Deep learning applications for quantitative and qualitative PET in PET/MR: technical and clinical unmet needs.

We aim to provide an overview of technical and clinical unmet needs in deep learning (DL) applications for quantitative and qualitative PET in PET/MR, with a focus on attenuation correction, image enhancement, motion correction, kinetic modeling, and simulated data generation. (1) DL-based attenuation correction (DLAC) remains an area of limited exploration for pediatric whole-body PET/MR and lung-specific DLAC due to data shortages and technical limitations. (2) DL-based image enhancement approximating MR-guided regularized reconstruction with a high-resolution MR prior has shown promise in enhancing PET image quality. However, its clinical value has not been thoroughly evaluated across various radiotracers, and applications outside the head may pose challenges due to motion artifacts. (3) Robust training for DL-based motion correction requires pairs of motion-corrupted and motion-corrected PET/MR data. However, these pairs are rare. (4) DL-based approaches can address the limitations of dynamic PET, such as long scan durations that may cause patient discomfort and motion, providing new research opportunities. (5) Monte-Carlo simulations using anthropomorphic digital phantoms can provide extensive datasets to address the shortage of clinical data. This summary of technical/clinical challenges and potential solutions may provide research opportunities for the research community towards the clinical translation of DL solutions.

Do ChatGPT and Gemini Provide Appropriate Recommendations for Pediatric Orthopaedic Conditions?

BACKGROUND: Artificial intelligence (AI), and in particular large language models (LLMs) such as Chat Generative Pre-Trained Transformer (ChatGPT) and Gemini have provided additional resources for patients to research the management of healthcare conditions, for their own edification and the advocacy in the care of their children. The accuracy of these models, however, and the sources from which they draw conclusions, have been largely unstudied in pediatric orthopaedics. This research aimed to assess the reliability of machine learning tools in providing appropriate recommendations for the care of common pediatric orthopaedic conditions. METHODS: ChatGPT and Gemini were queried using plain language generated from the American Academy of Orthopaedic Surgeons (AAOS) Clinical Practice Guidelines (CPGs) listed on the Pediatric Orthopedic Society of North America (POSNA) web page. Two independent reviewers assessed the accuracy of the responses, and chi-square analyses were used to compare the 2 LLMs. Inter-rater reliability was calculated via Cohen's Kappa coefficient. If research studies were cited, attempts were made to assess their legitimacy by searching the PubMed and Google Scholar databases. RESULTS: ChatGPT and Gemini performed similarly, agreeing with the AAOS CPGs at a rate of 67% and 69%. No significant differences were observed in the performance between the 2 LLMs. ChatGPT did not reference specific studies in any response, whereas Gemini referenced a total of 16 research papers in 6 of 24 responses. 12 of the 16 studies referenced contained errors and either were unable to be identified (7) or contained discrepancies (5) regarding publication year, journal, or proper accreditation of authorship. CONCLUSION: The LLMs investigated were frequently aligned with the AAOS CPGs; however, the rate of neutral statements or disagreement with consensus recommendations was substantial and frequently contained errors with citations of sources. These findings suggest there remains room for growth and transparency in the development of the models which power AI, and they may not yet represent the best source of up-to-date healthcare information for patients or providers.

Extended Prophylactic Antibiotics for Primary and Aseptic Revision Total Joint Arthroplasty: A Meta-Analysis.

