What Are Your Perioperative Protocols for Primary TKA Patients?

    Dr. Denis Nam, Dr. Ran Schwarzkopf, and Dr. Scott Sporer respond to questions from ICJR about perioperative management of primary total knee arthroplasty patients, including BMI cutoff, antibiotic prophylaxis, and use of tranexamic acid.

    ICJR: Do you have a BMI cutoff for considering patients for primary total knee arthroplasty (TKA)? Is it a hard cutoff or a soft cutoff? If the patient’s BMI has decreased but is still above your cutoff, will you perform surgery?

    Denis Nam, MD, MSc: I would describe my BMI cutoff as “soft.” My target BMI is less than 40 kg/m2, but I explain to patients that this is really a continuous scale and that even a BMI of more than 35 kg/m2 can increase their risk of perioperative complications. Thus, the more weight they can lose, the better.

    I counsel patients with a BMI over 40 kg/m2 on the benefits of weight loss and ask them to speak to a nutritionist. Our medical center has a lifestyle program to which patients can be referred, and it includes a nutritionist and bariatric surgeon for evaluation and counseling. If a patient has made an earnest attempt to lose weight, I will often still proceed even if their BMI remains greater than 40 kg/m2, depending on the presence of other co-morbidities and risk factors.

    Emerging evidence shows that a patient’s body morphology is a greater predictor of risk rather than BMI alone with respect to infection. [1] If a patient has a high BMI but a very thin knee, I do not think the risk of infection is as high as if they have a large soft tissue envelope around the knee.

    That being said, obese patients live at a heightened inflammatory state due to their adipose tissue and, thus, are still likely at increased risk of perioperative complications including infection. Therefore, it is important to consider a patient’s body habitus and other co-morbidities that together may help determine the risk of complications and infection.

    Ran Schwarzkopf, MD, MSc: I do not have a hard cutoff, but I start evaluating the patient’s modifiable and non-modifiable co-morbidities at a BMI above 35. When patients have a BMI above 40, I start discussing a delay in surgery until they are better optimized, especially if they have other co-morbidities such as metabolic syndrome.

    I will procced to surgery with a BMI above 40 in patients who do not have other risks for wound complications and infection, especially active working patients whose osteoarthritis may hinder their ability to work and provide for their families.

    Scott M. Sporer, MD, MS: I have transitioned from a definitive “hard stop” BMI cutoff of 40 to a “soft stop.” As more data regarding BMI become available, we’re learning that infection risk is less about the overall BMI and is more related to the patient’s concomitant medical co-morbidities.

    Patients with a BMI above 40 are now referred to a medical optimization clinic that includes a multidisciplinary team to address weight loss. I will not operate on patients with a BMI above 40 unless they have been evaluated in the medical optimization clinic and all other modifiable risk factors have been optimized.

    ICJR: Do you operate on primary TKA patients who are smokers, or do you require them to stop smoking before surgery? If smoking cessation is required, for how long before surgery? Do you do cotinine testing? If so, do you delay surgery if testing shows they’ve been smoking?

    Dr. Schwarzkopf: I discuss smoking cessation with all my patients and refer them to our smoking cessation program. I aim for them to stop smoking 6 weeks prior to surgery. Currently, I do not delay surgery for patients who did not stop smoking unless they have multiple other risk factors. I do not currently test them prior to surgery.

    Dr. Sporer: Smoking, for me, is a definitive hard stop. The data surrounding smoking and increased risk of infection are extremely strong. I require all patients to cease smoking a minimum of 6 weeks in advance of their elective surgery. I also inform them that their surgery will be canceled if they do not comply with these recommendations.

    All patients are seen for medical clearance 2 weeks prior to surgery. If there is any suspicion of ongoing smoking, cotinine testing will be added as part of their preoperative bloodwork. If positive, the surgery will be canceled.

    Dr. Nam: I counsel all patients on the negative effects of smoking and tobacco use and insist that they stop the use of all tobacco products at least 1 month before surgery. I ask them to speak to their primary care physician for smoking cessation aids such as nicotine patches or varenicline. Furthermore, the aforementioned “lifestyle program” at our center can also provides guidance on smoking cessation. I rarely do cotinine testing, but I should. For better or worse, I usually take patients at their word.

    ICJR: Before performing primary TKA, do you wean patients from any preoperative opioids they’d been taking to manage osteoarthritis (OA) pain? Do you change your pain management protocol to take into account their preoperative use of opioids?

    Dr. Sporer: Patients who are taking preoperative opioid medication are strongly advised to stop their medications prior to surgery. In general, I see 2 different types of patients taking opioids prior to surgery:

    • The first group consists of patients who take an occasional opioid, typically prescribed by their primary care physician. Most of these patients will easily stop their medications prior to surgery and as a result, I do not alter the postoperative pain management protocol.
    • The second group consists of patients with chronic pain, often unrelated to knee OA, who are managed in a pain clinic. For this group, we involve the patient as well as the pain physician in a postoperative pain management protocol. We will not operate on these patients until a written plan – agreed on by all parties – is in place. In general, these patients have a modified postoperative pain regimen, which frequently results in escalated doses of opioids.

