Is a Rapid Recovery Protocol for THA and TKA Associated With Decreased 90-day Complications, Opioid Use, and Readmissions in a Health Safety-net Hospital?

BACKGROUND

Patients treated at a health safety-net hospital have increased medical complexity and social determinants of health that are associated with an increasing risk of complications after TKA and THA. Fast-track rapid recovery protocols (RRPs) are associated with reduced complications and length of stay in the general population; however, whether that is the case among patients who are socioeconomically disadvantaged in health safety-net hospitals remains poorly defined.

QUESTIONS/PURPOSES

When an RRP protocol is implemented in a health safety-net hospital after TKA and THA: (1) Was there an associated change in complications, specifically infection, symptomatic deep venous thromboembolism (DVT), symptomatic pulmonary embolism (PE), myocardial infarction (MI), and mortality? (2) Was there an associated difference in inpatient opioid consumption? (3) Was there an associated difference in length of stay and 90-day readmission rate? (4) Was there an associated difference in discharge disposition?

METHODS

An observational study with a historical control group was conducted in an urban, academic, tertiary-care health safety-net hospital. Between May 2022 and April 2023, an RRP consistent with current guidelines was implemented for patients undergoing TKA or THA for arthritis. We considered all patients aged 18 to 90 years presenting for primary TKA and THA as eligible. Based on these criteria, 562 patients with TKAs or THAs were eligible. Of these 33% (183) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 67% (379) for evaluation. Patients in the historical control group (September 2014 to May 2022) met the same criteria, and 2897 were eligible. Of these, 31% (904) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 69% (1993) for evaluation. The mean age in the historical control group was 61 ± 10 years and 63 ± 10 years in the RRP group. Both groups were 36% (725 of 1993 and 137 of 379) men. In the historical control group, 39% (770 of 1993) of patients were Black and 33% (658 of 1993) were White, compared with 38% (142 of 379) and 32% (121 of 379) in the RRP group, respectively. English was the most-spoken primary language, by 69% (1370 of 1993) and 68% (256 of 379) of the historical and RRP groups, respectively. A total of 65% (245 of 379) of patients in the RRP group had a peripheral nerve block compared with 54% (1070 of 1993) in the historical control group, and 39% (147 of 379) of them received spinal anesthesia, compared with 31% (615 of 1993) in the historical control group. The main elements of the RRP were standardization of preoperative visits, nutritional management, neuraxial anesthesia, accelerated physical therapy, and pain management. The primary outcomes were the proportions of patients with 90-day complications and opioid consumption. The secondary outcomes were length of stay, 90-day readmission, and discharge disposition. A multivariate analysis adjusting for age, BMI, gender, race, American Society of Anaesthesiologists class, and anesthesia type was performed by a staff biostatistician using R statistical programming.

RESULTS

After controlling for the confounding variables as noted, patients in the RRP group had fewer complications after TKA than those in the historical control group (odds ratio 2.0 [95% confidence interval 1.3 to 3.3]; p = 0.005), and there was a trend toward fewer complications in THA (OR 1.8 [95% CI 1.0 to 3.5]; p = 0.06), decreased opioid consumption during admission (517 versus 676 morphine milligram equivalents; p = 0.004), decreased 90-day readmission (TKA: OR 1.9 [95% CI 1.3 to 2.9]; p = 0.002; THA: OR 2.0 [95% CI 1.6 to 3.8]; p = 0.03), and increased proportions of discharge to home (TKA: OR 2.4 [95% CI 1.6 to 3.6]; p = 0.01; THA: OR 2.5 [95% CI 1.5 to 4.6]; p = 0.002). Patients in the RRP group had no difference in the mean length of stay (TKA: 3.2 ± 2.6 days versus 3.1 ± 2.0 days; p = 0.64; THA: 3.2 ± 2.6 days versus 2.8 ± 1.9 days; p = 0.33).

CONCLUSION

Surgeons should consider developing an RRP in health safety-net hospitals. Such protocols emphasize preparing patients for surgery and supporting them through the acute recovery phase. There are possible benefits of neuraxial and nonopioid perioperative anesthesia, with emphasis on early mobility, which should be further characterized in comparative studies. Continued analysis of opioid use trends after discharge would be a future area of interest. Analysis of RRPs with expanded inclusion criteria should be undertaken to better understand the role of these protocols in patients who undergo revision TKA and THA.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The Pregnant Arthroplasty Surgeon: A Women in Arthroplasty Committee Editorial

BACKGROUND

Women orthopaedic surgeons face unique challenges during their careers. There are extremely low numbers of women in the field, particularly in the specialty of adult reconstruction. Factors contributing to low numbers of women entering this subspecialty include increased perceived physical demand relative to other fields, occupational hazards during pregnancy such as exposure to radiation and polymethylmethacrylate bone cement, concerns for work-life balance, and limited number of women within the subspecialty. The following editorial provides a framework to understand and manage the potential occupational hazards to pregnant and lactating surgeons, parental leave, and postpartum return to work. We aim to dispel any unfounded myths and provide evidence-based education that may help overcome these barriers. In doing so, we hope to encourage more women to consider adult reconstruction as a potential career.

METHODS

Our primary method consisted of completing an extensive literature review on the past and current articles about the aforementioned barriers which may contribute to the low number of women entering adult reconstruction. After this literature search was completed, we composed a comprehensive editorial that provided evidence-based education and recommendations for medical professionals.

