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Identifying Joint Replacement Patients at Risk for Complications

Two studies produce models to predict possible complications following hip and knee replacement surgery.

Doctors at the University of Pennsylvania Perelman School of Medicine have developed two new ways to identify candidates who are at risk for complications following hip and knee replacement surgery. "There is a need to better identify and predict post-operative complications so we can intervene and provide timely follow-up care," says Gwo-Chin Lee, MD, Assistant Professor of Orthopaedic Surgery and senior investigator for two studies. "Total hip and knee replacements are very common, but they also can pose significant health risks to certain patients, especially older adults."

Complications Following Surgery.
In one study, Dr. Lee's team studied the results of 1,012 patients who underwent total hip or knee replacement over a 10-month period. Of the 70 patients who developed serious complications, most had cardiopulmonary problems.

Of those 70 patients, 11 suffered setbacks within 24 hours; 59, more than 24 hours later. If the 59 patients had undergone same-day or shortstay (overnight) surgery, they would have developed the complications at home and been placed at even greater risk.

As a result of the findings, a scale was developed that will allow orthopaedic surgeons to determine if a patient is a candidate for same-day or short-stay procedures, or if that person should be admitted for traditional-duration surgery and recovery. Patients who have at least one risk factor, such as chronic obstructive pulmonary disease (COPD), congestive heart failure, coronary artery disease, or cirrhosis, should not be considered for either outpatient or overnight-stay total knee or hip replacement.


STEVEN A. OLSON, MD, FACS, Professor, Department of Orthopaedic Surgery; Pelvis and Hip Reconstruction; Hip Preservation Surgery, Duke

Evolving Models of Care Enable Safer Joint Replacement
“As the technology for hip and knee replacement improves, the indications have expanded. In many cases, patients are healthy enough to have only a single overnight stay. Some centers have even begun to consider sending carefully selected patients home the day of joint replacement. These trends highlight the importance of Dr. Lee's investigations. Identi-fication of patients at risk for cardiac events in the perioperative period is important for patients, surgeons, and the medical centers they work in. These studies provide insight to make the evolving models of care for joint replacement safer—and that is better for all of us.”

Admission to Critical or Intensive Care.
In a second study, Dr. Lee and Dr. Maxwell Courtney studied the records of 738 patients who had undergone the same types of hip or knee replacement surgery. Those who had to be admitted to intensive care or critical care after the procedures had a history of COPD, congestive heart failure, coronary artery disease, or chronic kidney disease, or needed medications to raise blood pressure during the procedure, or they lost more than 1,000 milliliters of blood during surgery.

Based on the findings, researchers developed the Penn Arthroplasty Risk Score (PARS) to predict which patients would require intensive or critical care after either surgery. The new model replaces an older one that covered fewer medical conditions, and none that involved intraoperative (during surgery) procedures.

"Under the previous model, one in four patients were preemptively admitted to ICU," says Dr. Lee. "However, we found that only 22 percent of the patients ultimately required such stepped-up intervention. By incorporating certain factors into the model, such as significant blood loss and the need to raise the patient's blood pressure, we have refined the selection criteria for post-surgery admission to the ICU."

Lower Cost, More Available Beds.
Use of the PARS tool will result in fewer patients being routinely admitted to intensive care and critical care units after joint replacement surgery, which will result in lower costs without compromising patient safety. It will also ensure that scarce critical care beds are available for those who need them most.

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