Clinical Trial: RSA and Clinical Comparison of Anatomical and Mechanical Alignment in Total Knee Replacement

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional

Official Title: Biomechanical and Radiostereometric Analysis of the GMK Sphere Primary Total Knee Replacement. A Randomized, Double Blind Comparison of Anatomical Versus Mechanical Alignment in Total Knee Replacement

Brief Summary: Current practice in orthopedics is to recommend TKA implantation with the femoral and tibial components perpendicular to their mechanical axis. Therefore, current surgical technique does not replicate natural knee anatomy and biomechanics. An alternative alignment method that attempts to replicate the kinematics of the knee is " kinematic alignment ". The principle behind kinematic alignment is placement of the TKA components so that the orthogonal 3-D orientation of the 3 axes that describe normal knee kinematics is restored to that of the prearthritic knee. Theoretical benefits of kinematic alignment include less ligamentous release to balance the knee intra-operatively, more rapid recovery, better range of motion (ROM), less post-operative pain, better knee biomechanics, and improved patient satisfaction. However, a major concern is that there are no mid- or long-term data on implant survivorship (absence of loosening) in TKA based on "anatomical" implantation. The investigators propose to compare the clinical results of TKA implanted with mechanical alignment (standard practice) to kinematic alignment, in a double-blind, randomized trial.

Detailed Summary:

Problem to be addressed Knee osteoarthritis is a degenerative joint disease that is very prevalent in the general population and can cause significant functional impairment. Total knee arthroplasty (TKA) is the definitive treatment of choice, but rarely accomplishes complete restoration of natural knee biomechanics. Various factors may influence post-operative function: pre-operative state of the knee, patient age, implant position, and design. The natural lower limb anatomy presents a femoral joint surface that is slightly valgus according to its mechanical axis (1-5 degrees) and a tibial joint surface that is slightly varus (1-4 degrees). This combination results in an oblique joint line orientation (1-3 degrees) and a mechanical axis passing near the centre of the knee joint (line between the centre of the femoral head and the centre of the ankle). Natural lower limb alignment helps balancing load between the internal and external knee compartments at heel strike. Current practice in orthopedics is to recommend TKA implantation with the femoral and tibial components perpendicular to their mechanical axis (0 degrees). In addition, in order to maintain ligament balance (a rectangular space) in flexion, external rotation of the femoral implant is suggested (2-5 degrees according to posterior femoral condyle surfaces). Therefore, current surgical technique does not replicate natural knee anatomy and biomechanics. An alternative alignment method that attempts to replicate the kinematics of the knee is " kinematic alignment ". The principle behind kinematic alignment is placement of the TKA components so that the orthogonal 3-D orientation of the 3 axes that describe normal knee kinematics is restored to that of the prearthritic knee. Theoretical benefits of kinematic alignment include less ligamentous release to balance the knee intra-operatively, more rapid recovery, better range of motion (ROM), less post-opera
Sponsor: Maisonneuve-Rosemont Hospital

Current Primary Outcome: Component migration measured with Radiostereophotometry [ Time Frame: 2 years ]

In the first 40 cases (20 in each group), we will compare the migration with a RSA system between anatomically- and mechanically-aligned implants at 2 years and predict the long-term survivorship of total knee prostheses inserted with these two techniques.


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Clinical scores [ Time Frame: 2 years ]
    In all randomized subject, we will compare the clinical results of anatomical and mechanical total knee alignment with self reported pain, function and stiffness questionnaire scores. Validated clinical scores will be used: WOMAC, KOOS and SF-12
  • Knee kinematics measured with the Knee KG (Emovi inc.) [ Time Frame: 2 years ]
    In all randomized cases, we will compare post operative knee kinematics with the Knee KG system (Emovi inc) between the 2 groups and identify biomechanical markers that explain subjective differences (if found with clinical scores).
  • Technical benefits [ Time Frame: 1 month ]
    In all randomized cases, we will determine if anatomical alignment offers some technical benefits (reduced intra-operative ligament balance and ligaments releases) compared to a mechanical alignment technique.
  • Rehabilitation [ Time Frame: 1 month ]
    In all cases, we will compare post-operative rehabilitation in both groups (flexion, extension, straight leg raising, walking without assistance, etc.).


Original Secondary Outcome: Same as current

Information By: Maisonneuve-Rosemont Hospital

Dates:
Date Received: September 30, 2014
Date Started: January 2015
Date Completion: January 2020
Last Updated: September 23, 2015
Last Verified: September 2015