The first of the three studies, “Aspirin Versus Potent VTE Chemoprophylaxis (VTEC) in Total Knee Arthroplasty: Reduced Postoperative Pain and Complications with Aspirin Use,” examined the experience of total knee arthroplasty (TKA) patients with postoperative pain who were also taking blood thinners. The study included 28,169 patients treated between 2016 and 2023; 18,413 received aspirin while 9,756 received a potent VTE.. Patients were monitored for 90 days following their procedure. The findings suggest that aspirin should be considered the preferred option for reducing postoperative pain in TKA patients.

Patients on more-potent blood thinners tend to experience more pain, swelling and inflammation after surgery, said Brian P. Chalmers, MD, a hip and knee surgeon at HSS and one of the study’s authors. “We have always known that non-steroidal anti-inflammatory medications can improve patients’ swelling and inflammation after surgery. However, the traditional thought and belief has been that we should avoid those in patients on anticoagulation. Our data show there is less risk and less postoperative pain when these patients are utilizing aspirin.”   

A second study, “The Effect of Concomitant Use of Potent Anticoagulation and Anti-Inflammatories on Early Outcomes of Total Hip Arthroplasty,” retrospectively evaluated 5,881 total hip arthroplasty patients who were on anticoagulation. The surgeries were performed between 2016 and 2023; of those patients, 4,867 were concomitantly prescribed NSAIDs and 1,040 received anticoagulation alone. Researchers concluded that the concomitant use of NSAIDs in patients on anticoagulants did not increase the risk of wound-related bleeding complications.

“The conventional thinking has often been that patients on an anticoagulant should not be on an NSAID, that there is going to be bleeding, more risk of wound problems and additional complications. But based on our retrospective data, we did not see increased risk in patients using both anticoagulation and NSAIDs. We did see some additional benefits, including less pain and a somewhat easier recovery,” Dr. Chalmers stated. “NSAIDs appear to be safe in this setting and may help decrease postoperative pain and reduce opioid use following surgery.”

The final study, “Cefazolin and the R-1 Side Chain: Why Your Joint Arthroplasty Patients With Cephalosporin Allergy Can Safely Be Given Cefazolin,” assessed the safety and effectiveness of the antibiotic Cefazolin in patients with documented cephalosporin allergies. This is the first study to evaluate these questions.

From 2016 to 2024, researchers compared patients with a reported cephalosporin allergy who received perioperative cefazolin with those who received alternative antibiotic prophylaxis. This study included 89,993 hip and knee arthroplasty patients. Of these, 1,267 had a documented allergy. The study resulted in zero incidence of IgE-mediated or “severe” type IV allergic reactions, concluding that cefazolin can be safely administered to most patients with an existing cephalosporin allergy.

“When patients have a mild allergic reaction, there is often a reflex to give them another antibiotic in a different family of drugs. However, alternative options aren’t always as effective,” said Matthew S. Austin, MD, hip and knee surgeon at HSS and a study author. “Clear protocols should be put in place to guide decision-making when managing these types of allergies.”

These findings underscore HSS’s ongoing commitment to challenging conventional assumptions and using data-driven research to refine perioperative care. The studies highlight how targeted medication strategies can improve safety, reduce complications and enhance outcomes for patients undergoing hip and knee arthroplasty.

Study Details 

“Aspirin Versus Potent VTE Chemoprophylaxis in Total Knee Arthroplasty: Reduced Postoperative Pain and Complications with Aspirin Use”

 Alex Anatone, Alexis Gabriel Gonzalez, Richard Hwang, David Andrew Kolin, Aaron Ira Weinblatt, Amar S Ranawat, Alejandro Gonzalez Della Valle, Brian Chalmers

“The Effect of Concomitant Use of Potent Anticoagulation and Anti-Inflammatories on Early Outcomes of Total Hip Arthroplasty”

Alexis Gabriel Gonzalez, Aaron Ira Weinblatt, Agnes Cororaton Jones, Stephen Lyman, Richard Hwang, Alex Anatone, Carlo Marega, Alejandro Gonzalez Della Valle, Brian Chalmers

“Cefazolin and the R-1 Side Chain: Why Your Joint Arthroplasty Patients With Cephalosporin Allergy Can Safely Be Given Cefazolin”

Josef Jolissaint, Katherine E Mallett, Andrew Thomson, Alberto V Carli, Matthew Austin

Read the full article at healio.com.

“I’m very proud of our team for publishing this work, which validates hip arthroscopy as a longer-term joint-preserving procedure in carefully selected patients,” says Bryan T. Kelly, MD, MBA, President and CEO of HSS and a world-renowned pioneer in the field of hip arthroscopy who also served as senior author on the study. “At HSS, we focus on providing excellence in clinical care through innovation and evidence-based research. This paper is a prime example of the benefits of advancing innovations in surgical techniques and analyzing patient data collected over many years so we can understand and share the factors associated with optimal results.”

Hip impingement, also called femoroacetabular impingement (FAI), is a condition that typically arises between the teenage years and middle age, and is the underlying cause of hip pain in about 40% of patients in this age range. Hip impingement occurs when the bones of the hip joint are not shaped properly, causing them to rub against one another. Over time, the persistent friction can lead to pain and stiffness, eventually progressing to advanced arthritis. 

Prior studies have shown that 85-90% of patients with hip impingement who undergo modern arthroscopy return to their usual activity level. However, until now, little has been known about whether modern arthroscopy can slow the progression of arthritis in these patients. To explore this connection, investigators examined X-ray images of 200 hips from 100 patients who exhibited signs of impingement in both hips but only underwent arthroscopy for their symptomatic hip between 2010 and 2012. The severity of arthritis in each hip was assessed retrospectively using X-ray images taken before surgery and at least 10 years later. Notably, the researchers were unaware of which hips had undergone surgical correction during the assessment.