CONCLUSIONS

Issues pertaining to parenthood, pregnancy, and lactation pose barriers to success for women in orthopedic surgery. These concerns may dissuade talented women from pursuing a rewarding career in adult reconstruction. Education on these issues is needed to help our early-career colleagues plan and care for their families. Clearly stated and published policies should be made available in all training programs, fellowships, and clinical practices to allow understanding and unbiased implementation. By being more inclusive, adult reconstruction will have access to the best possible surgeons, which will benefit not only patients but the field as a whole.

Combined Single-Shot Infiltration Between the Popliteal Artery and Capsule of the Knee and Adductor Canal Block With Bupivacaine, Dexmedetomidine, and Dexamethasone for Total Knee Arthroplasty: A Propensity-Matched Analysis

Background

To investigate if combined single-shot adductor canal blockade (ACB) and infiltration between the popliteal artery and capsule of the knee (IPACK) provide better postoperative pain management compared to ACB alone for patients undergoing unilateral total knee arthroplasty (TKA).

Methods

This retrospective cohort study included adult patients who underwent primary, unilateral TKA. Patients were separated into 2 cohorts: single-shot ACB alone (performed with bupivacaine 0.25%) and combined single-shot ACB + IPACK (performed with bupivacaine 0.25%, dexmedetomidine 1 mg/kg, and dexamethasone 4 mg). Patients were propensity-matched 1:1. The primary study outcome was total opioid consumption converted to morphine milligram equivalents (MME) per eight-hour interval and postoperative day. Secondary outcomes included pain scores, length of stay, ambulation distance, return to emergency department, hospital readmission, and 30-day adverse events.

Results

One hundred eighty patients were identified, of which propensity matching used 71% to yield 64 patients receiving ACB alone and 64 receiving combined ACB + IPACK. Combined ACB + IPACK had significantly lower total summative MME throughout the entire postoperative stay (P = .002) and cumulatively after the first 24 hours (P < .001). Combined ACB + IPACK also had lower mean pain scores for 0-8 hours (P = .005) and 8-16 hours (P = .009) postoperatively. There were no significant differences in secondary outcomes.

Conclusions

Combined single-shot ACB + IPACK block was associated with lower total narcotic intake and mean pain scores during most of the immediate postoperative period following primary, unilateral TKA compared to ACB alone. Implementing longer-acting, single-shot ACB + IPACK for TKA can balance effective and more selective pain management with early rehabilitation.

Modular Knee Arthrodesis as Definitive Treatment for Periprosthetic Infection, Bone Loss, and Failure of the Extensor Mechanism After Total Knee Arthroplasty

Background

Periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) can result in bone and soft-tissue loss, leg length discrepancies, and dysfunctional extensor mechanisms. While above-knee amputation (AKA) is an established salvage treatment, modular knee arthrodesis (MKA) is a viable option that provides rigid stability and maintains leg length even in patients with severe bone and soft-tissue loss. We sought to report the outcomes of patients with an MKA as the definitive treatment.

Methods

We retrospectively reviewed 8 patients implanted with an MKA at 2 institutions between 2016 and 2022. The mean age was 69.63 years, and 50.0% of patients were women. All patients were indicated for conversion to an MKA as the definitive treatment in the setting of treated chronic PJI after TKA, severe bone loss, and failure of the extensor mechanism not amenable to repair. Medical records and radiographs were reviewed.

Results

No patients required incision and drainage or exchange of their MKA for PJI at mean 2-year follow-up. One patient required 2 revisions for mechanical failure of his implant at 5.0 and 6.4 years postoperatively.

Conclusions

MKA is a viable permanent alternative to AKA for patients with treated chronic PJI and dysfunctional extensor mechanism after TKA. The procedure restores leg lengths in the setting of severe bone and soft-tissue loss, therefore allowing patients to ambulate independently. Still, surgeons should be aware of the potential for mechanical failure requiring revision.

Mobile Application Use and Patient Engagement in Total Hip and Knee Arthroplasty

» Mobile applications (MAs) are widely available for use during the perioperative period and are associated with increased adherence to rehabilitation plans, increased satisfaction with care, and considerable cost savings when used appropriately.» MAs offer surgeons and health care stakeholders the ability to collect clinical data and quality metrics that are important to value-based reimbursement models and clinical research.» Patients are willing to use wearable technology to assist with data collection as part of MAs but prefer it to be comfortable, easy to apply, and discreet.» Smart implants have been developed as the next step in MA use and data collection, but concerns exist pertaining to patient privacy and cost.» The ongoing challenge of MA standardization, validation, equity, and cost has persisted as concerns regarding widespread use.

The Impact of the COVID-19 Pandemic on the Practice of Hip and Knee Arthroplasty

» The COVID-19 global pandemic resulted in unprecedented disruptions in care including massive surgical cancelations, a shift to outpatient surgery, and novel medical risks posed by COVID-19 infection on patients undergoing joint replacement surgery.» Refined patient optimization pathways have facilitated safe, efficient outpatient total joint arthroplasty in patient populations that may not otherwise have been considered eligible.» Rapid innovations emerged to deliver care while minimizing the risk of disease transmission which included the widespread adoption of telemedicine and virtual patient engagement platforms.» The widespread adoption of virtual technology was similarly expanded to resident education and continuing medical activities, which has improved our ability to propagate knowledge and increase access to educational initiatives.» Novel challenges borne of the pandemic include profound personnel shortages and supply chain disruptions that continue to plague efficiencies and quality of care in arthroplasty and require creative, sustainable solutions.