BACKGROUND: There is growing interest in extended antibiotic prophylaxis (EAP) following total joint arthroplasty (TJA); however, the benefit of EAP remains controversial. For this investigation, both oral and intravenous antibiotic protocols were included in the EAP group. METHODS: The Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, PubMed, MEDLINE, Web of Science, Ovid Embase, Elton B. Stephens CO, and Cumulative Index to Nursing and Allied Health Literature were queried for literature comparing outcomes of primary and aseptic revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients who were treated with either ≤24 hours of postoperative antibiotic prophylaxis (standard of care [SoC]) or >24 hours of EAP. The primary outcome was periprosthetic joint infection (PJI). A pooled relative-risk random-effects Mantel-Haenszel model was implemented to compare cohorts. RESULTS: There were 18 studies with a total of 19,153 patients included. There was considerable variation in antibiotic prophylaxis protocols with first-generation cephalosporins being the most commonly implemented antibiotic for both groups. Patients treated with EAP were 35% less likely to develop PJI relative to the SoC (P = .0004). When examining primary TJA, patients treated with EAP were 39% and 40% less likely to develop a PJI for TJA (P = .0008) and THA (P = .02), respectively. There was no significant difference for primary TKA (P = .17). When examining aseptic revision TJA, EAP led to a 36% and 47% reduction in the probability of a PJI for aseptic revision TJA (P = .007) and aseptic revision TKA (P = .008), respectively; there was no observed benefit for aseptic revision THA (P = .36). CONCLUSIONS: This meta-analysis demonstrated that patients treated with EAP were less likely to develop a PJI relative to those treated with the SoC for all TJA, primary TJA, primary THA, aseptic revision TJA, and aseptic revision TKA. There was no significant difference observed between EAP and SoC for primary TKA or aseptic revision THA.

Chat Generative Pretrained Transformer (ChatGPT) and Bard: Artificial Intelligence Does not yet Provide Clinically Supported Answers for Hip and Knee Osteoarthritis.

BACKGROUND: Advancements in artificial intelligence (AI) have led to the creation of large language models (LLMs), such as Chat Generative Pretrained Transformer (ChatGPT) and Bard, that analyze online resources to synthesize responses to user queries. Despite their popularity, the accuracy of LLM responses to medical questions remains unknown. This study aimed to compare the responses of ChatGPT and Bard regarding treatments for hip and knee osteoarthritis with the American Academy of Orthopaedic Surgeons (AAOS) Evidence-Based Clinical Practice Guidelines (CPGs) recommendations. METHODS: Both ChatGPT (Open AI) and Bard (Google) were queried regarding 20 treatments (10 for hip and 10 for knee osteoarthritis) from the AAOS CPGs. Responses were classified by 2 reviewers as being in "Concordance," "Discordance," or "No Concordance" with AAOS CPGs. A Cohen's Kappa coefficient was used to assess inter-rater reliability, and Chi-squared analyses were used to compare responses between LLMs. RESULTS: Overall, ChatGPT and Bard provided responses that were concordant with the AAOS CPGs for 16 (80%) and 12 (60%) treatments, respectively. Notably, ChatGPT and Bard encouraged the use of non-recommended treatments in 30% and 60% of queries, respectively. There were no differences in performance when evaluating by joint or by recommended versus non-recommended treatments. Studies were referenced in 6 (30%) of the Bard responses and none (0%) of the ChatGPT responses. Of the 6 Bard responses, studies could only be identified for 1 (16.7%). Of the remaining, 2 (33.3%) responses cited studies in journals that did not exist, 2 (33.3%) cited studies that could not be found with the information given, and 1 (16.7%) provided links to unrelated studies. CONCLUSIONS: Both ChatGPT and Bard do not consistently provide responses that align with the AAOS CPGs. Consequently, physicians and patients should temper expectations on the guidance AI platforms can currently provide.

Strikingly High Rates of Periprosthetic Joint Infection Following Revision Surgery for Periprosthetic Fractures Regardless of Surgery Timing.

