Does antibiotic bone cement reduce infection rates in primary total knee arthroplasty?

INTRODUCTION: Infection after total knee arthroplasty (TKA) impacts the patient, surgeon, and healthcare system significantly. Surgeons routinely use antibiotic-loaded bone cement (ALBC) in attempts to mitigate infection; however, little evidence supports the efficacy of ALBC in reducing infection rates compared to non-antibiotic-loaded bone cement (non-ALBC) in primary TKA. Our study compares infection rates of patients undergoing TKA with ALBC to those with non-ALBC to assess its efficacy in primary TKA. METHODS: A retrospective review of all primary, elective, cemented TKA patients over the age of 18 between 2011 and 2020 was conducted at an orthopedic specialty hospital. Patients were stratified into two cohorts based on cement type: ALBC (loaded with gentamicin or tobramycin) or non-ALBC. Baseline characteristics and infection rates determined by MSIS criteria were collected. Multilinear and multivariate logistic regressions were performed to limit significant differences in demographics. Independent samples t test and chi-squared test were used to compare means and proportions, respectively, between the two cohorts. RESULTS: In total, 9366 patients were included in this study, 7980 (85.2%) of whom received non-ALBC and 1386 (14.8%) of whom received ALBC. There were significant differences in five of the six demographic variables analyzed; patients with higher Body Mass Index (33.40 ± 6.27 vs. 32.09 ± 6.21; kg/m2) and Charlson Comorbidity Index values (4.51 ± 2.15 vs. 4.04 ± 1.92) were more likely to receive ALBC. The infection rate in the non-ALBC was 0.8% (63/7,980), while the rate in the ALBC was 0.5% (7/1,386). After adjusting for confounders, the difference in rates was not significant between the two groups (OR [95% CI]: 1.53 [0.69-3.38], p = 0.298). Furthermore, a sub-analysis comparing the infection rates within various demographic categories also showed no significant differences between the two groups. CONCLUSION: Compared to non-ALBC, the overall infection rate in primary TKA was slightly lower when using ALBC; however, the difference was not statistically significant. When stratifying by comorbidity, use of ALBC still showed no statistical significance in reducing the risk of periprosthetic joint infection. Therefore, the advantage of antibiotics in bone cement to prevent infection in primary TKA is not yet elucidated. Further prospective, multicenter studies regarding the clinical benefits of antibiotic use in bone cement for primary TKA are warranted.

Trends in Complications and Outcomes in Patients Aged 65 Years and Younger Undergoing Total Hip Arthroplasty: Data From the American Joint Replacement Registry.

This study sought to determine common complications and the rates of readmission and revision in total hip arthroplasty patients younger than 65 years. Using the American Joint Replacement Registry, we conducted a retrospective review of all THAs in patients aged 18 to 65 years from 2012 to 2020. We excluded patients aged older than 65 years, revisions, oncologic etiology, conversion from prior surgery, and nonelective cases. Primary outcomes included cumulative revision rate, 90-day readmission rate, and reason for revision. The Kaplan-Meier method and univariate analysis were used. Five thousand one hundred fifty-three patients were included. The average age was 56.7 years (SD 7.8 years), 51% were female, 85% were White, and 89% had a Charlson Comorbidity Index of 0 (1 = 7%, >2 = 4%). The mean follow-up was 39.57 months. Fifty-three patients (1.0%) underwent revision. Seventy-four patients (1.4%) were readmitted within 90 days. Revision was more common in Black patients (P = 0.023). Survivorship was 99% (95% confidence interval, 98.7 to 99.3) and 99% (95% confidence interval, 98.5 to 99.3) at 5 and 8 years, respectively. Infection (21%), instability (15%), periprosthetic fracture (15%), and aseptic loosening (9%) were the most common indications for revision. Total hip arthroplasty performed in young and presumed active patients had a 99% survivorship at 8 years. A long-term follow-up is needed to evaluate survival trends in this growing population.

Patellar Component Design Does Not Impact Clinical Outcomes in Primary Total Knee Arthroplasty.

BACKGROUND: Round or oval implants are used in patellar resurfacing during total knee arthroplasty (TKA). However, whether component geometry affects clinical outcomes is unclear. This study aimed to determine if one implant shape conferred superior outcomes to the other. METHODS: A retrospective review of primary TKA cases performed from 2016 to 2020 was conducted at an urban, tertiary academic center. Four hundred consecutive, primary TKAs were included in these analyses. Cases were included if a surgeon used the round design then oval design for fifty consecutive cases. Baseline demographic data and radiographic measurements were assessed. Surgical data, reasons for revision, and patient-reported outcome measures were analyzed. Independent samples t-test and chi-square tests were used to compare means and proportions. There were no demographic differences between the cohorts. RESULTS: Postoperative patellar tilt was statistically different between the cohorts. Sixteen patients required revision surgery; however, revision rates did not differ between the cohorts. Of the 9 rounds, 1 button was revised for infection. Of the 7 ovals, 1 button was revised for infection and 1 for loosening. Veterans RAND 12 Physical Component Score at 3 months postoperatively was higher for the round cohort, but no differences were observed at 1 year. CONCLUSION: While radiographic patellar tilt was significantly different between the cohorts, there was no clinical correlation in outcomes at 3 months or 1 year postoperatively. Longer-term follow-up studies are needed to evaluate the implications of patellar component design on outcomes and function. Nevertheless, the current study affirms that both designs are clinically equivalent which should be used to guide clinical decision-making. LEVEL III EVIDENCE: Retrospective Cohort.

