Clinical Trial Total Knee Replacement Patients

Principal Investigator: William Leone, MD

Total Knee Replacement (TKR) has been a well-established and successful procedure for 50 years and has helped millions of people worldwide. More than 750,000 TKRs are performed each year in the United States and recent studies indicate that number is expected to increase more than 650 percent from 2005 through 2025.

While the vast majority of patients are very pleased with their outcome, multiple studies have revealed that 20-30 percent of individuals are not satisfied following TKR, when measured with validated patient reported outcome measures (PROM). Component malposition, malrotation, and soft tissue imbalance can result in pain, stiffness and instability and are common reasons for dissatisfaction after TKR. These conditions are often difficult to recognize at the time of surgery and difficult to correct until now.

For the last several years, I have been utilizing a new FDA approved technology, VERASENSETM by Orthosensor Inc., which incorporates microelectronics and sensors to measure real-time kinetics and intercompartmental loading during total knee arthroplasty (TKA). A computer microchip and load sensors are incorporated into trial polyethylene inserts with matching geometries of the standard original equipment manufacturer (OEM) components. These sensor trials can be placed into the tibial tray both during the “trialing phase” and after the final components are implanted for “final trialing.”

As the surgeon takes the knee through a range of motion (ROM), dynamic load measurements are generated for the lateral and medial tibial compartments. A reference location of the load in each compartment throughout the ROM can also be used to evaluate knee kinematics. Armed with this data, I can determine if compartmental loading and knee kinematics are desirable or if further resection or soft-tissue releases are indicated.

When a healthy knee flexes, the tibia rotates internally on the femur, pivoting in the medial compartment. During extension, the tibia externally rotates as it moves into full extension (screw home mechanism). The soft tissue sleeve that surrounds the knee and the cruciate ligaments within the knee help support and guide the knee as it moves through this complex motion. The most consistent and best results after TKR are in those patients whose knee movement after TKR most closely matches their natural knee movement before TKR and when soft tissue loads medially and laterally are nearly equal and physiologic. These patients are also most likely to report that their TKR feels natural and comfortable.

Over the last several years I have been using VERASENSE during revision TKR. A few colleagues and I looked at a series of revision cases retrospectively to determine if the integration of intraoperative sensing data had the potential to decrease the need for all component revision. In this review, approximately 88 percent of intended total component revisions (plan to revise both femoral and tibial component) were changed to partial revisions based on the surgeons’ interpretation of the sensor feedback. This sparing of components saved an estimated $4,990 in healthcare provider implant costs, per case. To read full article

Holy Cross Hospital will be participating in a prospective, multicenter study using VERASENSE to evaluate Revision TKR. This study will attempt to draw relationships between the soft-tissue related complications contributing to early TKA revision and the loading and positional patterns from intraoperative tibial trial sensors.

The data from the sensors may enable the surgeon to address such soft-tissue abnormalities that may otherwise be unknown during traditional total knee revision procedures. In theory, the utilization of sensors should help diagnose the potential causes attributing to soft-tissue imbalance and may lead to a decreased need for an all-component revision. Furthermore, the economic implications from converting a total revision to a partial revision could have a profound effect on the patient and healthcare provider, such as decreased rehabilitation regimes and opportunity for cost savings. Eligible revision patients who agree to participate will be followed for a period of 12 months after the revision procedure. I have outlined the patient eligibility criteria below.

If you have had a TKR and are less than satisfied with your result, you may be interested in participating in this study. If you are a physician who provides care for or knows someone who falls into the category, please consider having them call my office for an evaluation.

Study Eligibility Criteria:

Inclusion criteria

  • Patients undergoing revision unilateral total knee arthroplasty within the first five years of the index procedure
  • Include male and female subjects
  • Include subjects 18 years and older
  • Patients should present with idiopathic pain and/or instability/stiffness attributed to aseptic loosening, polyethylene wear or malrotation
  • Patients able to understand study intent, and agree to study participation
  • Patients must be previously implanted with the following cruciate-retaining (CR) or posterior-substituting (PS) total knee systems: Stryker TRIATHLON, Zimmer-Biomet VANGUARD or NEXGEN or Smith and Nephew LEGION or JOURNEY II.

Exclusion criteria

  • No prior revision surgery on operative side
  • Ligament insufficiencies, prior surgeries such as PCL reconstructions, posterolateral reconstructions, osteotomies, tibia plateau fractures
  • Culture positive aspiration indicating infection of the joint
  • ASA class > III
  • History of drug or alcohol abuse


For more information, please contact The Leone Center for Orthopedic Care at Holy Cross Hospital, please call 954-489-4575 or visit