BACKGROUND: Periprosthetic fractures following total hip arthroplasty (THA) often occur in the early postoperative period. Recent data has indicated that early revisions are associated with higher complication rates, particularly periprosthetic joint infection (PJI). The purpose of this study was to assess the effect of timing of periprosthetic fracture surgery on complication rates. We hypothesized that complication rates would be significantly higher in revision surgeries performed within 3 months of the index THA. METHODS: The Medicare Part A claims database was queried from 2010 to 2017 to identify patients who underwent surgery for a periprosthetic fracture following primary THA. Patients were divided based on time between index and revision surgeries: <1, 1 to 2, 2 to 3, 3 to 6, 6 to 9, 9 to 12, and >12 months. Complication rates were compared between groups using multivariate analyses to adjust for demographics, comorbidities, and types of revision surgery. RESULTS: Of 492,340 THAs identified, 4,368 (0.9%) had a subsequent periprosthetic fracture requiring surgery: 1,725 (39.4%) at <1 month, 693 (15.9%) at 1 to 2 months, 202 (4.6%) at 2 to 3 months, 250 (5.7%) at 3 to 6 months, 134 (3.1%) at 6 to 9 months, 85 (19.4%) at 9 to12 months, and 1,279 (29.3%) at >12 months. The risk of PJI was 11.0% in the <1 month group, 11.1% at 1 to 2 months, 7.9% at 2 to 3 months, 6.8% at 3 to 6 months, 8.2% at 6 to 9 months, 9.4% at 9 to 12 months, and 8.5% at >12 months (P = .12). Adjusting for confounding factors, risk of PJI following periprosthetic fracture surgery was similar regardless of timing (P > .05). Rates of subsequent dislocation and aseptic loosening were also similar regardless of timing. CONCLUSIONS: The risk of PJI following repeat surgery for a periprosthetic fracture was strikingly high regardless of timing (6.8 to 11.1%), underscoring the high-risk of complications.

Structural Insights and Catalytic Mechanism of 3-Hydroxybutyryl-CoA Dehydrogenase from Faecalibacterium Prausnitzii A2-165.

Atopic dermatitis (AD) is characterized by a T-helper cell type 2 (Th2) inflammatory response leading to skin damage with erythema and edema. Comparative fecal sample analysis has uncovered a strong correlation between AD and Faecalibacterium prausnitzii strain A2-165, specifically associated with butyrate production. Therefore, understanding the functional mechanisms of crucial enzymes in the butyrate pathway, such as 3-hydroxybutyryl-CoA dehydrogenase of A2-165 (A2HBD), is imperative. Here, we have successfully elucidated the three-dimensional structure of A2HBD in complex with acetoacetyl-CoA and NAD+ at a resolution of 2.2Å using the PAL-11C beamline (third generation). Additionally, X-ray data of A2HBD in complex with acetoacetyl-CoA at a resolution of 1.9 Å were collected at PAL-XFEL (fourth generation) utilizing Serial Femtosecond Crystallography (SFX). The monomeric structure of A2HBD consists of two domains, N-terminal and C-terminal, with cofactor binding occurring at the N-terminal domain, while the C-terminal domain facilitates dimerization. Our findings elucidate the binding mode of NAD+ to A2HBD. Upon acetoacetyl-CoA binding, the crystal structure revealed a significant conformational change in the Clamp-roof domain (root-mean-square deviation of 2.202 Å). Notably, residue R143 plays a critical role in capturing the adenine phosphate ring, underlining its significance in substrate recognition and catalytic activity. The binding mode of acetoacetyl-CoA was also clarified, indicating its lower stability compared to NAD+. Furthermore, the conformational change of hydrophobic residues near the catalytic cavity upon substrate binding resulted in cavity shrinkage from an open to closed conformation. This study confirms the conformational changes of catalytic triads involved in the catalytic reaction and presents a proposed mechanism for substrate reduction based on structural observations.

The effect of training to target cognitive biases towards social rejection in eating disorders.

OBJECTIVE: This study examined the effect of cognitive bias modification for interpretation (CBM-I) training in Korean women with eating disorders (EDs). METHOD: Sixty-three women with EDs participated in the study. Participants were randomly assigned to the intervention group where they received six sessions of CBM-I training (n = 31) in addition to treatment-as-usual or were put on a waiting list (n = 32). Participants' interpretation and attention biases, emotion regulation, affect, and ED psychopathology were assessed at baseline, end-of-intervention (4 weeks), and follow-up (8 weeks). RESULTS: Participants who completed the CBM-I training displayed greater reductions in negative interpretation bias (Δη2 = 0.107) and emotion dysregulation (Δη2 = 0.085) with medium to large effect sizes compared to the control group, which were maintained from baseline to follow-up. Disengagement from negative faces and a focus on positive faces was found in the intervention group with a moderate effect size at the end-of-intervention (Δη2 = 0.090). Both intervention and control groups showed improvements in ED psychopathology. Baseline neuroticism was positively correlated with CBM-I effect. DISCUSSION: The results suggest that modifying interpretation bias towards ambiguous social stimuli might be an effective adjuvant treatment to reduce negative expectations of social situations and improve emotion regulation in women with bulimia nervosa and anorexia nervosa.

