Daniel Cunningham

Specific Infectious Organisms Associated With Poor Outcomes in Treatment for Hip Periprosthetic Infection

BACKGROUND Periprosthetic hip infection treatment remains a significant challenge for orthopedics. Some studies have suggested that methicillin resistance and gram-negative organism type are associated with increased treatment failure. The aim of this research is to determine if specific organisms were associated with poor outcomes in treatment for hip periprosthetic infection. METHODS Records were reviewed of all patients between 2005 and 2015 who underwent treatment for infected partial or total hip arthroplasty. Characteristics of each patients treatment course were determined including baseline characteristics, infecting organism(s), infection status at final follow-up, surgeries for infection, and time in hospital. Baseline characteristics and organisms that were associated with clinical outcomes in univariate analysis were incorporated into multivariable outcomes models. RESULTS When compared with patients infected with other organism(s), patients infected with the following organisms had significantly decreased infection-free rates: Pseudomonas, methicillin-resistant Staphylococcus aureus (MRSA), and Proteus. Infection with certain organisms was associated with 1.13-2.58 additional surgeries: methicillin-sensitive S aureus, coagulase-negative Staphylococcus, MRSA, Pseudomonas, Peptostreptococcus, Klebsiella, Candida, diphtheroids, Propionibacterium acnes, and Proteus species. Specific organisms were associated with 8.56-24.54 additional days in hospital for infection: methicillin-sensitive S aureus, coagulase-negative Staphylococcus, Proteus, MRSA, Enterococcus, Pseudomonas, Klebsiella, beta-hemolytic Streptococcus, and diphtheroids. Higher comorbidity score was also associated with greater length of hospitalization. CONCLUSION MRSA, Pseudomonas, and Proteus were associated with all 3 outcomes of lower infection-free rate, more surgery, and more time in hospital in treatment for hip periprosthetic infection. Organism-specific outcome information may help individualize patient-physician discussions about the expected course of treatment for hip periprosthetic infection.

Common Medical Comorbidities Correlated With Poor Outcomes in Hip Periprosthetic Infection

BACKGROUND Periprosthetic infection has been linked to risk factors such as diabetes, obesity, and smoking among others. This study examined the relationship between common patient comorbidities and hip periprosthetic infection outcomes. METHODS We retrospectively reviewed the records of 149 culture-positive periprosthetic hip infections at our tertiary care center that underwent treatment between 2005 and 2015. Baseline characteristics and common comorbidities were analyzed with relation to rates of successfully treated infection, total surgeries for infection, and cumulative length of hospitalization using multivariate analysis. RESULTS Patients with coronary artery disease or anemia had significantly lower rate of successfully treated infection. Patients with anemia or chronic pulmonary disease underwent significantly more surgery, and patients with chronic pulmonary disease, psychiatric disease, anemia, or diabetes spent significantly longer time in hospital. CONCLUSION Potentially modifiable cardiovascular, respiratory, and psychiatric diseases were associated with a decreased rate of successfully treated infection, more surgery, and longer hospitalization in treatment for hip periprosthetic infection in multivariate analysis.

Advanced Imaging Adds Little Value in the Diagnosis of Femoroacetabular Impingement Syndrome

Background: Femoroacetabular impingement (FAI) syndrome is an increasingly recognized source of hip pain and disability in young active adults. In order to confirm the diagnosis, providers often supplement physical examination maneuvers and radiographs with intra-articular hip injection, magnetic resonance imaging (MRI), or magnetic resonance arthrography (MRA). Since diagnostic imaging represents the fastest rising cost segment in U.S. health care, there is a need for value-driven diagnostic algorithms. The purpose of this study was to identify cost-effective diagnostic strategies for symptomatic FAI, comparing history and physical examination (H&P) alone (utilizing only radiographic imaging) with supplementation with injection, MRI, or MRA. Methods: A simple-chain decision model run as a cost-utility analysis was constructed to assess the diagnostic value of the MRI, MRA, and injection that are added to the H&P and radiographs in diagnosing symptomatic FAI. Strategies were compared using the incremental cost-utility ratio (ICUR) with a willingness to pay (WTP) of

