Trial Comparing Alignment Techniques - RSA of ATTUNE Knee System

This is a multi-centre, randomized controlled trial of patients undergoing cruciate-retaining total knee arthroplasty with the Attune S+ fixed bearing TKR system. Patients will be randomized to two study groups:

1. Neutral mechanical alignment;
2. Anatomical alignment.

The principal objective of this study is to compare migration patterns between mechanical and anatomic alignment surgical techniques for the Attune S+ CR-FB knee system using model-based RSA over the first 2 post-operative years.

Secondary objectives include; comparison of 2-year migration values against published thresholds for adequate short-term fixation, comparison of functional and health status of subjects following surgery, comparison of intra-operative soft-tissue releases, incidence of complications and adverse events, and to assess several health economic parameters relating to the surgery.

• Neutral Mechanical Alignment (Procedure): Hip-knee-ankle angle of 180° ± 3°.
• Anatomical Alignment (Procedure): Restoring a patient's pre-diseased limb alignment

Primary outcomes

• Implant migration [2 years]: Measured via radiosteriometric analysis (RSA)

Secondary outcomes

• Oxford-12 knee score [Pre-operative, 6 weeks, 3 months, 6 months, 1 year, 2 years]: The Oxford Knee Score (OKS) is a patient self-administered 12-item questionnaire with each question having a Likaert-like response option. Each item is scored from 0 to 4, and the items are summated, with lower total scores indicating poorer performance. The OKS measures pain and general activities of daily living.
• Pain Catastrophizing Scale (PCS) [Pre-operative, 12 months]: The patient are asked to indicate the degree to which they have the above thoughts and feelings when they are experiencing pain. Each PCS item is rated on a 5-point scale: 0 (not at all) to 4 (all the time). The PCS total score is computed by summing responses to the 13 items. PCS total scores range from 0 - 52.
• European Quality of Life (EQ-5D-5L) [Pre-operative, 6 weeks, 3 months, 6 months, 1 year, 2 years]: Evaluate and compare the change from preoperative to 2 years between the study groups timepoints in functional outcomes assessments. The EuroQol 5D 5L questionnaire is a standardized instrument for use as a measure of generic health status - completed by the subject. The EQ5D uses a Likert scale which assesses five states (mobility, self care, usual care, pain and discomfort and anxiety and depression) at five different levels - none(0), slight(1), moderate(2), severe(3) or unable to perform(5). Levels are coded 1-5 and an index score is then generated.
• Pre-operative Patient's Knee Implant Performance (PKIP) [Pre-operative, 6 weeks, 3 months, 6 months, 1 year, 2 years]: The Pre-surgical and/or Post-surgical Patient's Knee Implant Performance (PKIP) questionnaire is a patient reported questionnaire that consists of 24 questions relating to the patient's awareness of their knee. Questions include the patient's self-confidence about the current status of their knee performance, stability, and overall satisfaction. Each question has a 5, 6 or 10 Likaert- like response option.
• 7. University of California at Los Angeles (UCLA) Activity Level scale [Pre-operative, 6 months, 1 year, 2 years]: Evaluate and compare the change in UCLA activity score compared to baseline in the study cohort. UCLA activity scores range from 1 to 10, and is a measure of activity with 10 being most active.
• Pain VAS [Preoperative, 6 Weeks, 3 Months, 6 Months, 1 Year, 2 Years]: Evaluate and compare the change from preoperative to 2 years between the study groups timepoints in patient reported satisfaction as measured using the visual analogue scale (VAS) from 0 (No pain) - 100 (Worst pain imaginable)
• Patient satisfaction: VAS [Preoperative, 3 Months, 6 Months, 1 Year, 2 Years]: Evaluate and compare the change from preoperative to 2 years between the study groups timepoints in patient reported pain severity as measured using the visual analogue scale (VAS) from 0 (Unsatisfied) - 100 (Completely satisfied)
• Patient complications [Preoperative, 6 Weeks, 3 Months, 6 Months, 1 Year, 2 Years]: Evaluate the type and frequency of the complications/adverse events.
• Hospital stay [Up to 1 week]: Number of days in hospital
• Tourniquet time [Intraoperative]: Length of time tourniquet was applied (minutes)
• Length of surgery [Intraoperative]: Length of surgery, from open to closing of incision (minutes)
• Blood loss [Intraoperative]: Amount of blood loss during the procedure (mL)
• Anesthesia type [Intraoperative]: Anesthesia methods (general, spinal, epidural, TXA)
• Peri-operative pain management [Intraoperative]: A tabulation of the pain management (Peri-Articular Injection, Femoral Nerve Block, Add. Canal Block or none) used during the procedure.
• Soft tissue release [Intraoperative]: A tabulation of the tissue released during the procedure (MCL, LCL, PCL, Posterior Capsule Release).

Sex: All, ages: 21 Years to 80 Years, accepts healthy volunteers

Inclusion Criteria:

1. Symptomatic osteoarthritis of the knee indicating primary total knee arthroplasty
2. Varus knee deformity of 0 to 10 degrees
3. Sufficient ligamentous function to warrant retention of the posterior cruciate ligament
4. Between the ages of 21 and 80 inclusive
5. Patients willing and able to comply with follow-up requirements and self-evaluations
6. Ability to give informed consent

Exclusion Criteria:

1. Active or prior infection
2. Medical condition precluding major surgery
3. Inflammatory arthropathy
4. Prior patellectomy
5. PCL deficiency
6. Major Coronal plane deformity
7. Valgus alignment
8. Bone defects requiring augments, cones and/or stemmed implants
9. Body Mass Index 45 or more

• Thomas Turgeon, Principal investigator, Concordia Joint Replacement Group