A Comparison of the Caprini Score With an Institutional Risk Assessment Tool for Prediction of Venous Thromboembolism After Total Joint Arthroplasty at an Urban Tertiary Care Health Safety Net Hospital

Background

Patients undergoing total joint arthroplasty (TJA) are at increased risk for venous thromboembolism (VTE). Prediction tools such as the Caprini Risk Assessment Model (RAM) have been developed to identify patients at higher risk. However, studies have reported heterogeneous results when assessing its efficacy for TJA. Patients treated in an urban health safety net hospital have increased medical complexity, advanced degenerative joint disease, and severe disability prior to TJA increasing the risk of VTE. We hypothesize that use of a tool designed to account for these conditions-the Boston Medical Center (BMC) VTE score-will more accurately predict VTE in this patient population.

Methods

A retrospective case-control study was performed including subjects 18 years of age and older who underwent primary or revision TJA in an urban academic health safety net hospital. Patients with hemiarthroplasties, simultaneous bilateral TJA, and TJA after acute trauma were excluded. A total of 80 subjects were included: 40 who developed VTE after TJA (VTE+) and 40 who did not develop VTE (controls). Subjects were matched by age, gender, and surgical procedure.

Results

There was a statistically significant difference between the mean BMC VTE score for VTE+ and controls (4.40 and 3.13, respectively, P = .036). Conversely, there was no statistical difference between the mean Caprini scores for VTE+ and controls (9.50 and 9.35, respectively, P = .797).

Conclusions

In a health safety-net patient population, an institutional RAM-the BMC VTE score-was found to be more predictive of VTE than the modified Caprini RAM following TJA. The BMC-VTE score should be externally validated to confirm its reliability in VTE prediction in similar patient populations.

Mobile Application's Effect on Patient Satisfaction and Compliance in Total Joint Arthroplasty: A Systematic Review and Meta-analysis

Use of mobile applications to improve patient engagement is particularly promising in total joint arthroplasty (TJA) whereby successful outcomes are predicated by patient engagement. In accordance with published guidelines by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, studies were searched, screened, and appraised for quality on various search engines. Hedges' g or odds ratios of patient adherence were reported. Twelve studies met the inclusion criteria, and the average age of 9,521 patients included was 60 years. Six studies concluded that mobile applications improved patients' satisfaction, with Hedges' g revealing an effect size of 1.64 (95% confidence interval [CI] 0.90 to 2.37), P < 0.001, in favor of mobile applications increasing patient satisfaction. Six studies reported improvements in compliance demonstrating an odds ratio for improved adherence of 4.57 (95% CI, 1.66 to 12.62), P < 0.001. Two studies reported a reduction in unscheduled office or emergency department visits. With evolving reimbursement policies linked to outcomes paired with the exponentially increasing volume of TJA performed, innovative ways to efficiently deliver high-quality care are in demand. Our systematic review is limited by a dearth of research on the nascent technology, but the available data suggest that mobile applications may enhance patient satisfaction, improve compliance, and reduce unscheduled visits after TJA.

Successful aging after elective surgery II: Study design and methods

BACKGROUND

The Successful Aging after Elective Surgery (SAGES) II study was designed to increase knowledge of the pathophysiology and linkages between delirium and dementia. We examine novel biomarkers potentially associated with delirium, including inflammation, Alzheimer's disease (AD) pathology and neurodegeneration, neuroimaging markers, and neurophysiologic markers. The goal of this paper is to describe the study design and methods for the SAGES II study.

METHODS

The SAGES II study is a 5-year prospective observational study of 400-420 community dwelling persons, aged 65 years and older, assessed prior to scheduled surgery and followed daily throughout hospitalization to observe for development of delirium and other clinical outcomes. Delirium is measured with the Confusion Assessment Method (CAM), long form, after cognitive testing. Cognitive function is measured with a detailed neuropsychologic test battery, summarized as a weighted composite, the General Cognitive Performance (GCP) score. Other key measures include magnetic resonance imaging (MRI), transcranial magnetic stimulation (TMS)/electroencephalography (EEG), and Amyloid positron emission tomography (PET) imaging. We describe the eligibility criteria, enrollment flow, timing of assessments, and variables collected at baseline and during repeated assessments at 1, 2, 6, 12, and 18 months.

RESULTS

This study describes the hospital and surgery-related variables, delirium, long-term cognitive decline, clinical outcomes, and novel biomarkers. In inter-rater reliability assessments, the CAM ratings (weighted kappa = 0.91, 95% confidence interval, CI = 0.74-1.0) in 50 paired assessments and GCP ratings (weighted kappa = 0.99, 95% CI 0.94-1.0) in 25 paired assessments. We describe procedures for data quality assurance and Covid-19 adaptations.

CONCLUSIONS

This complex study presents an innovative effort to advance our understanding of the inter-relationship between delirium and dementia via novel biomarkers, collected in the context of major surgery in older adults. Strengths include the integration of MRI, TMS/EEG, PET modalities, and high-quality longitudinal data.

