TKA: Manipulation Under Anesthesia Boosts PJI, Revision Risk?

When performing total knee arthroplasty (TKA), manipulation under anesthesia can raise infection and revision risk, says new work published in the September 30, 2022, edition of The Journal of Arthroplasty. “Manipulation Following Primary Total Knee Arthroplasty is Associated With Increased Rates of Infection and Revision” involved 5% of the Medicare database between 2005 and 2019.

Co-author Arthur L. Malkani, M.D., chief of adult reconstruction at the University of Louisville in Kentucky and study co-author explained the genesis of the study to OTW, “Contracture or stiffness following TKA has been found to be responsible for approximately 28% of 90-day hospital readmissions.”

“There have been articles in the past written on risk factors for postoperative stiffness following TKA. There is not an abundance of literature using the large Medicare database on patients undergoing manipulation under anesthesia focusing on the incidence of revision surgery, prosthetic joint infection (PJI), and timing of manipulation under anesthesia.”

“We identified 142,440 patients who underwent primary TKA with 3,652 patients (2.6%) requiring manipulation under anesthesia. We compared the manipulation under anesthesia group to a control group that did not require manipulation under anesthesia evaluating the incidence of revision surgery and PJI.”

“Revision risk was significantly greater in the manipulation under anesthesia group at 1-,2-, and 5-year time periods with a hazard ratio (HR) of, 3.1, 3.90, and 3.22, respectively. PJI was also significantly greater in the manipulation under anesthesia group with a HR of 2.2, 2.2, and 2.1 at 1,2, and 5 years, respectively. The incidence of manipulation under anesthesia was higher in Black versus White individuals, 4.1 versus 2.5%.”

Flexion an Evolving Target?

“In reviewing the literature for this study,” said Dr. Malkani to OTW, we were surprised to the lack of consensus in the literature on the ideal timing for manipulation under anesthesia. The majority of published articles on manipulation under anesthesia following TKA have utilized lack of 90 degrees of flexion at six weeks as an indication for manipulation under anesthesia.”

“In the 1980s, 90 degrees following TKA was considered a good result. However, at present with patients who want to pursue a more active lifestyle, 90 degrees of knee flexion following primary TKA may not be a satisfactory result especially if they had greater motion preoperatively.”

“In an attempt to provide greater postoperative motion for improved function, some authors have used lack of 110 degrees of knee flexion at six weeks as their criteria for manipulation under anesthesia. Given the limitations of the Medicare database, we do not have the exact indications used for manipulation under anesthesia in this study. Approximately 30% of patients underwent manipulation under anesthesia beyond three months of the index procedure which can be challenging since the knee can get fairly by three months.”

Role of Race, Socioeconomics?

“We were also concerned about the increased risk of periprosthetic joint infection in the manipulation under anesthesia group. Did some of the patients undergoing manipulation also have an underlying periprosthetic joint infection which became more symptomatic at a later time period?”

“In addition, we were concerned by the significant increase in both manipulation under anesthesia and revision incidence in Blacks compared to Whites. Further work is needed to better understand the role of race and socioeconomic status on outcome and complications following TKA.”

As for how this study has influenced his work, Dr. Malkani told OTW, “We try to preoperatively identify patients at risk for manipulation under anesthesia and counsel them accordingly on the increased risk for manipulation under anesthesia, periprosthetic joint infection, and revision incidence. We also monitor them closely in conjunction with our physical therapist and provide early manipulation under anesthesia if they fail to progress accordingly. Additional work is needed to determine the ideal indications and timing of manipulation under anesthesia along with factors leading to increased incidence of periprosthetic joint infection and revision surgery in patients with stiffness following primary TKA.”