Streamlining orthopaedic trauma surgical care: do all patients need medical clearance?

INTRODUCTION: Preoperative medical optimization is necessary for safe and efficient care of the orthopaedic trauma patient. To improve care quality and value, a preoperative matrix was created to more appropriately utilize subspecialty consultation and avoid unnecessary consults, testing, and operating room delays. Our study compares surgical variables before and after implementation of the matrix to assess its utility. METHODS: A retrospective review of all orthopaedic trauma cases 6 months before and after the use of the matrix (2/2021-8/2021) was conducted an urban, level one trauma centre in collaboration with internal medicine, cardiology, anaesthesia, and orthopaedics. Patients were separated into two cohorts based on use of the matrix during the initial orthopaedic consultation. Logistic regressions were performed to limit significant differences in comorbidities. Independent samples t-tests and Chi-squared tests were used to compare means and proportions, respectively, between the two cohorts. RESULTS: In total, 576 patients were included in this study (281 pre- and 295 post-matrix implementation). Use of the matrix resulted in no significant difference in time to OR, LOS, readmissions, or ER visits; however, it resulted in 18% fewer overall preoperative consults for general trauma, and 25% fewer pre-operative consults for hip fractures. Older patients were more likely to require a consult regardless of matrix use. When controlling for comorbidities, patients with renal disease were at higher risk for increased LOS. CONCLUSION: Use of an orthopaedic surgical matrix to predict preoperative subspecialty consultation is easy to implement and allows for better care utilization without a corresponding increase in complications and readmissions. Follow-up studies are needed to reassess the relationships between matrix use and a potential decrease in ER to OR time, and validate its use.

Intraoperative technology increases operating room times in primary total knee arthroplasty.

INTRODUCTION: Optimization of patient outcomes and identification of factors to improve the surgical workflow are increasingly important. Operating room time is one modifiable factor that leads to greater hospital efficiency as well as improved outcomes such as shorter length of stay and fewer infections and readmissions. The aim of this study was to identify factors associated with operative time disparities in total knee arthroplasty (TKA). METHODS: A retrospective review of 7659 consecutive primary TKA cases was conducted. Patient demographic data, discrete operating room (OR) times, use of technology (i.e. robotic-assisted surgery, computer navigation), surgeon experience and the level of training of the first assistant were collected. Multivariate regression analysis was used to determine the effect of hospital characteristics on operative times. Operative times of five minutes or greater were considered to be clinically significant. RESULTS: While the use of technology (182.64 ± 39.85 vs 158.70 ± 37.45 min; B = 26.09; p < 0.0001) and greater surgeon experience (162.14 ± 39.87 vs 158.69 ± 33.18 min, B = 3.15, p = 0.002) were found to increase OR times, level of training of the first assist (161.65 vs 156.4 min; Β = - 0.264; p = 0.487) did not. Of the discrete OR times examined, incision time and total time under anesthesia were negatively impacted by the use of technology. CONCLUSION: Use of technology was the only study variable found to significantly increase OR times. With increased operative times and limited evidence that technology improves long-term patient outcomes, surgeons should carefully consider the benefits and cost of technology in TKA.

Trends in Complications and Outcomes in Patients Aged 65 Years and Younger Undergoing Total Knee Arthroplasty: Data From the American Joint Replacement Registry.

INTRODUCTION: The purpose of this study was to identify common complications and the rates of readmission and revision in total knee arthroplasty (TKA) patients younger than 65 years. METHODS: Using the American Joint Replacement Registry, we conducted a retrospective review of all TKAs done in patients aged 18 to 65 years from 2012 to 2020. Demographic factors such as age, sex, Charlson Comorbidity Index (CCI), and preoperative Veterans RAND 12-Item Health Survey Physical Component Summary (VR-12 PCS) scores were collected. We excluded patients older than 65 years and revision, oncologic, and nonelective cases. Primary outcomes included cumulative revision rate, 90-day readmission rate, and reason for revision. Univariate analysis and the Kaplan-Meier method were used. RESULTS: Six thousand one hundred seventy-nine patients were included. The average age was 58.8 years (SD 5.5 years), 61% were female, 82% were White, and 88% had a CCI of 0 (1 = 8% and ≥2 = 4%). The mean follow-up was 42.51 months. Seventy-four patients (1.2%) underwent revision. Sixty-nine patients (1.1%) were readmitted within 90 days. No factors assessed increased revision rates. Revision-free survivorship was 98.7% (95% CI 98.4 to 99.0) and 98.6% (95% CI 98.2 to 99.0) at 5 and 8 years, respectively. Infection (15%), aseptic loosening (14%), and instability (12%) were the most common indications for revision. CONCLUSION: TKA done in young and presumed active patients has excellent survivorship. Long-term follow-up is needed to assess survival trends in this growing population.