Patterns and Persistence of Perioperative Plasma and Cerebrospinal Fluid Neuroinflammatory Protein Biomarkers After Elective Orthopedic Surgery Using SOMAscan

BACKGROUND

The neuroinflammatory response to surgery can be characterized by peripheral acute plasma protein changes in blood, but corresponding, persisting alterations in cerebrospinal fluid (CSF) proteins remain mostly unknown. Using the SOMAscan assay, we define acute and longer-term proteome changes associated with surgery in plasma and CSF. We hypothesized that biological pathways identified by these proteins would be in the categories of neuroinflammation and neuronal function and define neuroinflammatory proteome changes associated with surgery in older patients.

METHODS

SOMAscan analyzed 1305 proteins in blood plasma (n = 14) and CSF (n = 15) samples from older patients enrolled in the Role of Inflammation after Surgery for Elders (RISE) study undergoing elective hip and knee replacement surgery with spinal anesthesia. Systems biology analysis identified biological pathways enriched among the surgery-associated differentially expressed proteins in plasma and CSF.

RESULTS

Comparison of postoperative day 1 (POD1) to preoperative (PREOP) plasma protein levels identified 343 proteins with postsurgical changes ( P < .05; absolute value of the fold change [|FC|] > 1.2). Comparing postoperative 1-month (PO1MO) plasma and CSF with PREOP identified 67 proteins in plasma and 79 proteins in CSF with altered levels ( P < .05; |FC| > 1.2). In plasma, 21 proteins, primarily linked to immune response and inflammation, were similarly changed at POD1 and PO1MO. Comparison of plasma to CSF at PO1MO identified 8 shared proteins. Comparison of plasma at POD1 to CSF at PO1MO identified a larger number, 15 proteins in common, most of which are regulated by interleukin-6 (IL-6) or transforming growth factor beta-1 (TGFB1) and linked to the inflammatory response. Of the 79 CSF PO1MO-specific proteins, many are involved in neuronal function and neuroinflammation.

CONCLUSIONS

SOMAscan can characterize both short- and long-term surgery-induced protein alterations in plasma and CSF. Acute plasma protein changes at POD1 parallel changes in PO1MO CSF and suggest 15 potential biomarkers for longer-term neuroinflammation that warrant further investigation.

No Difference Between Hemiarthroplasty and Total Hip Arthroplasty in the Treatment of Pathologic Femoral Neck Fractures

BACKGROUND

Hemiarthroplasty (HA) and total hip arthroplasty (THA) have been widely discussed as treatment options for displaced osteoporotic femoral neck fractures. Pathologic femoral neck fractures from primary or metastatic tumors are comparatively rare and poorly investigated. The purpose of this study was to compare outcomes, complications, and perioperative survival for HA and THA in the treatment of pathologic femoral neck fractures of neoplastic etiology.

METHODS

A multicenter retrospective cohort study identified patients with pathologic femoral neck fractures treated with HA or THA from 2005 to 2018. Demographics, American Society of Anesthesiologists classification, Charlson comorbidity index, Dorr classification, histopathologic diagnosis, and surgical data were compared. The primary outcome was reoperation. Secondary outcomes included 90-day mortality, estimated blood loss, length of stay, periprosthetic fracture, periprosthetic joint infection, and Eastern Cooperative Oncology Group performance status.

RESULTS

There were 116 patients with HA and 48 patients with THA, with no differences between groups with regard to American Society of Anesthesiologists classification, Charlson comorbidity index, or Dorr classification. There were no differences between HA and THA in the primary outcome of reoperation (5.2% vs 4.2%, P = 1.00) or secondary outcomes of perioperative 90-day overall mortality (30.2% vs 25.0%, P = .51), estimated blood loss, transfusion rates, length of stay, discharge location, periprosthetic joint infection, periprosthetic fracture, or preoperative or postoperative Eastern Cooperative Oncology Group performance status.

CONCLUSIONS

Both HA and THA are viable options for the treatment of patients with pathologic femoral neck fractures and demonstrated no differences in reoperations, complications, perioperative 90-day mortality, or functional outcome scores.

LEVEL OF EVIDENCE

Level III.

The Role of Acupuncture in Postoperative Pain Management of Patients Undergoing Knee Arthroplasty Surgery: A Systematic Review and Meta-Analysis

»

Acupuncture after total knee arthroplasty (TKA) may decrease the incidence of postoperative nausea and vomiting (PONV).

»

Acupuncture did not decrease visual analog scale (VAS) scores in the 0 to 48-hour interval but did decrease VAS scores at >48 hours after TKA.

»

The heterogeneity of the studies prevented meta-analysis of opioid use with acupuncture after TKA; a systematic review demonstrated mixed results.

»

Additional studies are needed to investigate opioid reduction with acupuncture after TKA.

Development and internal validation of a predictive model of cognitive decline 36 months following elective surgery

INTRODUCTION

Our goal was to determine if features of surgical patients, easily obtained from the medical chart or brief interview, could be used to predict those likely to experience more rapid cognitive decline following surgery.

METHODS

We analyzed data from an observational study of 560 older adults (≥70 years) without dementia undergoing major elective non-cardiac surgery. Cognitive decline was measured using change in a global composite over 2 to 36 months following surgery. Predictive features were identified as variables readily obtained from chart review or a brief patient assessment. We developed predictive models for cognitive decline (slope) and predicting dichotomized cognitive decline at a clinically determined cut.

RESULTS

In a hold-out testing set, the regularized regression predictive model achieved a root mean squared error (RMSE) of 0.146 and a model r-square (R2 ) of .31. Prediction of "rapid" decliners as a group achieved an area under the curve (AUC) of .75.