The resulting analysis revealed only 28% of operative hips showed an increase in arthritis progression at a minimum of 10 years after surgery in comparison to 48% of nonoperative hips. This difference translated to a relative risk reduction of 42% across all patients. 

While there was no difference in the natural development of arthritis between the operative and nonoperative hips for 70% of patients, one in four, or 25%, had less arthritis in their operative hip compared to their nonoperative hip 10 years later.

“Previous studies by other centers have reported underwhelming 10-year arthroplasty outcomes for patients with hip impingement. However, those studies reported on older surgical indications and older surgical techniques,” explains lead author and former HSS fellow Prem N. Ramkumar, MD, MBA, now an orthopedic surgeon at Long Beach Lakewood Orthopedic Institute, in Long Beach, California. “By contrast, we studied the effect of modern arthroscopic methods by comparing the degree of arthritis in each patient’s operative hip versus their nonoperative hip. Our research design controlled for variables such as age, medical history, lifestyle, and individual mechanics like rotational profile, spinal alignment and gait—leaving history of arthroscopy as the single factor driving any resulting differences in arthritis progression.”

In addition, the investigators identified a small subset of patients whose arthritis progressed more rapidly in the operative hip as compared to the nonoperative hip. Specifically, older age, a higher arthritis grade, an alpha angle greater than 65 degrees and evidence of borderline hip dysplasia before surgery were the primary risk factors associated with the 5% of hip impingement patients whose arthritis in the operative hip worsened more quickly after surgery.

“We can now identify patients most likely to benefit from arthroscopy for hip impingement and inform patients about their anticipated odds of successful outcomes based on their personal risk factors. For ideal candidates, the evidence shows that hip arthroscopy may delay or prevent arthritis for one in four patients. That’s very powerful information,” says Danyal H. Nawabi, MD, FRCS, an HSS orthopedic surgeon and an author on the study.

Dr. Nawabi also points to the importance of the modern techniques used to care for patients in the study, all of whom were patients of Dr. Kelly. These methods include labrum repair, removal of bony abnormalities on the ball and socket, and proper closure of the joint capsule enveloping the hip joint. “This study is a testament to the fact that where you go for orthopedic care truly matters,” he adds.

Thus far, the paper has garnered two awards: the 2024 American Orthopedic Society for Sports Medicine Fellow Research Award for Clinical Science, which will be presented at the AOSSM Annual Meeting in July, as well as the Philip D. Wilson, MD, Award, presented by HSS in honor of the hospital’s fifth Surgeon-in-Chief to a fellow who has demonstrated excellence in orthopedic surgery research.

Research highlights include the evaluation of artificial intelligence (AI) chatbots to provide accurate answers to medical questions about spine surgery, and two retrospective studies analyzing outcomes in both knee and hip replacement surgeries performed with robotic assistance. 

HSS Research Evaluates Whether AI Chatbots Provide Reliable Medical Information

A study co-authored by Sheeraz Qureshi, MD, MBA, co-chief of HSS Spine and colleagues identified nine frequently asked questions about cervical spine surgery, which they considered to be of particular clinical relevance. Question topics ranged from the benefits and drawbacks of different surgical approaches to side effects and recovery after surgery. The questions were inputted one at a time into ChatGPT version 3.5. Two experts in cervical spine surgery who were not involved in designing the questions rated the chatbot’s responses on accuracy, appropriateness, and readability. On average, the responses received a score of 8.1/10, with a 3.9/5 for accuracy and a 2.2/3 for appropriateness. The main drawback the reviewers noted was that ChatGPT failed to provide comprehensive responses, often omitting important factors. AI chatbots are more accurate than expected when asked to answer medical questions about spine surgery, however patients still need to use extreme caution when turning to these tools for help with medical decision-making.

New HSS Studies Highlight the Benefits of Robotic-Assisted Joint Replacement Surgery

HSS investigators presented two retrospective studies analyzing outcomes in both knee and hip replacement surgeries performed with robotic assistance.

The first study co-authored by HSS hip and knee surgeon Seth A. Jerabek, MD, and colleagues found that the use of a surgical robot during total knee replacement surgery reduced the need for manipulation under anesthesia, an outpatient procedure that may be prescribed when physical therapy after surgery becomes too painful for the patient due to joint stiffness caused by scar tissue.

The second study led by HSS hip and knee surgeon Elizabeth B.  Gausden, MD, MPH and colleagues compared short-term outcomes (e.g., rates of dislocation, re-operation, revision, and patient-reported outcome measures) of the anterior versus the posterior approach in robotic-assisted total hip replacement surgery. The investigators found that hip replacement has excellent outcomes with each respective approach when performed by surgeons with extensive experience in that approach. Additionally, it is likely that the very low incidence of instability or dislocation overall can be attributed to the use of robotic technology for planning and execution.

Treatments for a femoral neck fracture range from nonoperative management to total hip replacement. When hip replacement is the best treatment option, it can be performed with or without bone cement to secure the prosthesis.

“Femoral neck fractures are very common in the elderly and are a major cause of morbidity and mortality in this population,” explained Alexander McLawhorn, MD, a hip and knee orthopedic surgeon at HSS and study author. “Several national registry studies have demonstrated a lower risk of overall revision surgery, and specifically revision for periprosthetic fracture, with cemented femoral fixation. Despite this overwhelming data, many patients in the United States receive cementless fixation, including patients who have sustained femoral neck fractures.”

