Conventional vs. Sensor Guided Soft Tissue Balancing in TKA RCT

Study Overview
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Brief Summary
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To ensure a successful outcome after total knee replacement (TKR) soft tissue balance and proper implant position are very important during the surgical procedure. Soft tissues are structures in the knee including ligaments, muscles, tendons, and menisci that stabilize and cushion the knee joint. Lack of proper soft tissue balance or imprecise implant positioning may result in knee stiffness, pain, instability and limited range of motion (ROM). This may result in implant failure and the need for revision surgery. As part of standard practice orthopedic surgeons use a manual knee balancer device to help guide soft tissue balancing to achieve optimal knee balance. New sensor-assisted technology can provide surgeons with measurable information to help achieve soft tissue balancing, providing surgeons with immediate visual feedback during the surgery. This feedback, transmitted wirelessly by the sensor, gives surgeons electronic information on soft tissue balance and implant position.The purpose of this study is to determine if a sensor guided soft tissue balancing device (Verasense) is more effective at balancing the knee during surgery as compared to standard soft tissue balancing performed with a manual balancer device.

Detailed Description
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The study is that of a prospective double-blind randomized controlled trial of patients presenting for elective primary TKR to compare the outcomes of TKR using conventional soft tissue balancing with a tensiometer device versus augmenting the soft tissue balancing with the OrthoSensor VerasenseTM sensor device. The primary outcome will be rate of unbalanced TKRs based on the quantitative Verasense definition of a well balanced knee defined as a mediolateral intercompartmental loading difference of ≤15 pounds through ROM. Secondary outcomes include differences in clinical outcome scores and patient satisfaction among sensor guided cases and controls. Patients will be randomized to receive TKR with the Triathlon total knee system (Stryker) in the case and control group according to: (1) control group with standard balancing techniques used and sensor data obtained in blinded fashion and not used to balance the TKR implant, (2) experimental case group with sensor guided balancing where sensor data is used to balance the TKR within defined parameters.

Official Title
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Randomized Controlled Trial of Sensor Guided Knee Balancing Compared to Standard Balancing Technique in Total Knee Arthroplasty

Conditions
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Total Knee Arthroplasty

Intervention / Treatment
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* Procedure: Sensor Guided Soft Tissue Balancing
* Procedure: Standard Soft Tissue Balancing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients scheduled to undergo elective primary unilateral TKR for a diagnosis of osteoarthritis to be performed at the study site by the primary investigators Willingness and ability to give informed consent. Exclusion Criteria: Inflammatory arthropathy Ligament insufficiencies Contraindications to posterior cruciate retaining TKR including: deformity >15 degrees or fixed-flexion contracture >15 degrees Previous high tibial osteotomy Scheduled to undergo sequential bilateral TKR under one anesthetic Scheduled to undergo revision TKR surgery Neuromuscular disorder limiting mobility or ability to comply with physiotherapy Previous recurrent deep knee infection Major bone loss requiring structural bone graft or augmented components Functionally limiting peripheral vascular disease Patients receiving associated worker's compensation benefits (WSIB) Ethanol/drug abuse/psychiatric disorder Inability or unwillingness to give written informed consent to participate

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard Soft Tissue Balancing<br>In the control group where the sensor device is not used in optimization of knee balance and alignment, definitive implants will be cemented in place and the sensor trial inserted using a thickness based on prior standard bearing insert trialing. Peak load data will be captured intraoperatively through full ROM. Custom shims will be affixed to the sensor to replicate thickness of the standard trial. The knee will then be cycled and loads recorded in the medial and lateral compartments at 10, 45 and 90 degrees of flexion. The surgeon will be blinded to the sensor output and the system will be located outside of their visual field. | Procedure: Standard Soft Tissue Balancing<br>* Primary TKR with soft tissue balancing with a standard of care manual tensiometer device.<br>* Other names: Triathlon (Stryker, Mahwah, NJ);|
| Experimental: Sensor Guided Soft Tissue Balancing<br>In the experimental group where the sensor device is used to optimize balance and alignment, the sensor trial will be inserted and tibial baseplate rotated until medial and lateral femoral contact points are parallel on the sensor output. Quantitative balance is defined as a mediolateral intercompartmental loading difference of ≤15 pounds. Flexion balance is achieved when femoral contact point position is within the midposterior third of the tibial insert and intercompartmental loads are balanced. Loads in the medial and lateral compartments are recorded at 10, 45 and 90 degrees. If compartment loads differ by >15 lbs between compartments, unbalanced, further soft tissue release/bone resection will be done to achieve a side to side compartment pressure difference of <15 lbs through ROM. | Procedure: Sensor Guided Soft Tissue Balancing<br>* Primary TKR with soft tissue balancing with a sensor guided device.<br>* Other names: Verasense (OrthoSensor Inc., Dania Beach, FL);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of Unbalanced TKRs | The rate of unbalanced TKRs will be assessed based on the Verasense sensor device quantitative definition of a well balanced knee. A well balanced knee is defined as having a mediolateral intercompartmental loading difference of ≤15 pounds through ROM [Gustke et al., Walker et al]. | Intraoperative at end of procedure prior to wound closure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee Society Score | Overall clinical function as measured by Knee Society Score | Preoperative, 6 weeks, 6 months and 1 year postoperative | 
| Oxford Knee Score | Subjective function as measured by Oxford Knee Score patient report outcome measure | Preoperative, 6 weeks, 6 months and 1 year postoperative | 
| Patient satisfaction | Patient satisfaction with total knee replacement; likert scale | 1 year postoperative | 
| Clinical knee function: varus/valgus alignment | Assessment of clinical knee function | Preoperative, intraoperative, 6 weeks, 6 months and 1 year postoperative | 
| Clinical knee function: anteroposterior stability | Assessment of clinical knee function | Preoperative, intraoperative, 6 weeks, 6 months and 1 year postoperative | 
| Clinical knee function: extension lag | Assessment of clinical knee function | Preoperative, intraoperative, 6 weeks, 6 months and 1 year postoperative | 
| Clinical knee function: anatomic alignment | Assessment of clinical knee function | Preoperative, intraoperative, 6 weeks, 6 months and 1 year postoperative | 
| Clinical knee function: knee ROM | Assessment of clinical knee function | Preoperative, intraoperative, 6 weeks, 6 months and 1 year postoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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knee soft tissue balancing, sensor-guided, range of motion