Mechanically or Kinematically Aligned Total Knee Prosthesis

Condition(s) studied

Investigational drug(s) / intervention(s)

kinematic knee prosthesis: Patients with a kinematically aligned total knee prosthesis and having a post-operative follow-up consultation within at least 1 year after their surgery are consecutively pre-selected according to the eligibility criteria.

biomechanic knee prosthesis: A group of patients with a mechanically aligned TKA and scheduled for a follow-up consultation 1 year after surgery will be identified to be matched on the aforementioned criteria (sex, age, BMI).

Study summary

The mechanical alignment technique (Mechanical Alignment - MA) of a total knee prosthesis (TKA) was developed with the aim of making the installation of a TKA simple and reproducible, and that the prosthetic biomechanics are acceptable, thus promoting good longevity of implants. This is a technique that does not aim to restore the constitutional anatomy of the knee; bone cuts are systematically made at fixed angles, in the 3 planes of space, in relation to the mechanical axes of the long bones (femur and tibia). This non-personalized implantation technique therefore systematically alters the anatomy, laxity and kinematics of the knee, causing up to 50% of residual symptoms after prosthetic implantation and 20% of dissatisfied patients.

In order to improve the clinical results of TKA, a new, more personalized and physiological technique was developed in 2007, called Kinematic Alignment (KA). This technique aims to restore the pre-arthritic anatomy, unique to each knee. Patients with severe constitutional deformity of the lower limb therefore retain this deformity after kinematic prosthetic replacement. The impact of the alignment technique on the biomechanics of the prosthetic knee remains poorly described. The main objective of this study is therefore to compare knee biomechanics between mechanical TKA and kinematic TKA.

Eligibility

Primary outcome measure(s)

• Biomechanical parameters of knee : spatiotemporal parameters — One year after surgery
  When walking on flat ground and when going up/down stairs: walking speed
• Biomechanical parameters of knee : Kinematic parameters in the 3 planes of space — One year after surgery
  dynamic hip-knee-ankle angles during the knee flexion/extension test with and without support
• Biomechanical parameters of knee : joint moments — One year after surgery
  Unit : Newton meter
• Biomechanical parameters of knee : force — One year after surgery
  Unit : body weight
• Biomechanical parameters of knee : lever arms — One year after surgery
• Symmetry index between the operated limb and the healthy controlateral limb — One year after surgery
  Comparison between the two limbs

Trial sites (1)

More Clinique du Sport, Bordeaux Mérignac trials in France

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