    Dr. Nam: I refer patients who have a chronic history of significant opioid use, such as oxycodone use greater than 3 months, to our pain management service in an attempt to wean them off of their preoperative opioids. Patients who are taking a less-potent opioid such as tramadol are encouraged to discontinue this medication. I inform all patients that preoperative opioid use is associated with worse clinical outcomes and will only make it more difficult to control their pain postoperatively.

    Dr. Schwarzkopf: I do not wean patients myself, but I do discuss the importance of decreasing their consumption of opioids to help better control their pain after the surgery. If a patient is seeing a pain management physician, I will discuss with the physician the goal of optimizing the patient prior to surgery. We adjust the postoperative pain management plan to accommodate preoperative opioid use. In some cases, we involve our in-house pain management service.

    ICJR: Do you routinely screen primary TKA patients for Staphylococcus infection preoperatively? If so, how far in advance of surgery? How do you treat those who are positive?

    Dr. Nam: I do not perform screening for Staphylococcus or methicillin-resistant Staphylococcus aureus (MRSA) infection in my practice. We have moved to a “treat everyone” mentality where all patients in our practice will use chlorhexidine soap and mupirocin nasal swabs for 5 days preoperatively. Patients who report a history of MRSA will receive vancomycin in addition to cefazolin (Ancef) perioperatively.

    Prior investigations have shown that the cost of screening, treating, and re-testing patients is actually more expensive than a treat everyone program. With a treat everyone program, however, we may miss patients who are colonized with MRSA and who could benefit from receiving vancomycin perioperatively. This is the primary downside to our “treat everyone” protocol.

    Dr. Schwarzkopf: We screen all patients at their pre-admission testing visit about 2 weeks before surgery. All positive patients undergo nasal decolonization on the day of surgery and receive vancomycin plus gram-negative coverage instead of cefazolin.

    Dr. Sporer: We routinely screen all patients undergoing primary TKA for Staphylococcus and MRSA. This is done 2 weeks prior to surgery at their preoperative medical evaluation. All patients who test positive for Staphylococcus infection (methicillin-sensitive Staphyloccocus aureus or MRSA) are treated with 10 doses of mupirocin. Patients who test positive for MRSA are also placed on contact precautions and are given vancomycin in addition to a first-generation cephalosporin for antibiotic prophylaxis.

    Our protocol is below:

    ICJR: What is your standard protocol of antibiotic prophylaxis in primary TKA patients? What about for highrisk patients? What do you do when a patient reports a penicillin allergy?

    Dr. Sporer: We use a standardized protocol for antibiotic prophylaxis in primary TKA patients.

    Dr. Nam: Our standard protocol is to use cefazolin preoperatively and for 24 hours postoperatively. Patients with recent hospitalizations or a history of MRSA also receive vancomycin perioperatively. A multicenter study is currently underway to assess whether a single dose of antibiotics preoperatively is just as effective as our current standard of 24 hours of prophylactic antibiotics.

    Patients who report a pencillin allergy are sent to an allergist for testing to ensure they have a true penicillin allergy. Most patients who report an “allergy” do not have a true anaphylactic reaction and would benefit from receiving cefazolin as it is more effective in preventing infection perioperatively than vancomycin or clindamycin alone.

    Even if a patient has a potential pencillin allergy, the likelihood of cross-reactivity with cefazolin is very low. Thus, we prefer to use cefazolin as often as possible unless a patient has a true penicillin allergy confirmed with testing.

    Dr. Schwarzkopf: We treat with 3 doses of cefazolin unless the patient has a true penicillin allergy. Then, we treat with 2 doses of vancomycin and add gram-negative coverage, typically 1 dose of gentamicin or aztreonam preoperatively.

    ICJR: What is your deep vein thrombosis (DVT) prophylaxis protocol for primary TKA patients? Which drugs do you use and in which patients, and do you prescribe mechanical prophylaxis as well as chemoprophylaxis?

    Dr. Nam: My standard DVT prophylaxis protocol is 325 mg of enteric-coated aspirin twice a day. Although I have not yet switched to low-dose aspirin, I agree with data from The Rothman Institute indicating that low-dose aspirin is likely equally effective based on its mechanism of action. In addition, low-dose aspirin likely has decreased gastrointestinal side effects.

    I will use a stronger anticoagulant in patients who report a history of DVT or pulmonary embolism (PE), who are currently take more-potent chemical anticoagulants (such as warfarin or Factor Xa inhibitors) usually for cardiac indications, or who have significant immobility or active cancer.

    We use mechanical compression pumps while patients are in the hospital, but they are not discharged with a pump.

    Dr. Schwarzkopf: We treat all standard-risk patients with 81 mg of aspririn twice a day for 28 days. We currently prescribe mechanical devices for patients while they are in the hospital, but not at discharge. In the past, however, we did prescribe mechanical prophylaxis post-discharge for 14 days.