Validation of Single-Outcome Questionnaire in Primary TKA and THA.

BACKGROUND: Patient-reported outcome measures can be used to evaluate post-operative health care quality and patient satisfaction. The Patient's Joint Perception (PJP) question gathers a single patient-reported outcome to measure how patients appraise their joint. This study compares PJP to the Forgotten Joint Score (FJS) at 21 months post-operation to assess its value. METHODS: A retrospective review was performed at an orthopedic specialty hospital for patients who completed both PJP and FJS questionnaires in 2020-2021 and underwent either a unilateral elective primary Total Knee Arthroplasty (TKA) or Total Hip Arthroplasty (THA). Spearman's correlation coefficients and P-values were calculated to determine external validity of PJP. Floor and ceiling effects were analyzed and considered present if ≥ 15% of patients achieved the worst or best score (0-4 for PJP and 0-100 for FJS). RESULTS: In total, 534 patients (327 THA and 207 TKA) were surveyed at 21 months post-operation. External validity against FJS was assessed for both TKA (r = 0.66, P < .01) and THA (r = 0.69, P < .01). For TKA, the floor and ceiling effects were 0.97% and 25.12% for PJP and 3.86% and 4.83% for FJS, respectively. For THA, the floor and ceiling effects were 0.92% and 50.46% for PJP and 2.47% and 20.50% for FJS, respectively. CONCLUSION: The PJP was correlated with FJS moderately for both TKA and THA and can be collected with lesser burden. However, ceiling effects were higher in both TKA and THA for PJP compared to FJS. Further studies are needed to investigate the questionnaires at additional time points and to evaluate the implications of high ceiling effects.

Diagnosis of Leptomeningeal Metastasis in Women With Breast Cancer Through Identification of Tumor Cells in Cerebrospinal Fluid Using the CNSide™ Assay.

INTRODUCTION: Diagnosis of LM is limited by low sensitivity of cerebrospinal fluid (CSF) cytopathology. Detecting tumor cells in CSF (CSF-TCs) might be more sensitive. We evaluated if CNSide (CNSide), a novel assay for tumor cell detection in CSF, can detect CSF-TCs better than conventional CSF cytology. METHODS: We enrolled adults with metastatic breast cancer and clinical suspicion for LM to undergo lumbar puncture (LP) for CSF cytopathology and CNSide. CNSide captured CSF-TCs using a primary 10-antibody mixture, streptavidin-coated microfluidic channel, and biotinylated secondary antibodies. CSF-TCs were assessed for estrogen receptor (ER) expression by fluorescent antibody and HER2 amplification by fluorescent in situ hybridization (FISH). CSF cell-free DNA (cfDNA) was extracted for next-generation sequencing (NGS). Leptomeningeal disease was defined as positive CSF cytology and/or unequivocal MRI findings. We calculated sensitivity and specificity of CSF cytology and CNSide for the diagnosis of LM. RESULTS: Ten patients, median age 51 years (range, 37-64), underwent diagnostic LP with CSF evaluation by cytology and CNSide. CNSide had sensitivity of 100% (95% Confidence Interval [CI], 40%-100%) and specificity of 83% (95% CI, 36%-100%) for LM. Among these patients, concordance of ER and HER2 status between CSF-TCs and metastatic biopsy were 60% and 75%, respectively. NGS of CSF cfDNA identified somatic mutations in three patients, including one with PIK3CA p.H1047L in blood and CSF. CONCLUSIONS: CNSide may be a viable platform to detect CSF-TCs, with potential use as a diagnostic tool for LM in patients with metastatic breast cancer. Additional, larger studies are warranted.

ERK1/2 phosphorylation predicts survival following anti-PD-1 immunotherapy in recurrent glioblastoma.

Only a subset of recurrent glioblastoma (rGBM) responds to anti-PD-1 immunotherapy. Previously, we reported enrichment of BRAF/PTPN11 mutations in 30% of rGBM that responded to PD-1 blockade. Given that BRAF and PTPN11 promote MAPK/ERK signaling, we investigated whether activation of this pathway is associated with response to PD-1 inhibitors in rGBM, including patients that do not harbor BRAF/PTPN11 mutations. Here we show that immunohistochemistry for ERK1/2 phosphorylation (p-ERK), a marker of MAPK/ERK pathway activation, is predictive of overall survival following adjuvant PD-1 blockade in two independent rGBM patient cohorts. Single-cell RNA-sequencing and multiplex immunofluorescence analyses revealed that p-ERK was mainly localized in tumor cells and that high-p-ERK GBMs contained tumor-infiltrating myeloid cells and microglia with elevated expression of MHC class II and associated genes. These findings indicate that ERK1/2 activation in rGBM is predictive of response to PD-1 blockade and is associated with a distinct myeloid cell phenotype.