Function, Pain, and Alignment Following Knee Replacement for the Treatment of Osteoarthritis

The registry criteria, word for word

What the trial wants to find out

There are many factors that can influence patient satisfaction and patient related outcomes following total knee replacement including the surgical alignment of the joint components. Historically, total knee replacements have been performed with an aim aiming to achieve neutral alignment or a mechanical weight axis in the lower extremity . However, only 0.1 % of the population have a pre-surgical anatomical neutral alignment, and therefore the constitutional anatomy of the patient is neglected. There is a growing trend to return patients back their anatomical constitutional alignment after a knee replacement, referred to as Kinematic Alignment using robotics. The aim of this randomized controlled trial is to examine how mechanical alignment and kinematic alignment impacts function, pain, mood and fatigue following TKR for the treatment of osteoarthritis. Outcomes will be measured at 6 week, 6 months, 1 year and 2 years after surgery.

The 3 groups in the trial

• Manual Adjusted Mechanical AlignmentExisting treatment, for comparison

  Usual care: * Midline incision, no tourniquet, medial Parapatellar arthrotomy, resect anterior osteophytes * Distal femoral cut with 3-5 degrees of valgus from the anatomical axis (Based on the angle measurement on the 4 foot standing Xray). Correct for flexion contracture. * Measure the femoral size with the anterior referencing guides. Use 3 degrees external rotation to the Posterior condylar axis * Perform anterior, posterior and chamfer cuts with the 4 in 1 in appropriate external rotation * Extramedullary tibial alignment guide with 3-5 degrees posterior slope, and orthogonal cut to the tibial axis. * Resect posterior osteophytes * Place trial components and perform appropriate release/balance the gaps * Patellar replacement based on surgeon's discretion * Cementing the components with tourniquet inflation

  Treatment: Total Knee Replacement

• Robotic Assisted Adjusted Mechanical AlignmentTreatment being tested

  * Midline incision, no tourniquet, medial Parapatellar arthrotomy, resect anterior osteophytes * Place the femoral pins in the proximal incision and the tibial pins 4 finger breadths under the joint line * Map the knee and perform evaluation * Assess gaps, adjust the femoral axis to decrease soft tissue release (+/- 2 degrees), correct for flexion contracture * Verify and perform distal femoral cut, proximal tibial cut orthogonal (90 Degrees) to the tibial axis * Assess and balance extension gap with appropriate releases * Remap the posterior condylar axis, assess the flexion space, 3 degrees external rotation to the posterior condylar axis * Perform anterior, posterior and chamber cuts with the 4 in 1 (appropriate external rotation), followed by posterior osteophyte resection * Place trial components and balance the knee, soft tissue releases (1-2 mm) * Patellar replacement based on surgeon's discretion * Cementing the components with tourniquet inflation

  Treatment: Total Knee Replacement

• Robotic Assisted Kinematic Alignment: (Joint line restoration)Treatment being tested

  \-- Midline incision, no tourniquet, medial parapatellar arthrotomy, resect anterior osteophytes * Place femoral pins in proximal incision, tibial pins 4 finger breadths under joint line * Map and evaluate the knee, ROM, varus valgus testing at 0 \& 90 degrees flexion * Distal femoral cut based on cartilage loss on medial and lateral femoral condyle (9mm total cut/condyle). * Perform distal femoral cut, maintain the joint line (femoral axis +/- 5 degrees) * Perform proximal tibial cut within +/- 3 degrees, balance the gaps, differential between medial and lateral gaps = 1- 3mm. * Assess extension space, resect posterior osteophytes * Remap posterior condylar axis, place 4 in 1 at 0 degrees to the post condylar axis (aim = 9mm posterior condylar cuts) * Resect posterior osteophytes, place trial components. Adjust cuts to achieve a balanced knee, maintain HKA axis +/- 3 degrees * Patellar replacement per surgeon discretion * Cement the components with tourniquet inflation

  Treatment: Total Knee Replacement