“To our knowledge, this was the first non-registry study comparing outcomes of cemented versus cementless total hip replacement for acute femoral neck fractures examining the influence of various patient factors, including bone quality,” explained Michael Kheir, MD, who presented the study at the AAOS meeting and played a leading role in the research during his fellowship at HSS. “The primary purpose was to compare complication rates between both groups, including periprosthetic fractures, aseptic revision, dislocation and mortality rates.” Dr. Kheir is currently an orthopedic surgeon specializing in hip and knee replacement at the University of Michigan.

The retrospective study analyzed 709 total hip replacement cases (199 cemented, 510 cementless) for femoral neck fractures from 2006 to 2020 at three large academic institutions: Hospital for Special Surgery, Indiana University Health and University Hospitals Cleveland Medical Center. Patient demographics, perioperative characteristics and x-rays were reviewed. The Dorr classification system, widely used to evaluate femoral bone quality, categorized patients with Dorr type A, B or C, with type C indicating the weakest bone. 

The average age of study participants was 71 years; 66.9% of patients were women. The prevalence of Dorr type bone was 21.1% type A; 66.3% type B; and 12.6% type C. Patients receiving cemented implants were older, had a lower BMI, were more often women and were more likely to have a pre-existing diagnosis of osteoporosis and Dorr C bone type.

Cementless implant stems had a higher all-cause aseptic femoral revision rate (5.1 versus 0.5%,) and periprosthetic femoral fracture rate (4.3 versus 0%). Bone classification played a major role: Each successive Dorr grade had a higher fracture rate with cementless implants (Dorr A =2.3%; Dorr B = 3.7%; Dorr C = 15.9%). There was no difference in rates of dislocation, revision due to infection or mortality rate between groups. The study found an equal distribution of male and female patients who sustained a fracture.

“While femoral fractures occurred in patients with all types of bone quality, Dorr C bone was particularly prone, with an alarmingly high fracture rate when using cementless stems,” Dr. Kheir noted. “All of the fractures requiring a revision surgery occurred in cementless cases, suggesting that cemented stems may minimize this complication, regardless of patient sex or Dorr classification.”

Authors: Alexander McLawhorn, MD, MBA; Emile-Victor Kuyl, BS, (HSS); George Ochenjele, MD, FAAOS, (UH Cleveland Medical Center); Jacob Speybroeck, MD; Julian Dilley, MD, (Indiana University Health); Michael M. Kheir, MD, (University of Michigan); R M. Meneghini, MD, FAAOS, (Indiana University Health Phys)

Hip arthroscopy is one of the fastest growing orthopedic procedures in the United States, and despite being minimally invasive, it is a painful procedure for which analgesia can be difficult to manage. 

“Hip arthroscopy is becoming a more popular procedure performed at free standing ambulatory surgery centers (ASC). It is important to provide optimal analgesia to help combat against the over reliance on opioids for pain relief and also to facilitate discharge and patient satisfaction,” said Dr. David Kim, anesthesiologist at HSS.

A review of the literature for opioid-sparing options has not revealed a clearly superior regimen for managing pain after this surgery. 

Because ultrasound has become more common to perform nerve blocks, novel motor-sparing blocks have been introduced, such as the PENG and LFCN. When performed separately, these blocks have been shown to provide suboptimal pain relief or to cause quadriceps weakness, if a high volume of injectate spreads to the femoral nerve. Case studies have been written on combining these nerve blocks, but this is the first prospective randomized controlled trial conducted to validate this finding.

Investigators identified 1,559 patients who had elective hip arthroscopy at HSS between January 2019 to December 2020. Of that group, 268 received both a neuraxial anesthetic and a peripheral nerve block; 86 received a PENG and an LFCN block; and 26 received a PENG block, only. A control group of 112 patients received no blocks. 

The primary outcome was total opioid consumption in the PACU. Secondary outcomes included average numeric rating scale (NRS) pain scores, maximum NRS pain scores, length of PACU stay, incidence of postoperative nausea and vomiting, and admissions to the hospital for pain management. 

Patients who received both a PENG and LFCN block required significantly less opioids in the PACU (15 mg [15,15] vs 22.5 mg [15 34]). They were also discharged earlier than the control group (2.4 hours [1.8,3.4] versus 4.1 [3.5,4.9]); 2.72 hours versus 4.42 hours, p <0.001). The combined PENG/LFCN group also used less intravenous rescue opioids than the control group (0 mg [0,0] versus 0 mg [0,2], p = 0.0099), and the highest NRS pain scores showed a significant difference in the PENG/LFCN group vs control group (7 [5,8] versus 7 [6,8], p = 0.0437). The group who received the PENG block alone did not show a significant difference in opioid reduction, but was discharged from the PACU earlier than the control group (3.35 hours [2.7,4.3]versus 4.9 hours [3.8,5.7], p = 0.0023).

These results demonstrate the combined PENG and LFCN block could be an opioid-sparing method of pain relief after hip arthroscopy. “PENG combined with a lateral femoral cutaneous nerve block decreased opioid consumption, and facilitated expedient discharges,” Dr. Kim noted.

Dr. Kim concluded “Follow up research should include a prospective randomized controlled trial comparing PENG, PENG with lateral femoral cutaneous nerve block, and no blocks, with primary focus on analgesia and motor strength.”