Effect of modifying negative interpretation bias toward ambiguous social stimuli across eating and personality disorders.

OBJECTIVE: Heightened sensitivity toward social rejection has been implicated in eating disorders (ED) and personality disorder (PD). This study examined the effect of a cognitive bias modification training (CBM-I) targeting the interpretation of ambiguous social situations in individuals with comorbid ED and PD. METHOD: A total of 128 participants [33 with ED and PD, 22 with ED-only, 22 with PD-only, and 51 healthy controls (HC)] were recruited from a hospital and university settings, and included in the final analyses. The participants were randomly assigned to a CBM-I task with benign resolutions or a control task with neutral resolutions in a counterbalanced order in two sessions using a within-subject design. Interpretation bias toward social stimuli was measured using the ambiguous sentence completion task before and after completing the assigned task. RESULTS: The CBM-I task increased benign and decreased negative interpretations with large effect sizes in the diagnostic groups, and with a moderate effect size in the HC group. Participants' anxiety levels were also reduced after the task. The size of the change in negative interpretation was positively associated with baseline negative affect, and negatively associated with baseline positive affect. DISCUSSION: The results suggest that modifying interpretation bias has the potential as a transdiagnostic target of treatment for ED and PD, and a fully powered clinical trial with consecutive sessions would be warranted. PUBLIC SIGNIFICANCE: Participants with eating disorders and/or personality disorder, and healthy controls completed a single session of a cognitive training intervention targeting rejection sensitivity. The training produced a large decrease in negative interpretation in the diagnostic groups, and a moderate effect in healthy controls. The findings indicate that training for positive processing of social information may be of value to augment treatment in conditions such as eating disorders and personality disorder, in which there are high levels of rejection sensitivity.

Ceramic Femoral Heads Exhibit Lower Wear Rates Compared to Cobalt Chrome: A Meta-Analysis.

BACKGROUND: Wear between the femoral head and acetabular liners continues to limit the longevity of total hip arthroplasty implants despite advances in implant materials. The purpose of this meta-analysis was to compare linear wear rates of cobalt-chromium (CoCr) and fourth-generation ceramic femoral heads on highly cross-linked polyethylene (XLPE) liners. METHODS: A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted to identify all studies between 2003 and 2020 that examined in vivo wear rates of either fourth-generation ceramics or CoCr femoral heads on XLPE liners. Studies were analyzed in a weighted means analysis of wear rates and a random effects meta-analysis. RESULTS: A total of 36 studies met inclusion criteria (1,657 CoCr and 659 ceramic patients). The pooled, weighted mean wear rate was 0.063 mm/year (standard deviation [SD]: 0.061, confidence interval [CI]: 0.049-0.077) for CoCr and 0.047 mm/year (SD: 0.057, CI: 0.033-0.062; P < .01) for ceramic (P < .01). A meta-analysis of 4 studies directly comparing ceramic and CoCr found that CoCr heads demonstrated 0.029 mm/year more wear than ceramic heads (95% CI: 0.026-0.059, P = .306). Mean wear for 32-mm heads was significantly higher for ceramic (P < .01), while mean wear for 36-mm heads was significantly higher for CoCr (P < .01). CONCLUSION: Fourth-generation ceramic femoral heads were found to have significantly lower wear rates than CoCr heads. Unlike previous studies, this meta-analysis included only in vivo studies and those with the same generation of highly XLPE liners.