Polymicrobial Infections in Hip Arthroplasty: Lower Treatment Success Rate, Increased Surgery, and Longer Hospitalization

100,000/QALY (quality-adjusted life year). Direct costs were measured using the Humana database (PearlDiver). Diagnostic test accuracy, treatment outcome probabilities, and utilities were extracted from the literature. Results: H&P with and without supplemental diagnostic injection was the most cost-effective. Adjunct injection was preferred in situations with a WTP of >

The Effect of Patient Comorbidities on Intermediate Outcomes After Total Ankle Arthroplasty

60,000/QALY, low examination sensitivity, and high FAI prevalence. With low disease prevalence and low examination sensitivity, as may occur in a general practitioners office, H&P with injection was the most cost-effective strategy, whereas in the reciprocal scenario, H&P with injection was only favored at exceptionally high WTP (∼

Payment drivers in Medicare patients undergoing total ankle arthroplasty

990,000). Conclusions: H&P and radiographs with supplemental diagnostic injection are preferred over advanced imaging, even with reasonable deviations from published values of disease prevalence, test sensitivity, and test specificity. Providers with low examination sensitivity in situations with low disease prevalence may benefit most from including injection in their diagnostic strategy. Providers with high examination sensitivity in situations with high disease prevalence may not benefit from including injection in their diagnostic strategy. Providers should not routinely rely on advanced imaging to diagnose FAI syndrome, although advanced imaging may have a role in challenging clinical scenarios. Level of Evidence: Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

Possible Implications for Bundled Payment Models of Comorbidities and Complications as Drivers of Cost in Total Ankle Arthroplasty

BACKGROUND Polymicrobial hip arthroplasty infections are a subset of periprosthetic joint infection (PJI) with distinct challenges representing 10%-47% of PJI. METHODS Records were reviewed from all PJIs involving partial or total hip arthroplasty with positive hip cultures between 2005 and 2015 in order to determine baseline characteristics and outcomes including treatment success, surgeries for infection, and days in hospital for infection. Analysis was restricted to patients who had at least 2 years of follow-up after their final surgery or hospitalization for infection. Factors with P-value less than .05 in univariate outcomes analysis were included in multivariable models. RESULTS After multivariable analysis, 28 of 95 hip arthroplasty PJIs which were polymicrobial were associated with significantly lower treatment success, more surgery, and longer hospitalizations compared to PJIs which were not polymicrobial. Patients diagnosed with polymicrobial infection later in treatment (4 of 28) had the lowest treatment success rate, underwent the most surgery, and spent the longest time in hospital. CONCLUSION Polymicrobial periprosthetic hip infection is a particularly devastating complication of hip arthroplasty associated with decreased likelihood of treatment success, increased surgery for infection, and greater time in hospital. Patients with late polymicrobial infection had the worst outcomes. This investigation further characterizes the natural history of periprosthetic hip infections with more than one infectious organism. Patients who present with a subsequent polymicrobial infection should be educated that they have a particularly difficult treatment course and treatment success may not be possible.

Early recovery after hip arthroscopy for femoroacetabular impingement syndrome: a prospective, observational study

Category: Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) has shown durable improvements in pain, function, and quality of life. Patient factors could affect intermediate to long-term outcomes after total ankle arthroplasty, and the impact of common medical comorbidities has not been fully characterized. The purpose of this study was to determine if common preoperative patient comorbidities had an effect on patient outcomes. Methods: Patients undergoing TAA between 1/2007 and 12/2016 were enrolled into a prospective study at a single academic center. Patients completed the following outcome measures before surgery and then in follow-up: AOFAS Hindfoot score, 36-item Short Form Survey (SF-36), Foot and Ankle Disability Index (FADI), and the Short Musculoskeletal Function Assessment (SMFA) score. Patient and operative factors along with pre-operative Charlson-Deyo and Elixhauser comorbidities with at least 10% prevalence across the entire population were assessed for association with changes in outcomes from pre-operative to the patient’s most recent follow-up. A minimum of 2 years of follow-up was required. Factors that met a significance threshold of p<0.05 in univariate analyses were incorporated into multivariable outcome models. Results: A total of 538 patients with an average follow-up of 4.3 years (range, 2 to 10 years) were included. While patients had significantly improved pain and function across all outcomes, smoking was associated with smaller improvements in AOFAS hindfoot score, AOFAS hindfoot function subscale, SF-36 physical summary scale, SF-36 total scale, and SMFA function scale. Prior foot and ankle surgery was associated with smaller improvement in AOFAS hindfoot pain subscale as well as VAS pain. Rheumatoid arthritis was associated with smaller improvement in SF-36 total and physical summary subscale scores while obesity was associated with smaller improvement in the FADI. Smoking had the largest impact on results, and produced a moderate effect size. All other variables had trivial to small effect sizes. Conclusion: While patient outcomes improved significantly after TAR at intermediate duration follow-up, smoking, prior surgery, rheumatoid arthritis, and obesity were risk factors for reduced improvement in outcomes. Smoking was associated with a moderate effect size, but all other factors had only small impact on patient-reported outcomes. Active smokers should be counseled on their risk of smaller improvements in outcomes, and it may be inadvisable to perform TAR on these patients.