Reference

1. David H Kim MD, Genewoo Hong MD, JD, Edward Lin MD, Sang Jo Kim MD, Jonathan Beathe MD, Douglas Wetmore MD, Stavros Memtsoudis MD PhD MBA, Jiabin Liu MD PhD. “Pericapsular Nerve Group block combined with a lateral femoral cutaneous nerve block decreases opioid consumption after hip arthroscopy: a retrospective cohort study.” Presented at: 47th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), March 31-April 2, 2021; Las Vegas, NV.

 Three studies focus on how to optimize total knee arthroplasty (TKA) surgery using biomechanics and computer modeling, while another study discusses how three-dimensional (3-D) modeling can improve total hip arthroplasty (THA).

 What follows are some highlights from the meeting:

Undersizing Tibial Baseplates in Cementless TKA Has Negative but Small Impact for Bone–Implant Interaction: A Computational Biomechanical Study

Computational biomechanical modeling is useful for taking a closer look at how making changes to orthopedic surgery techniques affects patient outcomes. A study led by Fernando J. Quevedo-González, PhD, assistant scientist in the Department of Biomechanics at HSS, and HSS hip and knee surgeon Jonathan M. Vigdorchik, MD, used these kinds of models to determine how best to minimize the risk of complications in cementless TKA. The model was developed using preoperative scans from 12 female patients about to undergo robotic TKA and was used to ask questions about how sizing the tibial baseplate (the metal part of the prosthesis that connects to the shin bone) affects outcomes. The investigators found that, in general, decreasing the size of the baseplate increased the amount of bone at risk of failure, but this risk was small compared with normal variability of bone quality among patients and how their individual knee joints were loaded as they used their knee in performing activities of daily living. Based on this result, they concluded that baseplate undersizing can be done to optimize the placement of the tibial component of the TKA without increasing the risk of bone failure.

Authors: Fernando J. Quevedo-González, PhD, Peter K. Sculco, MD, Cynthia Kahlenberg, MD, Joseph D. Lipman, MS, Timothy M. Wright, PhD, Jonathan M. Vigdorchik, MD.

Posterior Tibial Slope in Total Knee Arthroplasty: The Transmalleolar Sagittal Axis Underestimates Slope Compared to Traditional Intramedullary Axis

The tibial slope, one of multiple angles used to place a TKA, defines how the tibial component meets the knee and impacts the knee’s ability to bend and the strain that’s put on the ligaments throughout range of motion. A study led by HSS hip and knee surgeons Brian P. Chalmers, MD, and Steven B. Haas, MD, looked at how robotics and computer navigation influence the tibial slope in TKA. Historically, knee implants were designed using what is called the intramedullary axis to measure the tibial slope, but technology-assisted knee replacement operations determine the slope in a different way. The investigators retrospectively reviewed preoperative CT scans from 40 TKA procedures and reconstructed the 3-D geometry of the tibia and fibula to determine the slope based on the intramedullary axis. They determined that in many cases, the alternate calculation of the slope used in technology-assisted procedures resulted in a different slope in the newly implanted knee. This difference could have a negative effect on the knee’s movement and mechanics, suggesting that as more procedures are performed using robotic-assisted technology, the need to re-think implant designs to incorporate these changes is likely.

Authors: Brian P. Chalmers, MD, Fernando J. Quevedo-González, PhD, Michael P. Ast, MD, Steven B. Haas, MD.

The Initial Fixation of Cementless TKA Is Associated with the AP Translation During Gait: A Computational Study

The two main goals of TKA surgery are restoring the motion of the knee joint to as close to a native knee as possible, and ensuring that the implant is properly attached to the bone so that it lasts as long as possible and does not loosen. A novel study led by Jonathan Glenday, PhD, a postdoctoral fellow, and Fernando J. Quevedo-González, PhD, assistant scientist, both in the Department of Biomechanics at HSS, looked at the intricate relationship between attachment to the bone and joint motion, and how these two aspects of joint mechanics are related. The investigators used a computational model that included gait mechanics and anatomic information from CT scans to look at whether the anterior-posterior (AP) translation (front-to-back movement) of the femur with respect to the tibia while walking was correlated with bone-implant micromotion after surgery. Based on their models, they determined that the AP translation significantly related to the peak micromotion throughout gait, especially in the lateral portion of the knee; greater AP translation resulted in larger micromotions. This study highlights the connection between joint-level mechanics and fixation-level mechanics in TKA surgery and is the first time researchers at HSS have been able to look at both in tandem.

Authors: Jonathan Glenday, PhD, Peter K. Sculco, MD, Jonathan M. Vigdorchik, MD, Joseph D. Lipman, MS, Cynthia Kahlenberg, MD, David J. Mayman, MD, Timothy M. Wright, PhD,  Fernando J. Quevedo-González, PhD.

Three-Dimensional Functional Impingement in Total Hip Arthroplasty: A Biomechanical Analysis

Impingement after THA can lead to pain and, in the worst case, a dislocation of the prosthesis. Offset of components, which is related to the width of the hip, directly affects the impingement of the hip after surgery. Surgeons have multiple ways to alter offset during THA surgery; however, these alterations have only been studied in two dimensions. A team led by HSS hip and knee surgeon Jonathan M. Vigdorchik, MD, and former clinical fellow Eytan Debbi, MD, PhD, used 3-D models created from pre- and postoperative CT scans of 16 patients who underwent the procedure to retrospectively analyze the relationship between offset and impingement. They compared cup/liner (acetabular) offset to head/stem (femoral) offsets and looked at the effects that these configurations had on the patient’s range of motion and incidence of impingement after surgery. The investigators found that in all cases, increasing the offset reduced the amount of impingement, and increased the full range of motion of the hip. Acetabular offsets had greater impact than femoral offsets in the range of motion because they affect the offset of the center-of-rotation.