Vitamin D3 Supplementation Prior to Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: The purpose of this randomized controlled trial was to determine if a one-time dose of vitamin D3 prior to total knee arthroplasty improves function and patient-reported outcomes, while decreasing complications. METHODS: One hundred seven patients undergoing primary total knee arthroplasty were randomized to receive 50,000 international units vitamin D3 (57 patients) or placebo (50 patients) on the morning of surgery. Power analysis determined 45 patients were required in each cohort to detect a minimal clinically important difference of 6 points in the functional component of the 2011 version of the Knee Society Score (KSS), assuming an alpha of 0.05 and power of 80%. KSS and a Timed Up and Go Test (TUGT) were measured preoperatively and at 3 and 6 weeks postoperatively. RESULTS: There was no difference in improvement of KSS at 3 weeks (+4.8 points vitamin D3 versus +3.0 points placebo; P = .6) or 6 weeks (+14.5 points vitamin D3 versus +12.4 points placebo; P = .5) from baseline. There was no difference in change in TUGT at 3 weeks (+1.2 seconds vitamin D3 versus +0.6 seconds placebo; P = .6) or 6 weeks (-0.3 seconds vitamin D3 versus -0.9 seconds placebo; P = .6) from baseline. There were 4 complications in the placebo cohort within the first 90 days postoperatively and 5 complications in the vitamin D3 cohort (P = 1.0). CONCLUSION: Supplementation with 50,000 international units vitamin D3 on the day of surgery failed to demonstrate statistical significant differences in functional KSS, TUGT times, or complications in the early postoperative period compared to placebo. LEVEL OF EVIDENCE: Level I, therapeutic study.

Open-Air Testing of Dual-Comb Time-of-Flight Measurement.

We configured a long-distance ranging apparatus to test the principle of dual-comb time-of-flight measurement using ultrashort lasers. Emphasis was given to the evaluation of open-air performance quantitatively in terms of the measurement resolution and stability. The test results revealed that our dual-comb asynchronous optical pulse sampling permits micrometer-resolved ranging with a repeatability of 2.05 µm over a 648 m distance in dry weather conditions. Further atmospheric effects were evaluated in three different weather conditions with corresponding Allan deviations. Finally, the capability of simultaneous determination of multiple targets was verified with the potential of advanced industrial applications, such as manufacturing, surveying, metrology, and geodesy.

Can images crowdsourced from the internet be used to train generalizable joint dislocation deep learning algorithms?

OBJECTIVE: Deep learning has the potential to automatically triage orthopedic emergencies, such as joint dislocations. However, due to the rarity of these injuries, collecting large numbers of images to train algorithms may be infeasible for many centers. We evaluated if the Internet could be used as a source of images to train convolutional neural networks (CNNs) for joint dislocations that would generalize well to real-world clinical cases. METHODS: We collected datasets from online radiology repositories of 100 radiographs each (50 dislocated, 50 located) for four joints: native shoulder, elbow, hip, and total hip arthroplasty (THA). We trained a variety of CNN binary classifiers using both on-the-fly and static data augmentation to identify the various joint dislocations. The best-performing classifier for each joint was evaluated on an external test set of 100 corresponding radiographs (50 dislocations) from three hospitals. CNN performance was evaluated using area under the ROC curve (AUROC). To determine areas emphasized by the CNN for decision-making, class activation map (CAM) heatmaps were generated for test images. RESULTS: The best-performing CNNs for elbow, hip, shoulder, and THA dislocation achieved high AUROCs on both internal and external test sets (internal/external AUC): elbow (1.0/0.998), hip (0.993/0.880), shoulder (1.0/0.993), THA (1.0/0.950). Heatmaps demonstrated appropriate emphasis of joints for both located and dislocated joints. CONCLUSION: With modest numbers of images, radiographs from the Internet can be used to train clinically-generalizable CNNs for joint dislocations. Given the rarity of joint dislocations at many centers, online repositories may be a viable source for CNN-training data.

The Cost-Effectiveness of Tibial Metaphyseal Cones in Revision Total Knee Arthroplasty.

BACKGROUND: The purpose of this study is to evaluate the cost-effectiveness of tibial cones in revision total knee arthroplasty. METHODS: A Markov model was used for cost-effectiveness analysis. The average cone price was obtained from Orthopedic Network News. The average cone aseptic loosening rate was determined by literature review. Hospitalization costs and baseline re-revision rates were calculated using the PearlDiver Database. RESULTS: The maximum cost-effective cone price varied from $3514 at age 40 to $648 at age 90, compared to the current average selling price of $4201. Cones became cost-effective with baseline aseptic loosening rates of 0.89% annually at age 40 to 4.38% annually at age 90, compared to the current average baseline loosening rate of 0.76% annually. CONCLUSION: For the average patient, tibial cones are not cost-effective, but may become so at lower prices, in younger patients, or in patients at substantially increased risk of aseptic loosening.