Do Patient Risk Factors Impact 90-Day Readmission after Total Ankle Arthroplasty?

Category: Ankle Arthritis Introduction/Purpose: The Comprehensive Care for Joint Replacement model (CJR) provides bundled payments for in-hospital and 90-day post-discharge care of patients undergoing total ankle arthroplasty (TAA). Defining patient factors associated with increased costs during TAA could help refine patient selection strategies and identify modifiable preoperative patient factors that can be addressed prior to the patient entering the bundle. Methods: This study is part of an IRB-approved single-center observational study of patients undergoing TAA from 1/1/2012 to 12/15/2016. Patients were included if they met CJR criteria for inclusion into the bundled payment model and had Medicare as the insurance payer. Costs related to readmissions, diagnosis, and procedures that had been excluded by CJR were also excluded from this financial analysis. All inpatient and outpatient payments beginning at the index procedure through 90 days postoperatively were identified. Patient medical profile including Charlson-Deyo and Elixhauser comorbidity scores, preoperative comorbidities, and perioperative factors were then completed based on institutional data and chart review. Additionally, post-discharge disposition, readmissions, emergency department (ED) utilization, and outpatient plastic surgery consultation were recorded within the 90-day bundled payment period. Results: Out of 199 patients with Medicare payments in the study timeframe, 137 had consented to the study and were analyzed. Baseline and operative characteristics are given in Table 1. Increased length of stay (LOS) at the initial procedure, increased Charlson-Deyo comorbidity score, cerebrovascular disease, and peripheral vascular disease were significantly associated with higher payments. Discharge to skilled nursing facility (skilled nursing facility), admissions, ED visits, and wound complications were significant drivers of payment. Conclusion: Increased Charlson-Deyo score and vascular disease along with increased LOS were associated with increased payments from Medicare. Discharge to SNF, readmission, ED visits, and wound complications considerably increased payments. This study identifies the relationship between patient profile and increased financial burden, highlighting the potential utility of pre-operative mitigation of modifiable risk factors and stratification of payments based on patient profile. Lastly, reducing rates of SNF placement, readmission, ED visitation, and wound complications are targets for decreasing costs for patients undergoing TAA.

Inpatient Consults and Complications During Primary Total Joint Arthroplasty in a Bundled Care Model

Background: The Comprehensive Care for Joint Replacement (CJR) model provides bundled payments for in-hospital and 90-day postdischarge care of patients undergoing total ankle arthroplasty (TAA). Defining patient factors associated with increased costs during TAA could help identify modifiable preoperative patient factors that could be addressed prior to the patient entering the bundle, as well as determine targets for cost reduction in postoperative care. Methods: This study is part of an institutional review board–approved single-center observational study of patients undergoing TAA from January 1, 2012, to December 15, 2016. Patients were included if they met CJR criteria for inclusion into the bundled payment model. All Medicare payments beginning at the index procedure through 90 days postoperatively were identified. Patient, operative, and postoperative characteristics were associated with costs in adjusted, multivariable analyses. One hundred thirty-seven patients met inclusion criteria for the study. Results: Cerebrovascular disease (intracranial hemorrhages, strokes, or transient ischemic attacks) was initially associated with increased costs (mean,