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Patient risk factors may lead to poor outcomes and complications after orthopaedic procedures. In the patient shown here, multiple medical comorbidities after revision total knee arthroplasty led to full-thickness soft tissue loss and additional procedures.
Courtesy of Samir Mehta, MD

AAOS Now

Published 6/1/2016
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Jennie McKee

Examining Patient Risk Factors that May Affect Outcomes

Factors classified as modifiable, nonmodifiable, and psychosocial play important roles
"There has been more and more published on patient-related issues that may affect outcomes. This is of particular importance as we move forward with the Comprehensive Care for Joint Replacement (CJR) Model and bundled payments," said Samir Mehta, MD, chief of the Orthopaedic Trauma & Fracture Service at the University of Pennsylvania.

Dr. Mehta outlined patient risk factors, such as those deemed modifiable and nonmodifiable, as well as various psychosocial factors that may ultimately affect some of the outcomes upon which the quality of orthopaedic care is measured. He spoke during the 2016 AAOS Now Forum, "How Good an Orthopaedist Are You? Risk Stratification & Quality-of-Care Reporting," moderated by AAOS Now Editor-in-Chief Eeric Truumees, MD, held after the 2016 AAOS Annual Meeting in Orlando, Fla.

"Modifiable" versus "nonmodifiable" risk factors
Dr. Mehta began his analysis of patient risk factors and their effects on outcomes by exploring what constitutes an ideal patient encounter with a provider.

"You start with some kind of disease state, move forward with presentation to the provider, get a diagnosis, have an intervention, and there's a positive outcome from the intervention through continued follow-up," he said. "Then, the episode of care ends. But we know there are many things that can affect this pathway, in terms of timing and access to care, and there are things that may affect your diagnosis or take you down different paths." Ultimately, he noted, the goal is for orthopaedists to navigate these factors with the help of evidence-based guidelines to achieve good patient outcomes.

But more typically, acknowledged Dr. Mehta, patient encounters proceed in a less ideal way, with access and timing issues sometimes affecting the provider's ability to identify the correct diagnosis.

"There are certain things that we know for a fact affect outcomes: the literature is really clear, both on the basic science side and on the clinical side," he said. "It's been shown that factors such as smoking, diabetes, obesity, preoperative activity level, and vascular disease clearly have an impact on postoperative outcomes."

And yet, modifiable risk factors may not be as easily modified as one might hope, noted Dr. Mehta. One example is that of a patient with a body mass index (BMI) that is very high with bilateral degenerative knee disease.

"We know that obesity affects outcomes in arthroplasty, but is it realistic to ask a morbidly obese (BMI ≥40) patient to modify that risk factor and get his or her BMI below 30, which we know will improve the patient's outcome?" he asked. "So when we talk about modifiable risk factors, we have to ask ourselves from a patient-centric direction, are they really modifiable?"

Psychosocial factors
Other factors that can greatly affect outcomes are those deemed "psychosocial," noted Dr. Mehta, pointing to research recently performed by David Ring, MD, PhD, and fellow researchers.

In a recently published study from Ring et al involving 155 patients, researchers assessed the relationship between psychosocial factors such as health anxiety, depression, and catastrophic thinking and the total area marked painful and numb on hand diagrams. Patients also provided input via demographic, condition-related, and psychosocial questionnaires. The researchers found that the total area patients marked on the pain diagram was linked to catastrophic thinking, depression, and health anxiety. The sole predictor of marked pain area was catastrophic thinking, which accounted for 10 percent of variance in the hand pain diagram. In addition, the researchers found that the interval between symptom onset and the office visit, receiving a diagnosis of carpal tunnel syndrome, and catastrophic thinking were each independently associated with the total area marked by patients on the hand numbness diagram.

Thus, said Dr. Mehta, the study showed that "patients who have issues with managing catastrophe and have been diagnosed with difficulty in coping had significantly larger affected areas on their pain diagrams compared to patients who have better coping strategies.

"This is one of many publications that has come out looking at depression and other factors that affect the presentation as well as the outcome of various upper extremity conditions," he continued. "Researchers have shown that, in patients who have severe depression, carpal tunnel surgery really does not have a good outcome, even though [the surgeon] decompresses the nerve."

Other factors that fall into the psychosocial realm are related to worker's compensation, managing patient expectations in the preoperative setting, demographics, and pain management, all of which have been shown to have an impact on outcomes after surgical intervention, stated Dr. Mehta.

"So, when you think about these, you realize it's more than just the diagnosis and a patient's medical comorbidities that may have an impact," he said. "We know the story doesn't end with understanding that there are factors a patient can bring into the episode of care that will affect their outcome—there's also the burden of disease."

He pointed to a recent study by Heather A. Vallier, MD, and colleagues that found that psychiatric illness is common among patients with orthopaedic polytrauma and is linked with poor outcomes. In the study, which involved 332 skeletally mature patients with surgically treated axial and/or femoral fractures as well as injuries to other body systems, the researchers identified preexisting psychiatric disorders in 130 patients (39.2 percent), including depression and substance abuse. According to the study results, depression was an independent predictor of increased complications.

When considering the results of studies such as this one, noted Dr. Mehta, "you have to ask yourself, 'Is it a chicken or egg phenomenon—ie, is it the disease burden that results in some of the psychosocial factors that then can affect outcomes, or vice versa, or a combination of the two?'"

In conclusion, he said, "the reality is that when a surgeon looks at a patient they have operated on, it's hard to do so without some therapeutic bias that the intervention performed would have a positive effect. However, it is really the patient, not the surgeon, who is in the best position to determine whether a good outcome has been achieved from orthopaedic care."

Jennie McKee is the managing editor of AAOS Now. She can be reached at mckee@aaos.org