Detecting total hip arthroplasty dislocations using deep learning: clinical and Internet validation.

OBJECTIVE: Periprosthetic dislocations of total hip arthroplasty (THA) are time-sensitive injuries, as the longer diagnosis and treatment are delayed, the more difficult they are to reduce. Automated triage of radiographs with dislocations could help reduce these delays. We trained convolutional neural networks (CNNs) for the detection of THA dislocations, and evaluated their generalizability by evaluating them on external datasets. METHODS: We used 357 THA radiographs from a single hospital (185 with dislocation [51.8%]) to develop and internally test a variety of CNNs to identify THA dislocation. We performed external testing of these CNNs on two datasets to evaluate generalizability. CNN performance was evaluated using area under the receiving operating characteristic curve (AUROC). Class activation mapping (CAM) was used to create heatmaps of test images for visualization of regions emphasized by the CNNs. RESULTS: Multiple CNNs achieved AUCs of 1 for both internal and external test sets, indicating good generalizability. Heatmaps showed that CNNs consistently emphasized the THA for both dislocated and located THAs. CONCLUSION: CNNs can be trained to recognize THA dislocation with high diagnostic performance, which supports their potential use for triage in the emergency department. Importantly, our CNNs generalized well to external data from two sources, further supporting their potential clinical utility.

Stabilization of hypoxia-inducible factor ameliorates glomerular injury sensitization after tubulointerstitial injury.

Previously, we found that mild tubulointerstitial injury sensitizes glomeruli to subsequent injury. Here, we evaluated whether stabilization of hypoxia-inducible factor-α (HIF-α), a key regulator of tissue response to hypoxia, ameliorates tubulointerstitial injury and impact on subsequent glomerular injury. Nep25 mice, which express the human CD25 receptor on podocytes under control of the nephrin promotor and develop glomerulosclerosis when a specific toxin is administered were used. Tubulointerstitial injury, evident by week two, was induced by folic acid, and mice were treated with an HIF stabilizer, dimethyloxalylglycine or vehicle from week three to six. Uninephrectomy at week six assessed tubulointerstitial fibrosis. Glomerular injury was induced by podocyte toxin at week seven, and mice were sacrificed ten days later. At week six tubular injury markers normalized but with patchy collagen I and interstitial fibrosis. Pimonidazole staining, a hypoxia marker, was increased by folic acid treatment compared to vehicle while dimethyloxalylglycine stimulated HIF-2α expression and attenuated tubulointerstitial hypoxia. The hematocrit was increased by dimethyloxalylglycine along with downstream effectors of HIF. Tubular epithelial cell injury, inflammation and interstitial fibrosis were improved after dimethyloxalylglycine, with further reduced mortality, interstitial fibrosis, and glomerulosclerosis induced by specific podocyte injury. Thus, our findings indicate that hypoxia contributes to tubular injury and consequent sensitization of glomeruli to injury. Hence, restoring HIFs may blunt this adverse crosstalk of tubules to glomeruli.

Calcium Intake and Iron Status in Human Studies: A Systematic Review and Dose-Response Meta-Analysis of Randomized Trials and Crossover Studies.