    Dr. Sporer: Below is our DVT prophylaxis protocol:


    • Sequential compression device (SCD) or foot pump worn in the OR during surgery

    Inpatients Postoperatively

    Standard-risk patients

    • 325 mg of aspirin PO twice a day with SCD or foot pump for prophylaxis of venous thromboembolism (VTE); aspirin alone is not an acceptable VTE prophylaxis
    • First dose given the day of surgery
    • H2 blocker or proton pump inhibitor given in conjunction with aspirin

    High-risk patients (prior history of VTE, morbid obesity BMI>40, active smoking, active cancer treatment, or patient refuses or unable to obtain pumps)

    • Wararin, rivaroxaban, or other chemoprophylaxis per medical consult
    • SCD or foot pump while in the hospital

    Outpatients Postoperatively

    Standard-risk patients:

    • 325 mg of aspirin PO twice a day for 4 weeks
    • First dose given the day of surgery by 10:00 pm
    • H2 blocker or proton pump inhibitor in conjunction with aspirin

    High-risk patients (prior history of VTE, morbid obesity BMI>40, active smoking, active cancer treatment, or patient refuses or unable to obtain pumps)

    • Warfarin (goal INR 1.8-2.2) or other chemoprophylaxis per medical consult

    ICJR: Do you use tranexamic acid (TXA) routinely in your primary TKA patients? Do you have any exclusions? What is your standard dosage – route and amount? Have you had pushback from your anesthesiologists over intravenous (IV) TXA, particularly with patients on an anticoagulant, and how have you overcome it? What is your transfusions rate and how has it changed since using TXA?

    Dr. Schwarzkopf: Most patients receive 1 gram of IV TXA at the start of the procedure and 1 gram of IV TXA at the end of the procedure unless they have:

    • History of DVT or PE
    • History of coronary artery disease with coronary stents
    • History of cerebrovascular accident
    • Histery of hypercoagulable state
    • Current anticoagulation treatment

    These patients receive 3 grams of topical TXA in 100 mL of saline preoperatively. We are looking to decrease some of these restrictions for IV treatment.

    Our transfusion rate has been almost non-existent since we started using TXA. We do not routinely order a complete blood count after a primary TKA.

    Dr. Sporer: We use TXA in all primary TKA patients with the exception of patients who report an allergy to TXA. Patients receive 1 gram of IV TXA prior to incision and another 1-gram IV dose 4 hours after surgery. The exception is outpatients: Their second dose is oral TXA.

    We initially had resistance from both anesthesia and the hospital pharmacy for TXA use in patients with a history of DVT, PE, cerebrovascular accident, myocardial infarction, or cardiac stent. With more data now available on the safety and efficacy of this drug in primary total joint arthroplasty patients, we can give TXA to all patients. Ironically, I believe that these patients are the ones who are most likely to derive the greatest benefit from this medication.

    Without a doubt, our transfusion rates have plummeted since the use of TXA. I am not aware of any primary TKA patients who have required a blood transfusion over the past several years.

    Dr. Nam: The majority of our patients receive oral TXA (1.95 gram) administered approximately 2 hours preoperatively. This is a single preoperative dose, without any intraoperative or postoperative doses.

    I do not give TXA to patients with a history of DVT or PE. There is emerging evidence from Mayo Clinic that the use of TXA is safe even in patients deemed at “high risk” for thromboembolic complications. I have not yet gone to using it in all-comers, although I believe that it is likely safe to do so unless a patient reports an allergy to TXA.

    We do not use IV TXA at our institution. I do not use intra-articular TXA in high-risk patients as preliminary data suggest that systemic absorption of intra-articular TXA may actually reach systemic levels close to that of IV TXA.

    I have used TXA since starting my practice and thus do not have a comparison of pre-TXA versus post-TXA transfusion rates, but I believe the use of TXA has been a game-changer in perioperative blood management for TKA patients.

    Author Information

    Denis Nam, MD, MSc, is Associate Professor of Orthopaedic Surgery at Rush University Medical Center, Chicago, Illinois, and Medical Director of Great Lakes Surgical Suites, Munster, Indiana.

    Ran Schwarzkopf, MD, MSc, is Associate Professor in the Department of Orthopaedic Surgery, Adult Reconstructive Division, at NYU Langone Health, New York, New York.

    Scott M. Sporer, MD, MS, is Professor of Orthopaedic Surgery at Rush University Medical Center, Chicago, Illinois.


    Dr. Nam, Dr. Schwarzkopf, and Dr. Sporer have no disclosures relevant to this article.


    1. Watts CD, Houdek MT, Wagner ER, Taunton MJ. Subcutaneous fat thickness is associated with early reoperation and infection after total knee arthroplasty in morbidly obese patients. J Arthroplasty. 2016 Aug;31(8):1788-91. doi: 10.1016/j.arth.2016.02.008. Epub 2016 Feb 8.