Authors: Eytan Debbi, MD, PhD (Cedars-Sinai), Fernando J. Quevedo-González, PhD, Seth A. Jerabek, MD, Timothy M. Wright, PhD, Jonathan M. Vigdorchik, MD.

Between 2000 and 2016, the number of total hip arthroplasty (THA) procedures performed in patients under 21 years of age increased from 347 to 551, while the total pediatric population in the United States remained stable, the researchers found.

Traditionally, most young patients undergoing THA suffer from developmental bone or joint ailments or juvenile inflammatory arthritis. However, the new study revealed that the upswing in THA procedures in young patients is not being driven by a rise in the number of children with inflammatory joint disease, suggesting that nonsurgical therapies to control these conditions are working, said Bella Mehta, MBBS, MS, MD, a rheumatologist at HSS and the senior author of the study.

“Our study shows that although THA procedures are increasingly being performed in young people, we aren’t seeing more of these patients seeking surgery for inflammatory arthritis,” Dr. Mehta said. “We’re doing a better job at treating these individuals so they don’t develop end-stage joint damage. Twenty years ago, we didn’t have access to effective pharmacologic treatments for these conditions, and now we’re using them well and helping these patients live a better life.”

“These procedures are still pretty rare in hospitals, and some surgeons might not see any young patients,” added Alex Gibbons, a research assistant in Dr. Mehta’s group and a co-author of the study. “Although some site-specific data on THAs in adolescents exist, it wasn’t known how frequently these procedures were being performed in the United States and if that frequency was growing or not.”

For the study, Dr. Mehta and her colleagues used the Kids’ Inpatient Database, a repository of information on patients under 21 years of age from approximately 4,200 hospitals in 46 states. The researchers looked for elective and non-elective primary THA procedures.

The mean age of young patients undergoing THA was just over 17 years and remained constant throughout the duration of the study. Most patients were white (55.3%) and had private insurance (56.5%). The majority (80%) of THAs were performed in urban teaching hospitals.

Mark P. Figgie, MD, chief emeritus of the Surgical Arthritis Service at HSS and a co-author of the study, said the finding that most THA procedures in young patients are performed in urban and teaching hospitals reflects a trend that is beneficial for these patients. As other studies have demonstrated in conditions like inflammatory arthritis, when hip replacements are performed by surgeons with significant experience, patients have better outcomes. “And for younger patients, the nuances require the expertise and knowledge to avoid complications and optimize outcomes,” Dr. Figgie said.

The most common diagnoses for young patients undergoing THA were osteonecrosis, osteoarthritis and juvenile idiopathic arthritis (JIA)/inflammatory arthritis, the researchers found. Over the course of the study, the frequency of THA for osteonecrosis rose from 24% to 38%, while that for arthritis fell from 27% to 4%—likely a reflection of recent improvements in medical management for the condition, they added.

Dr. Figgie noted that improvements in implant technology and materials have made the devices far more durable than they were 20 years ago. As a result, surgeons now feel more comfortable offering THA to young patients because their implants are likely to withstand the wear and tear of decades of activity.

Dr. Mehta said the findings could be of value both to clinicians and young patients, for whom, in many cases, the surgery is their first major operation. “I would use these results to say to a young person: ‘There are a lot of people who get these procedures; you’re not alone.’ I find that, especially for young patients, knowing they’re not the only ones to experience something really helps. And it’s a life-changing procedure for them.”

That’s the conclusion of a new study by researchers at Hospital for Special Surgery (HSS), in New York City, who assessed the clinical and financial effects of such initiatives for its patients undergoing hip and knee replacement surgery. Between 2014 and 2019, implementation at HSS of so-called bundled payment programs for the two procedures saved the Centers for Medicare & Medicaid Services (CMS) nearly $24 million while reducing readmissions and the utilization by patients of costly but at times medically unnecessary postoperative treatments such as intensive rehabilitation.

“Under the BPCI [Bundled Payments for Care Improvement Initiative] and CJR [Comprehensive Care for Joint Replacement] bundle programs, we were able to provide high-quality care efficiently, which in turn led to good outcomes for patients and cost savings for the payer,” said Catherine MacLean, MD, PhD, Chief Value Medical Officer at the HSS Center for the Advancement of Value in Musculoskeletal Care, and the lead author of the study.

The results were published by Dr. MacLean and other HSS colleagues in an article titled “The clinical, operational and financial components of a successful bundled payment program for lower extremity total joint replacement,” which appears in the October issue of NEJM Catalyst Innovations in Care Delivery.

In bundled payment programs, CMS provides a lump sum to physicians and/or hospitals to perform certain procedures, in this case, knee and hip replacement surgery. Doctors and hospitals that provide care at a cost lower than the target amount can keep the savings -- so long as certain quality standards are met. However, if the cost is higher, the hospitals must cover the amount above the target price.

The goal of these programs is to push health care providers to develop innovations and efficiencies that save money while preserving, or even improving, the quality of care. Savings can be used by the hospital to develop and deliver additional services that are aimed at improving quality and achieving the best use of health care resources.

As the results reported in the new study suggest, bundled payment programs can work well. However, Dr. MacLean said the success of the bundled care program at HSS -- and other medical centers that hope to achieve similar results -- hinges on access to the kind of granular data about patient outcomes that CMS provides HSS and other facilities that participate in the agency’s CJR payment model. Under the CJR, HSS is able to track the use of services and Medicare expenditures for individual patients once they leave the hospital, matching them with the hospital’s electronic medical records system. “These data allow us to better understand what happens to our patients once they are discharged and why some are readmitted,” Dr. MacLean said.

