Per funding institution

The purpose of this study is to determine if there is a difference in clinical outcomes after total knee replacement (TKR) performed with traditional ligament balancing compared to use of intraoperative sensing technology (IOS) to balance ligaments. IOS is used to send real time information to a monitor within the operating room that assists your surgeon in making decisions about the balance of the ligaments in your knee and the proper insertion of implants. A total of 150 subjects will participate in this study at Hospital for Special Surgery.

The hypotheses are that the use of IOS technology will be associated with:

1. Better soft tissue balance during TKR than by manual balancing alone.
2. Higher patient reported clinical outcome measures (PROMs) following surgery.

Participation in this study will involve a knee replacement performed with IOS. Patients will be randomized into one of two groups:The study group will have soft tissue balance performed with the use of IOS. Control group patients will have soft tissue balance performed manually, with final soft tissue balance values measured using IOS, while the surgeon will remain blinded to those values. Intra-operative compartment loads will be measured in 10, 45, and 90 degrees of flexion.

Additionally, long leg limb alignment, passive range of motion, use of opioids, daily activity, and PROMS will be evaluated post-operatively to determine which group has better outcomes.

Inclusion Criteria:

• Patients who meet the indications for use for primary TKR using IOS
• Subject must be diagnosed with osteoarthritis
• Subject is likely to be available for all study visits
• Subject is able and willing to sign the informed consent and follow study procedures

Exclusion Criteria:

• Revision total knee arthroplasty

• Patient is receiving treatment for any of the following conditions:

  1. Avascular Necrosis
  2. Inflammatory arthritis
  3. Post-traumatic arthritis

• Any knee surgery other than meniscectomy (can be arthroscopic or open)

• Ligament insufficiencies, prior surgeries such as anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) reconstructions, posterolateral reconstructions, osteotomies, tibia plateau fractures

• Ipsilateral foot/ankle and hip arthritis

• Range of motion less than 90°

• Subject has a mental condition that may interfere with the subject's ability to give an informed consent or willingness to fulfill the study requirements (i.e. severe mental retardation such that the Subject cannot understand the informed consent process, global dementia, prior strokes that interfere with the Subject's cognitive abilities, senile dementia, and Alzheimer's Disease)

• Any subjects meeting any contraindication criteria as identified in the locally approved labeling for the device should be excluded from this study.

• Patient out-of-state with medication prescription not registered in iStop database

• Patients with severe contralateral osteoarthritis requiring subsequent knee replacement or with a flexion contracture greater than 10 degrees.