“We have found that robotic assistance leads to improved implant positioning, alignment and ligament balance, which enable us to better replicate the patient’s natural anatomy,” said David J. Mayman, MD, chief of the Adult Reconstruction and Joint Replacement Service at HSS. “With our vast registry of patient data and strong commitment to research, HSS is in a unique position to continue leading the evolution of robotic assistance in the operating room.”

The first study found that the use of a surgical robot during total knee replacement surgery reduced the need for manipulation under anesthesia (MUA), an outpatient procedure that may be prescribed when physical therapy (PT) after surgery becomes too painful for the patient due to joint stiffness caused by scar tissue. During the course of care, approximately 3.5% of knee replacement patients undergo MUA, according to Seth A. Jerabek, MD, hip and knee surgeon at HSS and co-author of this study, typically within 90 days of their surgery. After MUA, patients are typically better able to participate in PT and progress in their recovery.

Investigators at HSS set out to determine if the use of computer navigation or robotic-arm assistance during surgery reduced the need for MUA. Previous studies have shown that the use of either tool leads to a more precise knee replacement.

The HSS researchers conducted a retrospective chart review of 21,893 knee replacement surgeries performed between April 2008 and December 2022. They found that the use of the robotic arm or computer navigation led to a significant decrease in the number of patients who needed MUA after surgery (2.7% of patients with robotic-assisted surgery; 2.8% of patients whose surgery was performed with computer navigation; 3.7% of patients whose surgery was performed without either technology).

“These results highlight the potential benefits of incorporating technological advancements into knee replacement surgery, offering improved outcomes and reducing the need for additional interventions such as MUA,” Dr. Jerabek said.

The second study compared short-term outcomes of the anterior versus the posterior approach in robotic-assisted total hip replacement (THR) surgery. “There is no consensus on which approach has a lower risk of postoperative complications,” said Elizabeth B.  Gausden, MD, MPH, a hip and knee surgeon at HSS and principal investigator of the study. “This can often lead to confusion on the part of the patient as to which approach may be best for them. Our objective was to compare rates of dislocation, re-operation, revision and patient-reported outcome measures of each approach performed with robotic assistance.”

Dr. Gausden and colleagues identified 2,040 consecutive robotic-assisted THRs for osteoarthritis in the HSS patient registry between 2017 and 2020. A total of 497 hip replacements were performed using the anterior approach; 1,542 were performed with the posterior approach.

At mean follow-up of 18 months, the researchers found no difference in the rate of dislocation, re-operation or revision surgery between the two approaches. At early follow-up of six weeks, the anterior approach was associated with a somewhat faster functional recovery. By 3 months following the THA, there were no longer significant differences between patients who had different approaches. “The take-home message is that hip replacement has excellent outcomes with each respective approach when performed by surgeons with extensive experience in that approach,” Dr. Gausden said. “While the goal of the study was not to compare robotic THA to manual THA, 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.”

"As the use of robotic assistance in joint replacement surgery becomes more common, future studies should evaluate outcomes over longer periods of time,” concluded Dr. Mayman. “As a leader in the use of this technology, HSS continues to study various robotic systems to acquire the data needed to provide the evidence-based care that will benefit our patients.”  

References:

Robotic-assisted Total Knee Arthroplasty Is Associated with Decreased Manipulation under Anesthesia Compared to Manual Approach

Authors: Cale Pagan; David J. Mayman, MD; Douglas E. Padgett, MD; Jonathan M. Vigdorchik, MD; Peter K. Sculco, MD; Seth A. Jerabek, MD; Theofilos Karasavvidis, MD (HSS).

Program Number: P153 – February 14, 2024

Comparison of Short-Term Outcomes Between Direct Anterior and Posterolateral Approach in Robotic-Assisted Total Hip Arthroplasty

Authors: Nikhil Vasireddi, MHA (Case Western); Sonia Chandi, MD; Colin Neitzke; Agnes Cororaton, MS; Jason L. Blevins, MD; Jonathan M. Vigdorchik, MD; Alexander S. McLawhorn, MD, MBA; Elizabeth B. Gausden, MD, MPH (HSS).

Program Number: e076 – February 12, 2024

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.

 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.

According to the article, Dr. Jerabek and his colleagues conducted a study with 1,000 patients over the course of three years and found that patients who suffered a dislocation also had significant lumbar spine disease.

"They had less spine flexion and more hip flexion to achieve the seated position," Dr. Jerabek said.

Dr. Jerabek explained that "patients with fixed spinopelvic alignment may benefit from altered acetabular cup position, potentially more inclination and more anteversion or alternative bearing designs, such as dual mobility."

Dr. Jerabek noted that future research in this area should follow patients for a longer time.

Read the full article at healio.com [registration required]. This also appeared in the May 2018 print issue.

Findings indicated that patients who received amino acid prior to and after surgery performed better postoperatively.

"Supplementation of amino acid prior to and for the first 2 weeks after surgery is a safe and easy way to improve patient recovery after surgery. It should be considered as part of your perioperative management in total knee replacement," said Dr. Mayman, who presented the study at the annual meeting of the American Academy of Orthopaedic Surgeons (AAOS) this week.

Read the full article at healio.com [registration required].