One example of an enhancement in care that was enabled by access to granular CJR data involved the identification of a significant number of hip and knee replacement patients who had excessively long stays in skilled nursing facilities after their operations. “It didn’t make sense that patients who walked into a hospital for an elective procedure were staying in a nursing home for 26 days,” Dr. MacLean said.

HSS responded to that information by implementing a health optimization program to identify and tailor care to patients with conditions known to lead to worse postoperative outcomes -- such as uncontrolled diabetes and malnutrition. HSS surgeons placed greater emphasis on pre-surgery physical therapy to ensure patients are as fit as possible prior to their operations. In addition, the hospital created clear pathways to help clinicians determine the optimal form of rehabilitation for patients upon discharge.

Although the CJR specifically covers knee and hip replacement patients, Dr. MacLean said the lessons learned from the data have led to wide-ranging benefits. “The programs that we have put in place as a result of our analysis of CJR data have had a spillover effect on how we manage our entire population. As a proof point, our Medicare spending per beneficiary improved from the 62^nd to the 16^th percentile nationally during the study period,” she said.

Dr. MacLean’s group is now working on an analysis of the effectiveness and efficiencies of HSS@Home, a telemedicine physical therapy program launched in 2018, before the COVID-19 pandemic.

More than one million Americans undergo knee, hip, elbow and shoulder replacements annually. About one in 75 patients, less than two percent, develop bacterial infections around the joint implants, called prosthetic joint infections. Though the numbers of affected patients are small, the consequences of prosthetic joint infection can be severe.

HSS performs more joint replacement surgeries than any other hospital in the world—a total of 11,000 annually. “Our infection rate is significantly below the national average, but prosthetic joint infections are devastating for affected patients,” says Mathias P. Bostrom, MD, chief of the Adult Reconstruction and Joint Replacement Service at HSS. “Many do not return to the full potential of their original joint replacement.”

It is essential to identify the bacteria causing an infection so that a patient receives the right antibiotic. Since current blood tests only report levels of inflammatory markers, such as C-reactive protein and erythrocyte sedimentation rate, surgeons typically collect a fluid sample from the joint via needle aspiration. However, standard lab test results take at least three days and fail to identify the infectious pathogen in 15 to 20 percent of cases due to the challenges of growing bacteria in culture.

When bacterial identification is unknown, surgeons withhold antibiotics until they obtain tissue samples during the implant removal surgery. The removal procedure involves taking out the contaminated implant hardware and infected soft tissue. Surgeons insert a temporary spacer containing high-dose antibiotics, and they may also place antibiotic beads into the joint. Patients are also treated with high-dose intravenous antibiotics. It takes about six weeks to three months for an infection to clear before patients can undergo another operation to remove the spacer and receive a new permanent joint implant.

The idea for finding a new way to improve the diagnostic approach for patients with prosthetic joint infections began with principal investigator Laura Donlin, PhD, co-director of the Derfner Foundation Precision Medicine Laboratory and a member of the arthritis and tissue degeneration program of the HSS Research Institute. She attended a talk by a professor of bioengineering at Stanford University who had analyzed DNA shed from transplanted organs circulating in blood, called cell-free DNA, as an early detection system for transplant rejection. But through genomic sequencing of circulating cell-free DNA, he had also found increased levels of viral cell-free DNA in some patients’ blood indicating they had developed viral infections while taking immunosuppressant medications.

Dr. Donlin wondered if it would be possible to use the same approach to identify bacteria in patients with prosthetic joint infections. “It was unknown whether bacterial DNA from localized tissue infections around joint implants would be detectable in blood,” says Dr. Donlin. “It’s a challenging environment with many other bits of circulating microbial DNA from skin flora, the gut microbiome and other infections.”

For their proof-of-concept study, Dr. Donlin together with orthopedic surgeons including Michael P. Cross, MD and Dr. Bostrom and colleagues at HSS and Weill Cornell Medicine collected blood samples from 53 patients with known hip or knee prosthetic joint infections beginning in 2018. Karius, a genomic insights company based in Redwood City, California, sequenced blood samples collected from patients before treatment for infection and at the time of reimplantation surgery. They compared microbial cell-free DNA in the blood samples to their proprietary database of more than 1,300 known microbial genomes. The HSS investigators compared sequencing findings with results from standard tissue cultures.

Among surgical tissue samples from these 53 patients, traditional lab cultures identified the bacterial species in 35 cases and the bacterial genus in 11 cases, an overall detection rate of 87 percent. Microbial cell-free DNA sequencing identified the bacterial species in 23 cases in agreement with standard culture results. The new approach also identified the bacterial species in eight cases where cultures identified the bacterial genus only and four cases where cultures failed to determine the presence of bacteria.

On its own, microbial cell-free DNA sequencing pinpointed the bacterial species in 66 percent of samples. However, as an addition to standard culture results, it increased pathogen detection from 87 to 94 percent of samples. Microbial cell-free DNA sequencing was three days faster reporting the bacterial species for cases where culture results had only identified the bacterial family.

Analyses of follow-up blood samples after joint removal surgery and treatment with antibiotics showed undetectable or reduced bacteria levels. “For most patients, we saw microbial cell-free DNA levels drop below detection, indicating the infections had most likely cleared,” says Dr. Donlin. “But there were some cases with lower yet detectable levels after six weeks of antibiotic treatment. Considering that cell-free DNA lives in the bloodstream for only a few minutes, that meant these patients still had an ongoing infection and might require modification to their antibiotic treatment plan.”

