Mechanically or Kinematically Aligned Total Knee Prosthesis

Study Overview
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Brief Summary
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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.

Official Title
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Mechanically or Kinematically Aligned Total Knee Prosthesis: Prospective and Comparative Study of Clinical, Stereoradiographic, and Biomechanical Results

Conditions
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Osteoarthritis, Knee

Intervention / Treatment
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* Device: kinematic knee prosthesis
* Device: biomechanic knee prosthesis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient followed as part of a consultation 1 year after TKA placement Adult patient Patient affiliated to a social security system Patient informed of the study and formally included (signing of informed consent) before the first research review Exclusion Criteria: Patient with a contralateral knee prosthesis Patient with another condition (acquired pathology) of the lower limbs (e.g. severe osteoarthritis of the contralateral knee or hip/ankle) and/or of the nervous system (e.g. Parkinson's) which may significantly affect the quality of walking Pregnant patient Patient deprived of liberty by judicial or administrative decision, Adult patient subject to a legal protection measure or unable to express consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: patients with kinematic aligned knee prosthesis<br> | Device: kinematic knee prosthesis<br>* 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.<br>|
| Active Comparator: patients with biomechanic aligned knee prosthesis<br> | Device: biomechanic knee prosthesis<br>* 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).<br>|

What is the study measuring?
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Primary Outcome Measures

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

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical results : Patient-Reported Outcome Measures: Functional score (OXFORD scale) | OXFORD scale : numerical rating scale used to quantify the power or strength produced by the contraction of a muscle (0-5) ; 5 is maximal strenght | One year after surgery | 
| Clinical results : Patient-Reported Outcome Measures: joint perception score | Forgotten joint score : joint-specific questionnaire that focuses on the patients' awareness of their prosthetic joint during daily activities ; 0-100 (0 is the worst result and 100 the better result possible) | One year after surgery | 
| Clinical results : Patient-Reported Outcome Measures: pain | visual analog scale (VAS) pain (numerical scale 0-10), 0 is absence of pain and 10 the worst pain possible | One year after surgery | 
| Clinical results : Patient satisfaction | Scale from not at all satisfied to very satisfied | One year after surgery | 
| Clinical results : range of mobility of the prosthetic knee | Range of motion from hyperextension to flexion (degrees) | One year after surgery | 
| Clinical results : complication rate | Complication rate (percentage) : manipulation under anesthesia, re-operation, revision, previous pain syndrome | One year after surgery | 
| Imaging results : EOS 3D, alignement of the lower limb | measurement of the frontal alignment of the lower limb (hip-knee-ankle and hip-knee-calcaneus angles) | One year after surgery | 
| Imaging results : EOS 3D, orientation of the implants | - measurement of the orientation of the implants in the frontal (medial proximal tibial, lateral distal femoral and joint line convergence angles) and sagittal (tibial slope, flexion of the femoral component) planes | One year after surgery | 
| Imaging results : EOS 3D, distance between anterior femoral cortex and prosthetic trochlea | measurement of the distance between the anterior femoral cortex and the prosthetic trochlea | One year after surgery | 
| Imaging results : radiography, evaluation of implant fixation | evaluation of implant fixation (e.g. sealing, border, reactive line) | One year after surgery | 
| Imaging results : radiography, measurement of patellar height | measurement of patellar height (pre- and post-op Caton-Deschamps index comparison) | One year after surgery | 
| Imaging results : radiography, evaluation of the bone structure | evaluation of bone structure (e.g. osteolysis) | One year after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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total knee prosthesis, mechanical alignment, kinematic alignment, biomechanic study