Research symposium examines economics, demographics of orthopaedic infections

Maureen Leahy

As the U.S. healthcare system transitions from fee-for-service to value-based reimbursements, physicians are increasingly concerned that they might be penalized when adverse events occur over which they may have little control. That concern may be justified, according to Antonia F. Chen, MD, MBA, of the Rothman Institute at Thomas Jefferson University, Philadelphia. Alternative payment models such as bundled payments, she noted, do not take infections into account.

Dr. Chen made her remarks during the recent AAOS/Orthopaedic Research Society (ORS) research symposium, Musculoskeletal Infection: Where are we in 2014? The symposium brought together experts from multiple disciplines to address, among other topics, the economic implications and demographic influences of orthopaedic infections.

Bundling and infection
In the bundled payment model, a single payment covers all services related to an episode of care. If the costs of care turn out to be less than the predetermined bundled rate, the difference is shared among the providers. Conversely, if costs exceed the bundled payment, the providers share the loss.

“Orthopaedic surgical patients who incur infections increase the financial burden of all surgical procedures, negating the potential profit gained from minimizing costs in procedures without complications,” Dr. Chen said. “In this era of bundled payments, therefore, surgeons must be especially cautious to prevent infections and carefully evaluate patients who are at high risk for developing infections.”

Minimizing risk
To help minimize the risk of infection, Dr. Chen recommends careful patient selection, preoperative risk modification, and/or surgical delay. She noted that patients who smoke, are diabetic, or are obese are at higher risk for development of surgical infections. Physicians should counsel these patients on these risks and recommend possible preventive techniques, such as smoking cessation programs, nutrition counseling, or weight-loss programs, before scheduling surgery. In some patients with high comorbidities or risk factors that are not modifiable, surgical delay may be
recommended.

“Bundled payments are here to stay, and infection is not taken into account. Future actions must be taken to ensure that patients at high risk of infection are not marginalized and denied surgery. At the same time, orthopaedic surgeons should not be penalized for operating on high-risk patients,” Dr. Chen stressed.

Sex and PJI
Although numerous patient-related characteristics are known risk factors for deep infection, no consensus exists regarding the effect of sex on periprosthetic joint infection (PJI) rates after hip and knee arthroplasty, noted Elie Ghanem, MD. Dr. Ghanem and his colleagues from Geisinger Medical Center, Danville, Pa., sought to identify differences in male and female characteristics including comorbidities that may account for disparities in deep infection between the genders.

The retrospective study included 9,751 primary and revision total hip and knee arthroplasties performed at a single institution between 2006 and 2013; in that study, PJI developed in 213 patients. Data analyzed included patient age, sex, body mass index (BMI), and various comorbidities.

Multivariate analysis revealed that male sex, insulin use, and BMI are independent risk factors for infection. Interestingly, rheumatoid arthritis—which is more common in women—was not an independent risk factor for deep infection, possibly due to the improved treatment modalities initiated early on by rheumatologists, Dr. Ghanem noted.

“Based on our study, we concluded that male sex is a significant risk factor for developing PJI,” Dr. Ghanem said. “We found that men are more likely than women to be smokers and diabetics who use insulin. These tendencies in social behavior and nutritional habits—which can be addressed through lifestyle modification and counseling—shed light on the disparity in infection rates between the sexes.”

The researchers are hopeful that a future study will help them determine if males have a genetic predisposition for PJI. “Identifying the gene or phenotype that, in combination with comorbidities and health characteristics, can predispose to PJI would greatly improve the risk stratification scheme we have. In the long run, it could also potentially assist us in developing gene therapy,” Dr. Ghanem said.

Costs to the system
The growing incidence of PJI is a major contributor to the increasing costs of health care in the United States. According to presenter David Jaekel, PhD, a senior associate with Exponent, an engineering and scientific consulting firm, the annual cost of total joint revision surgeries due to infection increased from $320 million in 2001 to $566 million in 2009; costs are projected to exceed $1.62 billion by 2020.

“Although the costs per case of PJI were mitigated between 2001 and 2009 by reductions in the length of hospital stay,” noted Dr. Jaekel, “the overall national burden of PJI is increasing due to the expanded utilization of hip and knee arthroplasty.”

“The financial implications of these trends are extraordinary,” agreed presenter Christina Gutow-ski, MD, MPH, a third-year orthopaedic surgery resident at Thomas Jefferson University Hospital. “By 2020, more than 60,000 cases of PJI are projected to occur on an annual basis. The mean charge associated with treating PJI has risen to more than $80,000 in 2011 and has been accompanied by an increasing prevalence of methicillin-resistant infections and more aggressive, yet expensive, treatment algorithms. This will put a severe strain on payers going forward.”

Disclosure information: Dr. Chen—Novo Nordisk, SLACK Inc. Dr. Ghanem—no conflicts.

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

About the AAOS/ORS Musculoskeletal Infection Research Symposium
The AAOS/ORS Research Symposium, Musculoskeletal Infection: Where are we in 2014?, was held May 8–10, 2014, in Rosemont, Ill. Co-chaired by Javad Parvizi, MD; Michael Archdeacon, MD; and Paul Manner, MD, FRSC, the event provided the latest in evidence-based knowledge for improving the diagnosis and treatment of musculoskeletal infection, including orthopaedic periprosthetic and posttraumatic/postoperative infections. The symposium’s goal was to differentiate the various forms of musculoskeletal infections in terms of microbiology, cellular biology, and pharmacology; compare observed disparities between affected patient groups; and develop consensus statements for the diagnosis and treatment of specialty-specific orthopaedic infections.

Participants included more than 60 orthopaedic surgeons, young investigators, researchers, bioengineers, industry representatives, and other medical specialists. In 10 sessions over 2 days, the following topics were addressed:

• Economic and Regulatory Perspective
• Demographic Influence on Incidence of Orthopaedic Infections
• Prevention of Orthopaedic Infections: Strategies that Work, Systems Integration
• Diagnosis of Orthopaedic Infections: Challenges, Promise of Molecular Techniques, and Practice-Based Approach
• Confusions for Treatment
• Looking Ahead: Plan of Regulatory Bodies and Societies
• Novel Developments