BACKGROUND: The interaction between dietary (and supplementary) divalent ions has been a long-standing issue in human nutrition research. Developing an optimal calcium and iron supplementation recommendation requires detailed knowledge of the potential trade-offs between: 1) the clinical effects of concurrent intake on iron absorption and hematological indices; and 2) the potentially negative effects of separated ingestion on adherence to iron and/or calcium supplements. Human clinical studies have examined the effects of calcium intake on iron status, but there are no meta-analyses or recent reviews summarizing the findings. OBJECTIVES: To synthesize peer-reviewed, human, randomized, and cross-over studies on effects of calcium consumption on iron indices without age, gender, or any other restrictions. METHODS: Weighted mean differences for total, heme, and nonheme iron absorption (%) and serum ferritin (µg/L) were obtained from pooled analysis of the highest daily calcium intake compared to the lowest daily calcium intake. RESULTS: The negative effect of calcium intake was statistically significant in short-term iron absorption studies, but the effect magnitude was low [weighted mean difference (WMD) = -5.57%; 95% CI: -7.09 to -4.04]. The effect of calcium on the iron status was mixed. The inverse dose-response association of calcium intake with the serum ferritin concentration was significant (P value = 0.0004). There was, however, no reduction in the hemoglobin concentration (WMD = 1.22g/L;  95% CI:  0.37-2.07). CONCLUSIONS: The existing body of studies is insufficient to make recommendations with high confidence due to heterogeneity in designs, limitations of ferritin as an iron biomarker, and a lack of intake studies in pregnant women. Prescribing separation of prenatal calcium and iron supplements in free-living individuals is unlikely to affect the anemia burden. There is a need for effectiveness trials comparing the effects of prescribing separated intake to concurrent intake, with functional endpoints as primary outcomes and adherence to each supplement as intermediate outcomes.

Preoperative Corticosteroid Injections Demonstrate a Temporal and Dose-Dependent Relationship with the Rate of Postoperative Infection Following Total Hip Arthroplasty.

BACKGROUND: Corticosteroid injections (CSI) are commonly used for the treatment of osteoarthritis of the hip. There is concern, however, that these injections may increase the risk of postoperative infection if a subsequent total hip arthroplasty (THA) is performed. The purpose of the present investigation is to determine the relationship between CSI and the risk of periprosthetic joint infection (PJI) and surgical site infections (SSIs) following THA. METHODS: The PearlDiver database was reviewed for patients undergoing THA from 2011 to 2018. Patients with unilateral hip osteoarthritis who received an intra-articular hip CSI prior to ipsilateral THA were matched in a sequential 1:1 fashion based on age, gender, and Charlson Comorbidity Index with THA patients who did not receive an injection in the preoperative period. PJI and SSI within 6 months of the surgical procedure were recorded. Statistical analysis included chi-squared test and multivariate logistic regression. Results were considered significant at P < .05. RESULTS: In total, 29,058 patients underwent a hip CSI within 6 months prior to THA. CSI within 4 months of surgery was associated with a higher incidence of PJI at 6-month follow up (1.6% vs 1.1%, P = .040). An injection within 1 month of surgery corresponded to a higher odds of PJI (odds ratio [OR] 1.97) than an injection 4 months prior to surgery (OR 1.24). Furthermore, the quantity of CSI administered within the 3 months prior to THA demonstrated a dose-dependent relationship, with each subsequent injection increasing odds of PJI (OR 1.45-3.59). A similar relationship was observed for SSI. CONCLUSION: There appears to be both a time and dose-dependent association of hip CSI and PJI following THA. Surgeons should consider delaying elective THA if a CSI has been administered within the 4 months prior to the planned procedure.

National Trends in Post-Acute Care Costs Following Total Knee Arthroplasty From 2007 to 2016.

BACKGROUND: Post-acute care continues to represent a target for cost savings with increasing popularity of value-based payment models in total knee arthroplasty (TKA). Rapid recovery and accelerated rehabilitation protocols have been successful in reducing costs at the institutional level, but national trends are less clear. This study aimed to determine if advancements in perioperative care led to a reduction in post-acute care costs and resource utilization following TKA. METHODS: We reviewed a consecutive series of 79,843 primary TKA patients from the Humana claims dataset from 2007 to 2016. Post-acute care costs included any claims within 90 days of surgery for subacute or inpatient rehabilitation, home health, outpatient or emergency visits, prescription medications, physical therapy, and readmissions. Demographics, episode-of-care and post-acute care costs, readmissions, and discharge disposition were compared. Controlling for demographics and comorbidities, multivariate regression analyses were performed to compare trends in discharge disposition and post-acute care costs. RESULTS: From 2007 to 2016, the average episode-of-care costs ($46,754 vs $31,856) and post-acute care costs per patient decreased ($20,224 vs $13,498). Rates of discharge to skilled nursing facilities (25.0% vs 22.5%) and inpatient rehabilitation also declined (12.4% vs 2.1%). Readmissions also decreased (8.1% vs 7.1%) saving an average of $324 per patient. When compared to 2007-2012, total costs declined most rapidly after 2013 primarily due to a $3516 (21%) decrease in post-acute spending. CONCLUSION: There has been a substantial decline in post-acute care costs and resource utilization following TKA, with the largest decrease occurring following the introduction of Medicare bundled payment models in 2013.