CONCLUSION

Some of our models could predict persons with increased risk for accelerated cognitive decline with greater accuracy than relying upon chance, and this result might be useful for stratification of surgical patients for inclusion in future clinical trials.

One-Year Medicare Costs Associated With Delirium in Older Patients Undergoing Major Elective Surgery

Importance

Delirium is a common, serious, and potentially preventable problem for older adults, associated with adverse outcomes. Coupled with its preventable nature, these adverse sequelae make delirium a significant public health concern; understanding its economic costs is important for policy makers and health care leaders to prioritize care.

Objective

To evaluate current 1-year health care costs attributable to postoperative delirium in older patients undergoing elective surgery.

Design, Setting, and Participants

This prospective cohort study included 497 patients from the Successful Aging after Elective Surgery (SAGES) study, an ongoing cohort study of older adults undergoing major elective surgery. Patients were enrolled from June 18, 2010, to August 8, 2013. Eligible patients were 70 years or older, English-speaking, able to communicate verbally, and scheduled to undergo major surgery at 1 of 2 Harvard-affiliated hospitals with an anticipated length of stay of at least 3 days. Eligible surgical procedures included total hip or knee replacement; lumbar, cervical, or sacral laminectomy; lower extremity arterial bypass surgery; open abdominal aortic aneurysm repair; and open or laparoscopic colectomy. Data were analyzed from October 15, 2019, to September 15, 2020.

Exposures

Major elective surgery and hospitalization.

Main Outcomes and Measures

Cumulative and period-specific costs (index hospitalization, 30-day, 90-day, and 1-year follow-up) were examined using Medicare claims and extensive clinical data. Total inflation-adjusted health care costs were determined using data from Medicare administrative claims files for the 2010 to 2014 period. Delirium was rated using the Confusion Assessment Method. We also examined whether increasing delirium severity was associated with higher cumulative and period-specific costs. Delirium severity was measured with the Confusion Assessment Method-Severity long form. Regression models were used to determine costs associated with delirium after adjusting for patient demographic and clinical characteristics.

Results

Of the 566 patients who were eligible for the study, a total of 497 patients (mean [SD] age, 76.8 [5.1] years; 281 women [57%]; 461 White participants [93%]) were enrolled after exclusion criteria were applied. During the index hospitalization, 122 patients (25%) developed postoperative delirium, whereas 375 (75%) did not. Patients with delirium had significantly higher unadjusted health care costs than patients without delirium (mean [SD] cost, $146 358 [$140 469] vs $94 609 [$80 648]). After adjusting for relevant confounders, the cumulative health care costs attributable to delirium were $44 291 (95% CI, $34 554-$56 673) per patient per year, with the majority of costs coming from the first 90 days: index hospitalization ($20 327), subsequent rehospitalizations ($27 797), and postacute rehabilitation stays ($2803). Health care costs increased directly and significantly with level of delirium severity (none-mild, $83 534; moderate, $99 756; severe, $140 008), suggesting an exposure-response relationship. The adjusted mean cumulative costs attributable to severe delirium were $56 474 (95% CI, $40 927-$77 440) per patient per year. Extrapolating nationally, the health care costs attributable to postoperative delirium were estimated at $32.9 billion (95% CI, $25.7 billion-$42.2 billion) per year.

Conclusions and Relevance

These findings suggest that the economic outcomes of delirium and severe delirium after elective surgery are substantial, rivaling costs associated with cardiovascular disease and diabetes. These results highlight the need for policy imperatives to address delirium as a large-scale public health issue.

Machine Learning to Develop and Internally Validate a Predictive Model for Post-operative Delirium in a Prospective, Observational Clinical Cohort Study of Older Surgical Patients

BACKGROUND

Our objective was to assess the performance of machine learning methods to predict post-operative delirium using a prospective clinical cohort.

METHODS

We analyzed data from an observational cohort study of 560 older adults (≥ 70 years) without dementia undergoing major elective non-cardiac surgery. Post-operative delirium was determined by the Confusion Assessment Method supplemented by a medical chart review (N = 134, 24%). Five machine learning algorithms and a standard stepwise logistic regression model were developed in a training sample (80% of participants) and evaluated in the remaining hold-out testing sample. We evaluated three overlapping feature sets, restricted to variables that are readily available or minimally burdensome to collect in clinical settings, including interview and medical record data. A large feature set included 71 potential predictors. A smaller set of 18 features was selected by an expert panel using a consensus process, and this smaller feature set was considered with and without a measure of pre-operative mental status.

RESULTS

The area under the receiver operating characteristic curve (AUC) was higher in the large feature set conditions (range of AUC, 0.62-0.71 across algorithms) versus the selected feature set conditions (AUC range, 0.53-0.57). The restricted feature set with mental status had intermediate AUC values (range, 0.53-0.68). In the full feature set condition, algorithms such as gradient boosting, cross-validated logistic regression, and neural network (AUC = 0.71, 95% CI 0.58-0.83) were comparable with a model developed using traditional stepwise logistic regression (AUC = 0.69, 95% CI 0.57-0.82). Calibration for all models and feature sets was poor.

CONCLUSIONS

We developed machine learning prediction models for post-operative delirium that performed better than chance and are comparable with traditional stepwise logistic regression. Delirium proved to be a phenotype that was difficult to predict with appreciable accuracy.

