Prospective Functional, Gait, and Outcome Comparison Study of Medial Pivot Versus Single Radius Design for Total Knee Arthroplasty

Patients with degenerative joint disease can effectively be treated with a primary total knee replacement to reduce pain and improve function in their daily lives. Theoretically, achievement of normal knee motion using a medial pivot design in total knee replacements can be recreated in comparison to single radius designs, which could lead to an improvement in post-surgical outcomes and satisfaction with the procedure. The aim of this study is to compare two types of implant designs (medial pivot and single radius) in a total knee replacement using clinical outcomes, patient reported outcomes, and overall function assessed by a specialized gait laboratory.

This is a single center, cohort study in 100 adult subjects undergoing primary total knee arthroplasty that will receive one of the two total knee device systems.

Primary total knee replacement is an effective treatment for relieving pain and improving function for patients with degenerative joint disease. Recently, design of knee implants in a total knee replacement have received increased interest, particularly the medial pivot designs. Single-radius implants are designed to minimize instability throughout the functional range of movement. Medial pivot total knee designs theoretically recreate more normal knee motion when compared to single radius designs. Both implant designs are commonly used for total knee replacements. Outcomes of TKA are evaluated by multiple methods including implant/device survivorship, radiographic assessments, clinical examinations, and patient reported outcome measures (PROMS). Laboratory based gait analysis performed at a specialized research facility is not commonly conducted in patients with positive outcomes post-surgery as this is associated with high cost. There is currently not enough research comparing these two designs directly. Research is required to determine which design may provide better clinical outcomes and satisfaction with the procedure.

In addition to your normal standard clinical care, there will be scheduled pre-operative, operative, 6-week, 6 month, 12 month, 24 month, 36 month, and 60 month follow-up visits.

Eligibility Criteria:
Inclusion Criteria:

* Subject is male or non-pregnant female aged between 18 and 75 years of age.
* Subject is willing to provide informed consent to participate in the research study.
* Subject is indicated for a primary total knee arthroplasty (TKA) based on the approved labeling of knee implant, either a medial pivot or single radius design, specifically: MicroPort Evolution Medial-Pivot Knee System, Cruciate Retaining (CS) or Stryker Triathlon Tritanium (CS)
* Subject does not have a history of previous prosthetic replacement device on the operative knee.
* Subject is currently ambulating and does not have a condition on the contralateral limb in the opinion of the investigator that would interfere with the gait laboratory evaluations.
* Subject is willing and able to comply with the schedule of events for the study and is available to return to the clinic for all required follow-up visits.

Exclusion Criteria:

* Subject has a Body Mass Index (BMI) \>40
* Subject has a diagnosis of avascular necrosis or inflammatory arthritis.
* Subject has any mental or neuromuscular disorder that would create an unacceptable risk of prosthesis instability, prosthesis fixation failure, or complications in postoperative care.
* Subject is a prisoner
* Subject has any condition, in the opinion of the Investigator that might interfere with the evaluation of the study objectives.