Revision Surgery for Instability After Total Hip Arthroplasty: Does Timing Matter?

BACKGROUND: Instability is a common reason for revision surgery after total hip arthroplasty (THA). Recent studies suggest that revisions performed in the early postoperative period are associated with higher complication rates. The purpose of this study is to assess the effect of timing of revision for instability on subsequent complication rates. METHODS: The Medicare Part A claims database was queried from 2010 to 2017 to identify revision THAs for instability. Patients were divided based on time between index and revision surgeries: <1, 1-2, 2-3, 3-6, 6-9, 9-12, and >12 months. Complication rates were compared between groups using multivariate analyses to adjust for demographics and comorbidities. RESULTS: Of 445,499 THAs identified, 9298 (2.1%) underwent revision for instability. Revision THA within 3 months had the highest rate of periprosthetic joint infection (PJI): 14.7% at <1 month, 12.7% at 1-2 months, and 10.6% at 2-3 months vs 6.9% at >12 months (P < .001). Adjusting for confounding factors, PJI risk remained elevated at earlier periods: <1 month (adjusted odds ratio [aOR]: 1.84, 95% confidence interval [CI]: 1.51-2.23, P < .001), 1-2 months (aOR: 1.45, 95% CI: 1.16-1.82, P = .001), 2-3 months (aOR: 1.35, 95% CI: 1.02-1.78, P = .036). However, revisions performed within 9 months of index surgery had lower rates of subsequent instability than revisions performed >12 months (aOR: 0.67-0.85, P < .050), which may be due to lower rates of acetabular revision and higher rates of head-liner exchange in this later group. CONCLUSION: When dislocation occurs in the early postoperative period, delaying revision surgery beyond 3 months from the index procedure may be warranted to reduce risk of PJI.

Understanding the difference between symptoms of focal cartilage defects and osteoarthritis of the knee: a matched cohort analysis.

PURPOSE: Comparing symptoms of patients with focal cartilage defects of the knee to those with knee osteoarthritis. METHODS: Prospectively maintained databases identified patients with focal cartilage defects (FCD group) who underwent osteochondral allograft transplantation and patients with osteoarthritis (OA group) undergoing arthroplasty. Patients between 18 and 55 years of age were included and matched based on age. Baseline patient demographics, symptoms, and patient-reported outcomes including the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR), SF-12, and VR-12 questionnaires were recorded. Patient symptoms and individual responses of the KOOS JR were compared between groups. Regression analysis was used to evaluate the association between pre-operative factors that significantly differed between groups and the KOOS JR questionnaire. RESULTS: Sixty-four patients were included: 32 patients in each group. The FCD group had a significantly lower body mass index (BMI) (p = 0.04) and greater number of workers' compensation cases (p = 0.027) when compared to the OA group. Patients in the OA group complained more frequently of medial-sided pain (p = 0.02) and knee swelling (p = 0.003). The OA cohort also had greater pain with fully straightening the knee (p = 0.012), pain with standing upright (p = 0.016), and pain with rising from sitting (p = 0.003). Patients in the FCD group had greater KOOS JR outcome scores (51.5 ± 12.9 vs. 41.5 ± 20.5; p = 0.023). CONCLUSION: When compared to patients with focal cartilage defects, adults with knee osteoarthritis scheduled for knee arthroplasty have a more severe presentation of symptoms, particularly medial-sided pain, swelling of the knee, pain associated with straightening the knee, standing upright, and rising from sitting.