Survivorship of Megaprostheses in Revision Hip and Knee Arthroplasty for Septic and Aseptic Indications: A Retrospective, Multicenter Study With Minimum 2-Year Follow-Up

Background

The use of megaprostheses in nononcologic patients has been associated with complication rates greater than 50%. In patients with prior periprosthetic joint infection (PJI) with subsequent two-stage reimplantation, this complication rate may be even higher. This study was to investigate the outcomes of megaprostheses in nononcologic patients undergoing revision hip/knee arthroplasty.

Methods

We retrospectively studied patients who underwent megaprosthesis replacements from 1999 to 2017 at 5 hospitals with minimum 24 months of follow-up. Patients were stratified based on history of prior PJI (septic vs aseptic) and location of the megaprosthesis (the hip or knee). Postoperative complications were classified as soft-tissue failure, aseptic loosening, structural failure, and infection.

Results

Of the 42 patients, 19 were in the septic cohort and 23 were in the aseptic cohort. The overall complication rate was 28.6%. Complication rates for the septic and aseptic cohorts were 32% and 26%, respectively (P = .74). By anatomic location, there were 2 of 13 (15%) and 10 of 29 (34%) complications in the hip and knee groups, respectively (P = .28). In the septic cohort, there were no (0%) complications in the hip group and 6 of 14 (43%) complications in the knee group (P = .13), all due to infection. In the aseptic cohort, there were 2 of 8 (25%) and 4 of 15 (27%) complications in the hip and knee groups, respectively (P = 1.0).

Conclusions

There is no difference in the postoperative complication rates between the septic or aseptic cohorts undergoing revision hip or knee megaprosthesis replacements. In patients with prior PJI, proximal femoral replacements have improved short-term survivorship compared with distal femoral or proximal tibial replacements.

Bone microarchitecture, biomechanical properties, and advanced glycation end-products in the proximal femur of adults with type 2 diabetes

Skeletal fragility is a major complication of type 2 diabetes mellitus (T2D), but there is a poor understanding of mechanisms underlying T2D skeletal fragility. The increased fracture risk has been suggested to result from deteriorated bone microarchitecture or poor bone quality due to accumulation of advanced glycation end-products (AGEs). We conducted a clinical study to determine whether: 1) bone microarchitecture, AGEs, and bone biomechanical properties are altered in T2D bone, 2) bone AGEs are related to bone biomechanical properties, and 3) serum AGE levels reflect those in bone. To do so, we collected serum and proximal femur specimens from T2D (n = 20) and non-diabetic (n = 33) subjects undergoing total hip replacement surgery. A section from the femoral neck was imaged by microcomputed tomography (microCT), tested by cyclic reference point indentation, and quantified for AGE content. A trabecular core taken from the femoral head was imaged by microCT and subjected to uniaxial unconfined compression tests. T2D subjects had greater HbA₁c (+23%, p ≤ 0.0001), but no difference in cortical tissue mineral density, cortical porosity, or trabecular microarchitecture compared to non-diabetics. Cyclic reference point indentation revealed that creep indentation distance (+18%, p ≤ 0.05) and indentation distance increase (+20%, p ≤ 0.05) were greater in cortical bone from T2D than in non-diabetics, but no other indentation variables differed. Trabecular bone mechanical properties were similar in both groups, except for yield stress, which tended to be lower in T2D than in non-diabetics. Neither serum pentosidine nor serum total AGEs were different between groups. Cortical, but not trabecular, bone AGEs tended to be higher in T2D subjects (21%, p = 0.09). Serum AGEs and pentosidine were positively correlated with cortical and trabecular bone AGEs. Our study presents new data on biomechanical properties and AGEs in adults with T2D, which are needed to better understand mechanisms contributing to diabetic skeletal fragility.

Magnetic Resonance Diffusion W Imaging in Cerebral Fat Embolism

The use of diffusion weighted imaging with apparent diffusion coefficient mapping in the diagnosis of cerebral fat embolism is shown here to demonstrate infarcts secondary to fat emboli more intensely than T2 weighted sequences 24 hours after the onset of symptoms. Embolic foci are hypointense on apparent diffusion coefficient mapping consistent with cytotoxic edema associated with cell death and restricted water diffusion. This technique increases the sensitivity for detecting cerebral fat embolism and offers a potentially important tool in its diagnosis.

First Report of 'Candidatus Phytoplasma solani' Strains Associated with Grapevine Bois Noir in Jordan

