Studies ACL: Anterior cruciate ligament
  • Anterior cruciate ligament (ACL) injury/tear
  • ACL reconstruction surgery techniques
  • Torn /injured ACL treatment
  • Torn ACL recovery time
  • Why buy a KT 1000 arthrometer when you can get a GNRB? Did I tear my ACL? TOP 5 ACL diagnostic tests KT-1000 / KT-2000 / GNRB comparison Sports related to ACL Injuries ACL fast facts Arthrometers: Enhance knee injury treatment Knee Stability/Instability Diagnostic Device Knee physical exams
  • Pivot Shift Test - Knee Instability Evaluation
  • Lachman Test - ACL assessment
  • Anterior Drawer Test - ACL assessment
  • ACL Rehab: How are arthrometers crucial to recover from ACL Surgery? New arthrometer NEW GNRB / ROTAM Research Studies GNRB Knee Arthrometer: More than just objective results on the ACL... The Future of Treating ACL Tears: Arthrometers
    The LDA® Method - Objective knee joint laxity test
  • Lachman test (automated)
  • Anterior drawer / Tibial rotation test (automated)
  • Tibial rotational instability test (automated)
  • Posterior drawer test (automated)
  • Documentations What is Laximetry? Arthrometers adapted to your speciality
  • Orthopedics
  • Sport
  • Functional Rehabilitation
  • Isokinetics
  • Radiology
  • LDA Method Scientific Studies
    Now present in more than 30 countries...
  • Chirurgie orthopedique et traumatologie du sport in Paris - France
  • Dr Ramon Cugat in Barcelona - Spain
  • Pr. Yves Tucoulou in Lanzhou - China
  • Pr. Laimonas Siupsinskas in Kaunas - Lithuania
  • Gwangju Veterans Hospital in Gwangju - South Korea
  • How we started...
    Genourob's knee laxity arthrometers REHAB
  • Accessories
  • LDA® Couch
  • LDA® Trolley
  • LDA® Biofeedback
  • ACL injury/tear assessment
  • ACL test - Medial rotation
  • PCL injury/tear assessment
  • ACL test - Adapted to x-ray technology
  • Choose your ROTAM
  • Knee ligamentous laxity assessment/test
  • Scientific Studies
    Sales in France International Sales
  • Export Sales Manager
  • Distributors in Europe
  • Distributors in Asia
  • Distributors in the Middle-East
  • Distributors in North America
    Welcome to Genourob Support GNRB SUPPORT ROTAM SUPPORT


    +33 2 43 90 43 01


    How to assess knee ligament damage: LDA® Method

    The LDA® Method is an innovative patented technique created by company Genourob destined to the assessment of knee ligamentous laxity. It provides precise evaluation of the knee ligamentous structures by applying automated and controlled tibial translation (GNRB) or rotation (ROTAM). The LDA® Method, which stands for Automated Dynamic Laximetry (Laximétrie Dynamique Automatisée in French) Method, is a new approach to the measurement of knee laxity (aka. Laximetry) that is done through dynamic tests and with results under the form of compliance curves (=opposite of stiffness curve).

    Example of a test using LDA® Method

    Graph 1

    Graph 1

    The Graph 1 shows an example of tests run on both legs of a patient using the LDA® Method while applying anterior tibial translation.

    How does LDA® Method work?

    It is quite simple: The femur is locked in position while different forces are applied on the tibia. Both curves drawn on graph 1 represent the compliance (=opposite of stiffness) of the ligament that is measured.

    Green curve: Healthy Knee

    Red curve: Pathological Knee

    The dynamic tests performed on each knee are done with a precision of 0.1 mm and offer a wide range of results such as the tibia/femur displacement differential and the slope of the curves.

    This eventually leads to making a precise diagnostic of the state of knee ligaments (displacement differential) and knee stability (slope of the curves).

    Innovation: analyzing the slopes of the laximetry curves.

    Graph 2: Patient 1 (Left Graph) and Graph 3: Patient 2 (Right Graph)

    Graph 2: Patient 1 (Left Graph) and Graph 3: Patient 2 (Right Graph)

    So far, only measuring the differential of knee laxity without consideration of the slopes of the lines does not allow a comprehensive analysis of the ligament state and this has been proven by the study of Bercovy and Weber in 1995. Ironically, this is what most arthrometers created nowadays do.

    Only studying the displacement differential (doing a static analysis) for analyzing knee ligaments can sometimes lead to false diagnosis and does not give any information on knee stability. The graph 2 undeniably proves this by comparing two different patients' results.

    Patient 1 results are represented by the graph 2 and Patient 2 results are represented by graph 3.

    Patient 1: No instability in both knees

    Patient 2: Instability in left knee

    • Displacement Differential = 1.5 mm
    • Curve slope = Parallel Curves
    • Displacement Differential = 1.5 mm
    • Curve slope = Divergent Curves

    The tables chart above resumes the analysis done between graph 2 and 3: The only difference resides in the fact that the slope of the curves do not behave alike for both patients.

    This example purely states the efficiency of running dynamics tests against static tests on the knee. Considering the slope differential between both compliance (=opposite of stiffness) curves on behalf of the displacement differential between both knees ultimately leads to a much more precise analysis of the state and performance of the ligamentous structures of the knee.

    Use of LDA® Method

    Nowadays, the LDA® Method is used in various ways to allow orthopaedic surgeons, sports doctors, radiologists and physiotherapy analyzing the state and performance of the different knee ligaments in the pre-surgery and post-surgery phase of a patient's management.

    The ligamentous structures that are analyzed using the LDA® Method include:

    • Analysis of the ACL with medial rotation consideration using an automated version of the anterior drawer test (Lachman Test) integrated in the GNRB Rotab.

    If you want more information, please also feel free to download the "Automated Dynamic Laximetry" document just below: