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.”
Infection can lead to arthrofibrosis so patients with arthrofibrosis will have higher rates of infection and revisions.
How many MUA’s are performed for stiffness that has developed in a knee BECAUSE of unrecognized, low grade subclinical infection?
June 12, 2023
Robert E. Booth, Jr., MD, Orthopaedic Surgery Total Knee Replacement and Revision Medical Director
Letter to the Editor Orthopedics This Week
Dear Robin:
As you know, I am among your many admirers and a faithful reader of “Orthopaedics This Week”. I believe this is the first letter of complaint which I have ever sent you, but I feel that the review on December 13, 2022 of the article on “Manipulation Following Total Knee Arthroplasty… ” betrays an improper title about an article which probably did not deserve publication in the first place.
The article at issue is “The Journal of Arthroplasty: “Manipulation Following Primary Total Knee Arthroplasty is Associated with Increased Rates of Infection and Revision”.
To begin, I feel that the article in question was not meritorious of publication, particularly given the exceptional editorial staff which the Journal of Arthroplasty enjoys. That article analyzes 142,440 patients who had a primary total knee which became stiff and – with or without arthroscopy/arthrotomy – went on to manipulation. The patients who were manipulated had an incidence as high as 10% infection and 13% revision within three years. These numbers are, of course, unconscionable, and merit detailed analysis. Because it is a review of a very large number of Medicaid total knees, it escapes the analysis of infection, poor surgery, and mitigating factors which an individual surgeon could offer. Mere volume does not obviate true analysis. While the authors give lip service to the need to analyze these patients before manipulation, it is totally unknown whether any of them had X-Rays looking for heterotopic ossification, aspiration for alpha-defensin levels, or a simple radiographic analysis to determine if the surgery was poorly done. Indeed, like so many articles of large group analysis, the improper and implicit presumption is that all these knees were perfectly done and that the manipulations were not required because of biological or technical errors. The paper is a mildly interesting mathematical analysis documenting what we all know already, which is that patients with problematic knees who undergo manipulation often require further treatment. It is sometimes said that a “poly change alone is rarely the last operation”, and the thesis of this paper deserves similar understanding.
While I did not write to the Journal of Arthroplasty, what concerns me most is that YOUR review of this article is titled “TKA: Manipulation Under Anesthesia Boosts PJI, Revision Risk?” This title, and the article that follows it, are dangerous in that they strongly suggest that the manipulation is somehow responsible for the parlous results of poor surgery and undiagnosed infection. It should actually be read in the reverse, in that infection and inadequate surgeries increase the incidence of manipulation, not the opposite.
What should come of this is an understanding among surgeons that stiff knees merit the same evaluation that a revision would demand, such as X-Rays looking for heterotopic ossification, serology, Synovasure, etc. The title in your analysis of the article is grist for the legal mill in that it implies that the manipulation itself may be the cause of infection or revision.
Rather than a criticism, I would hope that you take this as an opportunity to advance our art and treat problematic knees – despite the legendary myopia of the operating surgeon – as something which requires more analysis despite its proximity to the index arthroplasty.
Best regards,
Bob Booth
Robert E. Booth, Jr., M.D.
REB:dd