During a survey carried out in Jordanian vineyards in August and October 2012, grapevine (Vitis vinifera L.) plants showing typical grapevine yellows (GY) disease symptoms, including leaf discoloration and curling, berry shriveling, and irregular maturation of wood, were observed. In the same vineyards, bindweed (Convolvulus arvensis L.) plants showing stunting and leaf chromatic alteration were found, suggesting the involvement of phytoplasmas in the disease etiology. Using a CTAB method, total DNA was extracted from leaf veins of 25 symptomatic and two asymptomatic grapevines, and from five symptomatic and two asymptomatic bindweeds for PCR analysis. DNAs from periwinkle (Catharanthus roseus (L.) G. Don) plants infected by 'Ca. Phytoplasma asteris' strain SAY (group 16SrI), 'Ca. Phytoplasma solani' strain STOL (group 16SrXII), and 'Ca. Phytoplasma ulmi' strain EY1 (group 16SrV), were used as positive controls. DNAs from healthy periwinkle and reactions without template DNA were employed as negative controls. 16S rDNA nested PCRs, carried out using the primer pairs P1/P7, followed by R16F2n/R16R2 (1), yielded an amplicon of the expected size (1,250-bp) in three grapevine and in five bindweed samples, and in positive controls. Amplicons were not produced with DNA from 22 symptomatic grapevines (probably because samples were collected late in the growing season and phytoplasma distribution in plants was non-uniform [2]); nor from asymptomatic plants and negative controls. PCR products were sequenced by commercial services in Italy (Primm, Milan) and Korea (Macrogen Inc., Soul). Representative 16S rDNA nucleotide sequences were deposited in NCBI GenBank with accessions KC835139 (from grapevine) and KC835140 (from bindweed). The 16S rDNA nucleotide sequences of phytoplasmas identified in grapevine and bindweed in Jordan shared >99.5% sequence identity with 'Ca. Phytoplasma solani' reference strain STOL (AF248959), and carried identical STOL-unique signature sequences and distinguishing sequence blocks (3). Phylogenetic and in silico RFLP analyses confirmed the affiliation of phytoplasma strains identified in grapevine and bindweed in Jordan to the species 'Ca. Phytoplasma solani' (subgroup 16SrXII-A), opening an avenue to future studies on the dissemination and impact of Bois noir (BN) in Jordan. These studies may add new information about BN, previously reported in neighboring countries (4). Further studies will investigate the role of Hyalesthes obsoletus Signoret, a polyphagous Cixiidae responsible for the BN phytoplasma transmission in Europe, and other possible insect vector(s) in the BN spread in Jordan. References: (1) I.-M. Lee et al. Int. J. Syst. Bact. 48:1153, 1998. (2) F. E. Constable et al. Plant Pathol. 52:267, 2003. (3) F. Quaglino et al. Int. J. Syst. Evol. Microb. 63:2879. (4) E. Choueiri et al. Plant Dis. 86:697, 2002.

Allograft-prosthesis composite reconstruction of the proximal part of the humerus: surgical technique

BACKGROUND

Limb salvage following resection of a tumor in the proximal part of the humerus poses many challenges. Reconstructive options are limited because of the loss of periarticular soft-tissue stabilizers of the glenohumeral joint in addition to the loss of bone and articular cartilage. The purpose of this study was to evaluate the functional outcome and survival of the reconstruction following use of a humeral allograft-prosthesis composite for limb salvage.

METHODS

An allograft-prosthesis composite was used to reconstruct a proximal humeral defect following tumor resection in thirty-six consecutive patients at one institution over a sixteen-year period. The reconstruction was performed at the time of a primary tumor resection in thirty cases, after a failure of a reconstruction following a previous tumor resection in five patients, and following excision of a local recurrence in one patient. The mean duration of follow-up of the living patients was five years. Glenohumeral stability, function, implant survival, fracture rate, and union rate following the reconstructions were measured. Functional outcome and implant survival were analyzed on the basis of the amount of deltoid resection, whether the glenohumeral resection had been extra-articular or intra-articular, and the length of the humerus that had been resected.

RESULTS

One patient sustained a glenohumeral dislocation. Deltoid resection (partial or complete) resulted in a reduced postoperative range of motion in flexion and abduction but had no effect on the mean Musculoskeletal Tumor Society score. Extra-articular resections were associated with lower Musculoskeletal Tumor Society scores. All patients had either mild or no pain and normal hand function at the time of final follow-up. The overall estimated rate of survival of the construct, with revision as the end point, was 88% at ten years. There were three failures due to progressive prosthetic loosening that necessitated removal of the construct. Four patients required an additional bone-grafting procedure to treat a delayed union of the osteosynthesis site.

CONCLUSIONS

An allograft-prosthesis composite used for limb salvage following tumor resection in the proximal part of the humerus is a durable construct associated with an acceptable complication rate. Deltoid preservation and intra-articular resection are associated with a greater range of shoulder motion and a superior functional outcome, respectively.

Correlation between clinical outcome and growth factor pathway expression in osteogenic sarcoma

BACKGROUND

Multiple cell-signaling ligands and receptors-including vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), endothelial growth factor (EGF), v-akt murine thymoma viral oncogene homolog (AKT), platelet-derived growth factor (PDGF), mitogen-activated protein kinase (MAPK), and 70-kilodalton (kD) protein S6 kinase (p70S6 kinase)-reportedly are variably expressed in osteogenic sarcoma. Expression of these proteins may have future implications for prognostication and targeted therapy. The objective of the current study was to determine the relation between clinical outcome and the expression of these proteins.

METHODS

A paraffin-embedded microarray of 48 human osteogenic sarcoma tissue specimens was stained with the antibodies against VEGF, IGF, EGF, AKT, PDGF, MAPK, and p70S6 kinase. Staining for each protein included the total protein and, when applicable, the phosphorylated version of the protein. Immunohistochemical staining was then correlated with patient survival (overall survival [OS] and event-free survival [EFS]), histologic response to chemotherapy, and serum markers.

RESULTS

There was a negative correlation between VEGF receptor 3 (VEGF-R3) and both OS and EFS. VEGF-B was correlated with a poor histologic response to chemotherapy. Serum markers were not correlated with any specific proteins. When using a P value of .05, multiple correlations were observed between proteins of various pathways.

CONCLUSIONS

The current results suggested that the VEGF pathway is a critical signaling pathway in osteogenic sarcoma. These data have identified specific proteins within these pathways toward which future investigations should be directed to further clarify their prognostic potential.

