Functionally Aligned vs Mechanical Axis Aligned Total Knee Arthroplasty

Sponsor
Perth Hip and Knee
Study ID
NCT04748510
Status
Completed

Conditions

Eligibility Criteria

Sex
ALL
Age
45 Years - 75 Years
Healthy Volunteers
Not accepted

Interventions

  • Functionally Aligned Total Knee Arthroplasty — PROCEDURE
    Femoral + tibial osteotomy planned for equal resection of femoral condyles to replicate patient anatomy. In coronal plane, distal femoral resection of 6.5mm subchondral bone from medial + lateral condyles, adjusted 1-3mm for compensation of wear. Proximal tibia, 7mm resection from subchondral bone from medial + lateral tibial plateau. Sagittal plane, resection angle determined intraoperatively to closely match native femoral flexion + tibial slope. Axial plane: posterior femoral resection 6.5mm from the subchondral bone of medial and lateral posterior condyles. Tibial rotation aligned to Akagi's line. Adjustments will be made to bony alignment to balance soft tissues within boundaries of 6° varus/3° valgus HKA alignment. Femoral component alignment limited to 6° valgus/3° varus in coronal plane. Tibial alignment limited 6° varus/3° valgus in coronal plane. Combined flexion of components limited to 10° flexion. Soft tissue release if balance within boundaries not achieved.
  • Mechanically Aligned Total Knee Arthroplasty — PROCEDURE
    Tibial and femoral osteotomies in the coronal plane will be planned perpendicular to the tibial and femoral mechanical axes respectively to achieve neutral overall alignment. Soft tissue balance will be assessed and minor adjustments to bony alignment made to balance the knees with a maximal adjustment of two degrees valgus and two degrees varus of coronal alignment from neutral. Femoral rotation will be planned to surgical epicondylar axis and adjustments to rotation made to allow equal flexion and extension balance (to within 1mm). If balance can not be achieved within these boundaries then soft tissue release will be undertaken. In the sagittal plane, 0-3° degrees of posterior tibial slope and 0-5° of femoral component flexion will be used to optimise implant sizing whilst preventing notching. In the axial plane, the tibial component aligned to Akagi's line, which connects the medial border of the patellar tendon attachment to the middle of the posterior cruciate ligament.

Study Details

The objective of this study is to compare clinical and radiological outcomes in robotic-arm assisted TKA using mechanical alignment (MA TKA) versus robotic-arm assisted TKA with functional alignment (FA TKA). These outcomes will be used to determine if patient recovery is better with functionally aligned Mako robotic-assisted total knee arthroplasty (FA TKA) or mechanically aligned Mako robotic-assisted total knee arthroplasty (MA TKA).

Key Dates

Start date
Apr 30, 2021
Status verified
Jul 2025
Primary completion
Oct 8, 2024
Completion
Nov 14, 2024

Study Design

Enrollment
100 participants (actual)
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT

Arms

  • Active Comparator: Functionally aligned Total Knee Arthroplasty
    Knee arthroplasty performed using a functional alignment theory
  • Active Comparator: Mechanical axis aligned Total Knee Arthroplasty
    Knee arthroplasty performed using a mechanical alignment theory

Primary Outcome Measure

Change in Forgotten Joint Score After 2 Years From Baseline [ Time Frame: Preoperatively and 2 years postoperatively ]

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