“An indication that there is an infection, at least to the genus level for samples that fail to show results in standard cultures, will be beneficial for diagnosing and treating patients earlier for improved outcomes,” says Dr. Bostrom. “As a monitoring tool, microbial cell-free DNA sequencing has the potential to provide important information on the right time to change or stop antibiotics and for reimplantation surgery.”

Dr. Donlin and colleagues are improving the sensitivity and specificity of the new diagnostic method in collaboration with Karius and planning a multicenter study to test it on a larger scale. “In the future, we hope microbial cell-free DNA sequencing will prove to be a useful tool for detecting joint infections more quickly than is currently possible,” Dr. Donlin says. “We’re very excited that our innovation may one day translate to improved outcomes for patients.”

The study was supported by funding provided by the Price Family Foundation, the Stavros Niarchos Foundation Complex Joint Reconstruction Center at HSS, the Feldstein Medical Foundation, the Carson Family Charitable Trust, the Ambrose Monell Foundation, the HSS Research Institute’s David Z. Rosensweig Center for Genomics Research, the National Institutes of Health, the Bill and Melinda Gates Foundation, the Leukemia & Lymphoma Society and the National Science Foundation.

Previously available information suggests that oral, IV and topical TXA are all effective at reducing blood loss and drastically reducing blood transfusion rates during and after surgery, but research with direct comparisons for each method is limited.

“TXA in orthopedic surgery has become the standard of care. However, the most efficient, efficacious and cost effective method of administration remains unknown,” said principal investigator Stavros Memtsoudis, MD, PhD, MBA, an anesthesiologist at HSS. “The oral administration of TXA is logistically easier, thus reducing the risk of drug errors in the OR. It is also less costly. We are performing this study to identify if oral TXA is also equally efficacious at preventing blood loss. If this is the case, oral administration of the drug preoperatively as a one-time dose could become the standard of care.”

Dr. Memtsoudis and colleagues randomized 199 patients between ages 18 and 80 undergoing total hip or total knee replacement to receive either oral TXA (1950 mg) two hours before surgery or IV TXA (1 g) at the start of the procedure. The primary outcomes observed were blood loss and transfusion rates.

In patients who underwent total hip replacement, the estimated blood loss calculated in the post anesthesia care unit (PACU) for oral TXA was 534 ± 285 mL, versus 676 ± 550 for IV TXA. On postoperative day one, estimated blood loss was 769 ± 257 mL for oral TXA and 798 ± 302 ml for IV TXA.

In patients who underwent total knee replacement, estimated blood loss in the PACU was 289 ± 219 mL for oral TXA, and was 486 ± 670 mL for IV TXA. On postoperative day one, estimated blood loss was 716 ± 288 mL for oral TXA versus 846 ± 659 mL for IV TXA.

No patients received transfusions during surgery. One patient who received IV TXA received a transfusion after surgery.

“Given our interim results, it seems that the oral version of TXA is equally as effective as intravenous administration. This translates to improvements in efficiency, cost and safety, all of which are important for patients, clinicians and policy makers,” Dr. Memstoudis said. “The research seems rather clear at this point. However, a uniform translation into policy is what is needed, as there seems to be limited translation of best evidence into practice.”

Complete results of this study will be analyzed later this year.

Reference

1. Julia F. Reichel, BA, Marko Popovic, BS, Danya DeMeo, BS, Carrie Freeman, BS, Marisa Wong, BA, Haoyan Zhong, MPA, Jiabin Liu, MD, PhD, Stephen C. Haskins, MD, David H. Kim, MD, Kethy M. Jules-Elysee, MD, Meghan A. Kirksey, MD, PhD, Ellen M. Soffin, MD, PhD, Daniel B. Maalouf, MD, MPH, Sean Garvin, MD, Jonathan C. Beathe, MD, Kathryn DelPizzo, MD, Alexandra Sideris, PhD, Stavros G. Memtsoudis, MD, PhD, MBA. “The Effect of Oral Versus Intravenous Tranexamic Acid on Perioperative Blood Loss in Joint Arthroplasty Patients.” Presented at: 46th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), May 13-15, 2021; Orlando, FL.

“Patients who are not taught about opioids and pain management may have difficulty with pain control and worse functional outcomes after total joint replacement,” explained principal investigator Bradley Lee, MD, an anesthesiologist at HSS.

While research has shown benefits to educating patients about opioids, little is known about what patients understand about pain management prior to surgery.

Dr. Lee and colleagues interviewed patients via a 15-minute phone call to learn about their perceptions of pain management and opioid use. Eligible patients included those between ages 18 and 80 undergoing total hip replacement who are English-speaking with a reading comprehension above the eighth grade level. Survey questions were written by Dr. Lee in collaboration with members of the HSS Controlled Substances Task Force, an interdisciplinary committee focused on evidence-based opioid prescribing. Patients were instructed to answer the questions to the best of their ability, and if unsure to respond “I don’t know.”

Responses to the interviews revealed that while many patients acknowledge experiencing some pain after surgery is normal and that opioids should be used to reduce pain that limits function, many also believed that the goal of opioid use should be to experience minimal or no pain after surgery, reflecting somewhat inconsistent expectations.

Many patients were aware of the potential risk of addiction from opioid use. However, many did not understand the role of multimodal analgesia—that multiple forms of pain relief should be used in combination to better relieve pain, and that use of non-steroidal anti-inflammatory drugs (NSAIDs) can improve pain after surgery and reduce opioid use.

There were also gaps in patient understanding of opioid use and disposal. While many recognized the importance of keeping opioids away from children, only 15% recognized the importance of locking up these medications. The researchers also found that about half of patients were unsure of how to properly dispose of opioids.