Allograft-prosthesis composite reconstruction of the proximal part of the humerus: functional outcome and survivorship

BACKGROUND

Limb salvage following resection of a tumor in the proximal part of the humerus poses many challenges. Reconstructive options are limited because of the loss of periarticular soft-tissue stabilizers of the glenohumeral joint in addition to the loss of bone and articular cartilage. The purpose of this study was to evaluate the functional outcome and survival of the reconstruction following use of a humeral allograft-prosthesis composite for limb salvage.

METHODS

An allograft-prosthesis composite was used to reconstruct a proximal humeral defect following tumor resection in thirty-six consecutive patients at one institution over a sixteen-year period. The reconstruction was performed at the time of a primary tumor resection in thirty cases, after a failure of a reconstruction following a previous tumor resection in five patients, and following excision of a local recurrence in one patient. The mean duration of follow-up of the living patients was five years. Glenohumeral stability, function, implant survival, fracture rate, and union rate following the reconstructions were measured. Functional outcome and implant survival were analyzed on the basis of the amount of deltoid resection, whether the glenohumeral resection had been extra-articular or intra-articular, and the length of the humerus that had been resected.

RESULTS

One patient sustained a glenohumeral dislocation. Deltoid resection (partial or complete) resulted in a reduced postoperative range of motion in flexion and abduction but had no effect on the mean Musculoskeletal Tumor Society score. Extra-articular resections were associated with lower Musculoskeletal Tumor Society scores. All patients had either mild or no pain and normal hand function at the time of final follow-up. The overall estimated rate of survival of the construct, with revision as the end point, was 88% at ten years. There were three failures due to progressive prosthetic loosening that necessitated removal of the construct. Four patients required an additional bone-grafting procedure to treat a delayed union of the osteosynthesis site.

CONCLUSIONS

An allograft-prosthesis composite used for limb salvage following tumor resection in the proximal part of the humerus is a durable construct associated with an acceptable complication rate. Deltoid preservation and intra-articular resection are associated with a greater range of shoulder motion and a superior functional outcome, respectively.

Telescope allograft method to reconstitute the diaphysis in limb salvage surgery

We propose a surgical technique for structural allograft reconstitution of the diaphysis of long bones, maximizing surface contact between host and allograft bone. This method, analogous to a telescope, overlaps the graft and host bone, theoretically increasing bone surface contact substantially. We report the outcome of 22 telescoped allograft junction sites in 19 patients who lacked sufficient host bone to accommodate a regular-length stemmed implant. This joint-sparing reconstruction preserved 15 of 16 adjacent joints at risk for replacement. Five patients needed additional surgery, but none for nonunion. The diaphyseal length could be reconstructed enough so that a short prosthesis (less than the critical 40% of total bone length) could be used. This biologic method to reconstruct major segments of the diaphysis is best suited for patients with quantitatively or qualitatively deficient residual bone stock after tumor resection or prosthetic revision. We believe it is an excellent technique for revision knee megaprostheses when there is a short remnant of proximal femur.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Component alignment in revision total knee arthroplasty using diaphyseal engaging modular offset press-fit stems

We performed a retrospective study of the radiographic position of femoral and tibial components in a series of revision total knee arthroplasties using diaphyseal-engaging, press fit, modular stems. Fifty-two consecutive revision cases were performed. Femoral and tibial component alignment was measured preoperatively and postoperatively. The canal-filling ratio was measured and correlated with anatomic alignment. There was a trend toward improved alignment with increasing canal fill, suggesting that uncemented diaphyseal engaging press-fit modular stems facilitate accurate alignment for both femoral and tibial components in revision surgery.

Wound problems in total knee arthroplasty

Wound problems can often be prevented with careful planning. When transverse incisions are used for knee surgery many years prior to any anticipated knee arthroplasty, no major problems are typically encountered with a conventional, anterior longitudinal incision. We recommend lateral incisions (eg, after a previous lateral tibial plateau fracture) be reused for TKA. When confronted with multiple previous incisions, surgeons would best use the most recently healed or the most lateral. We prefer soft tissue reconstruction with expanders or a gastrocnemius flap if there are multiple incisions, if the skin and scar tissue are adherent to underlying tissue, or if wound healing seems questionable. Deep infection must be determined by aspiration. When present, we believe treatment must include irrigation, débridement, polyethylene exchange if acute, and resection arthroplasty if chronic. Poor wound healing is a potentially devastating complication that may result in multiple reconstructive procedures and even amputation. Early recognition followed by expeditious débridement and soft tissue reconstruction should be used for managing wound complications after TKA.

The unstable total knee arthroplasty: causes and cures

Surgery for the unstable total knee arthroplasty requires a deep understanding of the causes and a plan that specifically addresses them. Isolated ligament reconstructions and polyethylene insert exchanges generally do not work. Patients may experience "buckling" from pain, flexion contracture, recurvatum, or patellar problems. True mechanical instability may result from loosening, bone loss, prosthetic breakage, component size or position, fracture, wear, or collateral ligament failure. Only the last one typically requires a constrained implant. The possible modes (directions) of instability are the following: varus-valgus, recurvatum, flexion, and global. Revision surgery must eliminate deforming forces, most frequently frontal plane alignment. Prosthetic implants, no matter how well engineered, are not a substitute for diagnosis and surgical technique.