MRI) to standard MRI sequences is comparable to 3D computed tomographic (CT) scan evaluation of glenoid and humeral bone loss in glenohumeral instability. METHODS: Eighteen patients who presented with glenohumeral instability were prospectively enrolled and received both MRI and CT within 1 week of each other. The MRI included an additional sequence (volumetric interpolated breath-hold examination [VIBE]) that underwent postprocessing for reformations. The addition of a VIBE protocol, on average, is an additional 4-4.5 minutes in the scanner. CT data also underwent 3D postprocessing, and therefore each patient had 4 imaging modalities (2D CT, 2D MRI, 3D CT reformats, and 3D MRI reformats). Each sequence underwent the following measurements from 2 separate reviewers: glenoid defect, glenoid defect percentage, humeral defect, humeral defect percentage, and evaluation of glenoid track and version. Paired t tests were used to assess differences between imaging modalities and χ2 for glenoid track. Intra- and interobserver reliability were evaluated. Bland-Altman tests were also performed to assess the agreement between CT and MRI. In addition, we determined the cost of each imaging modality at our institution. RESULTS: 3D MRI measurements for glenoid and humeral bone loss measurements were comparable to 3D CT (Table 1). There were no significant differences for glenoid defect size and percentage, or humeral defect size and percentage (P > .05) (Table 2). Bland-Altman analysis demonstrated strong agreement, with small measurement errors for 3D CT and 3D MRI percentage glenoid bone loss. There was also no difference in evaluation for determining on vs. off track between any of the imaging modalities. Inter- and intrarater reliability was good to excellent for all CT and MRI measurements (r ≥ 0.7). CONCLUSION: 3D MRI measurements for bone loss in glenohumeral instability through use of VIBE sequence were equivalent to 3D CT. At our institution, undergoing MRI with 3D reconstruction was 1.67 times cheaper than MRI and CT with 3D reconstructions. 3D MRI may be a useful adjuvant to standard MRI sequences to allow concurrent soft tissue and accurate assessment of glenoid and humeral bone loss in glenohumeral instability.

Cutibacterium Positive Cultures in Total Hip Arthroplasty: Contaminant or Pathogen?

BACKGROUND: Cutibacterium spp. is an emerging pathogen in total hip arthroplasty (THA) that is not well evaluated in the literature. This study reported on the presentation and management of THA complicated by positive intraoperative Cutibacterium cultures. METHODS: This is a retrospective review of 27 revision THAs with positive monomicrobial intraoperative Cutibacterium cultures from 2014 to 2020 at one academic center. These patients were divided into two cohorts based on meeting Musculoskeletal Infection Society (MSIS) criteria for prosthetic joint infections (PJI). Patient demographics, preoperative labs, and hip aspirate results were collected. Procedure performed, postoperative antibiotic regimens, and repeat infections were recorded. Data were compared with univariate analysis. RESULTS: Nine of the 27 patients preoperatively met MSIS criteria for PJI. Patients with positive MSIS criteria had significantly higher median synovial cell count (P = .048) and neutrophil percentage in a preoperative aspirate (P = .050). Eight patients with positive MSIS criteria received six weeks of postoperative antibiotics compared to two patients with negative criteria. Two patients with positive MSIS criteria had a postoperative infection that required further surgical intervention. Four patients with negative criteria who required further surgical intervention did not receive postoperative antibiotics after initial revision. CONCLUSION: While often categorized as a contaminant, Cutibacterium is an increasingly recognized pathogen in THA. Cutibacterium can often present with normal serology, which may result in misdiagnosis as aseptic THA failure. Without the administration of postoperative antibiotics after positive cultures, there is a risk for persistent infection requiring further surgical intervention.

Patterns and Predictors of Weight Change Before and After Total Hip Arthroplasty in Class 2 and 3 Obese Patients.

BACKGROUND: This study aimed to better understand body mass index (BMI) change patterns and factors associated with BMI change before and after total hip arthroplasty (THA) in Class 2 and 3 obese patients, and assess if preoperative or postoperative BMI change affects postoperative clinical outcomes. METHODS: We retrospectively reviewed World Health Organization Class 2 and 3 obese patients (BMI > 35.0 at surgery) who underwent THA at a tertiary medical center from 2010 to 2020. BMI was recorded at 1 year preoperatively (mean 11.6 months), and at most recent postoperative visit (mean 29.0 months). Baseline demographics and postoperative clinical outcomes were recorded. RESULTS: We reviewed 436 THAs with a mean age of 59.9 (11.5) years. Leading up to surgery 55.5% had unchanged BMI, and postoperatively 48.2% had unchanged BMI. Multivariate logistic regression revealed that those who lost BMI preoperatively were more likely to gain BMI postoperatively (odds ratio [OR] 3.28, confidence interval [CI] 1.83-5.97, P = .005), but those who gained >5% BMI preoperatively had no association with BMI change postoperatively. Those in a higher BMI class preoperatively were less likely to gain BMI preoperatively (Class 3 obese patients: OR 0.001, CI 0.0002-0.004, P < .001). African American patients were more likely to gain BMI preoperatively (OR 2.32, CI 1.16-4.66, P = .017). We did not detect an association between BMI change and postoperative clinical outcomes. CONCLUSION: In World Health Organization Class 2 or 3 obese patients, most maintained BMI between their first preoperative and final postoperative visit. Preoperatively, Class 3 obese patients were less likely to gain weight than Class 2 obese patients. The primary predictor of postoperative weight gain was preoperative weight loss. Weight change preoperatively and postoperatively were not associated with worse clinical outcomes.

Clinical Outcomes After Stage-One Antibiotic Coated Molded Hip Spacer.

BACKGROUND: Two-stage exchange remains the gold standard for managing periprosthetic joint infection (PJI). We evaluated the outcomes of patients treated with a specific molded articulating antibiotic hip spacer for PJI at a tertiary referral center. METHODS: An institutional database was retrospectively queried for patients who underwent implantation of spacer between 2009-2019. Patient demographics and clinical outcomes were collected. RESULTS: We identified 88 patients at an average age of 60.4 years who received a spacer implant, with an average of 4.2 years follow-up (standard deviation [SD] 2.5 years). A total of 34 patients (38.6%) had a "clean" two-stage course with successful reimplantation and no evidence of infection at 1-year follow-up. The remaining patients (61.4%) required 3.67 (±0.52) additional surgeries. Overall reimplantation rate was 72%. Causative bacterial agents included MSSA (n = 22), MRSA (n = 16), coagulase-negative Staphylococcus (n = 14), and polymicrobial (n = 12). Regarding complications, there were 13 (15%) dislocations, 16 (18%) periprosthetic fractures, 8 (9%) bent/fractured stems, and 16 (18%) patients had clinically significant subsidence. Patients with previous extended trochanteric osteotomy (ETO) experienced higher rates of bent/broken spacer stems (25% vs 3.1%; P = .006) periprosthetic fractures (37.5% vs 10.9%; P = .010), and dislocations (37.5% vs 6.2%; P = .001). The rate of infection clearance was lower in the prior ETO cohort (26.6% vs 54.2%; P = .029). CONCLUSION: We report outcomes in patients who underwent implantation of a specific molded articulating hip spacer at our institution. Infection eradication was roughly in line with published series of hip PJI treatment. There was a high rate of mechanical complications, especially in those patients who required an ETO.