These results show potential areas of patient education that could improve patient expectations and satisfaction, pain relief, and safety. “Patients may benefit from clinicians providing a consistent message on pain expectations and the goal of using opioids after surgery to treat pain. Patients may also benefit from education about the role of multimodal analgesia, as well as proper methods of storage and disposal,” Dr. Lee noted.

“Future research should focus on educational interventions that address gaps in patients' understanding of opioids and pain management. Research should seek to identify which interventions are effective and how they affect outcomes,” he concluded.

Reference

1. Bradley H. Lee, MD, Ryan Goydos, MS, Ejiro Gbaje, MPH, Alexandra Sideris, PhD, Christopher L. Wu, MD. “Evaluating Patient Perceptions of Pain Management and Opioid Use Prior to Hip Arthroplasty.” Presented at: 46th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), May 13-15, 2021; Orlando, FL.

HSS Researchers Find Duloxetine May Reduce Opioid Use and Improve Pain Management After Total Knee Replacement

• Anesthesiologist Jacques Ya Deau, MD, PhD and colleagues investigated using duloxetine after surgery to reduce pain and opioid use. They found that duloxetine, given on the day of surgery and once daily for 14 days afterwards, reduced opioid use by about 30%. Patients receiving duloxetine were also more satisfied with their pain management.

Study Identifies Risk Factors for Pediatric Opioid Dependence After Surgery

• Anesthesiologist Kathryn (Kate) DelPizzo, MD and colleagues identified risk factors for persistent opioid use after surgery in pediatric patients. Understanding risk factors for opioid dependence could help develop strategies to prevent long-term opioid use in this vulnerable population.

Knowledge Gaps on Opioid Use and Pain Relief After Surgery Offer Opportunities for Improving Patient Education

• Anesthesiologist Bradley Lee, MD and colleagues identified gaps in patient knowledge about pain management and opioid use before total hip replacement, including misconceptions about how much pain relief to expect from opioids after surgery, how to use multiple modes of pain relief, and proper opioid storage and disposal. Improving patient education about opioids and pain management could lead to improvements in pain control and functional outcomes after surgery.

Interim Study Results Suggest Oral Tranexamic Acid (TXA) Is Equally Effective as Intravenous TXA in Preventing Blood Loss in Joint Replacement Surgery

• Anesthesiologist Stavros Memstoudis, MD, PhD, MBA and colleagues examined the efficacy and safety of oral TXA for joint replacement surgery. Using oral TXA versus intravenous TXA could translate to improvements in efficiency, cost and safety.

HSS Study Examines Hip Fracture Patient Characteristics and Outcomes Pre- and Post-COVID-19 Outbreak

• Anesthesiologist Stavros Memstoudis, MD, PhD, MBA and colleagues sought to compare characteristics and outcomes of hip fracture patients admitted during the COVID-19 outbreak to patients admitted before the outbreak. They also examined characteristics and outcomes of hip fracture patients with and without the virus.

Dr. Roche is a board-certified orthopedic surgeon and pioneer of complex knee reconstruction, including robotic and sensor-assisted partial and total knee joint replacements. He has performed thousands of minimally invasive reconstructive joint procedures, and works extensively with professional, amateur and recreational athletes, served as a Consultant Team Physician for the Miami Marlins, and is a member of the American and European Knee Society. Dr. Roche joins HSS Florida from Holy Cross Hospital, where he served as Director of the Robotic Joint Fellowship and has been in practice since 1996. A native of Ireland, Dr. Roche attended Cork Medical School, then completed his residency and internship at the University of Miami.

Dr. Roche is joining Dr. John L. Wang, and will lead the hip and knee joint replacement program as Director of Hip and Knee Arthroplasty at HSS Florida. The HSS Florida joint replacement program is focused on expanding HSS's expert-level care to Florida's active growing population. Dr. Wang trained at HSS in New York City and is a member of HSS Florida’s founding medical team. An award-winning orthopedic hip and knee surgeon, Dr. Wang also uses minimally invasive techniques to help patients return to their normal activities. By using computer navigation and robotic surgery, HSS surgeons are able to take a more precise and personalized approach to each patient and deliver better results. His specialties include hip replacement, knee replacement, and hip and knee reconstructive and revision surgery.

“HSS has been dedicated to advancing musculoskeletal health for 157 years, and been privileged to help thousands of Florida residents enjoy better quality of life through better quality of movement,” said Louis A. Shapiro, president and CEO of HSS. “Under the highly skilled care of Drs. Roche and Wang at the state-of-the-art HSS Florida facility, we are creating an international center of excellence for hip and knee replacements.”

“I am thrilled to be joining the talented team of physicians at HSS Florida who share in my same commitment to provide the highest standards of patient care,” Dr. Roche said. “I look forward to this new chapter and advancing the field of musculoskeletal health at the world’s leading organization for orthopedics.”

The total joint replacement program at HSS Florida comes at a pivotal time, as many Americans remain concerned about COVID-19 exposure. Given HSS’s single-specialty focus, this outpatient service provides a highly personalized, comprehensive procedure without the need to spend time in a hospital, often allowing patients to return home just hours after surgery.

For a seamless experience from beginning to end, patients meet with their team of medical experts ahead of surgery — including preoperative anesthesiology classes and a preoperative physical therapy session — and are paired with a care coordinator who serves as their point of contact throughout the patient’s journey.

For more information on HSS Florida, its total joint replacement program, or to schedule appointments with Dr. Roche or Dr. Wang, please visit www.hss.edu/florida or call 561-657-4600.