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To assess knee stability, physical examination tests are most of the time applied by our medical practitioners. While these clinical maneuvers are essential, they often rely on subjective factors such as clinician experience, muscle relaxation, and inherent knee variability and do not provide any objective results on knee stability. However nowadays, thanks to Genourob's arthrometers, it is now possible to run precise assessments on knee stability.
The LDA® Method is an innovative patented technique created by the company Genourob in 2007. It is a new way of running assessments on the knee, more precisely on knee stability that is incorporated in the company's products. Precise objective data on the various knee ligaments is collected with these advanced medical devices by applying various types of movement on the tibia to recreate the physical examination tests but in an automated way. To be more explicit, Genourob's arthrometers recreate the anterior drawer test (GNRB arthrometer) and the pivot shift test (ROTAM arthrometer) but with objective precise results in the form of curves, thus giving precise information on knee stability. See right graph for example: GNRB Results.
Graph explanation: The horizontal coordinate represents the forces applied on the tibia while running an automated Lachman test with the GNRB. The femur is of course locked in position while tests are run. The vertical coordinate represents the tibial displacement subject to the force applied. Both curves represent each assessment run on each knee (Left/Right).
Red curve: Pathological Knee | Green curve: Healthy Knee |
For more details on how the GNRB works, visit the page dedicated to this arthrometer.
To easily answer this question, it is best to compare the results obtained on two different patients and explain the differences. The data that is shown below is the result of assessments that were done on two different patients using the GNRB arthrometer.
Results of two different patients
The graphs above show the GNRB's precision for giving objective results regarding knee stability. With various forces applied on the tibia, the assessments can be qualified as dynamic tests, which were proven to be more effective in the study of Bercovy and Weber. The slope of the curves being measured is the attribute of dynamic tests as it is the only technique of measuring knee stability.
So far, only measuring the differential of laxity (displacement differential) at a single applied force is what most arthrometers on the market do. Further to this, it has been proved that only studying the displacement differential (doing a static analysis) for analysing knee ligaments can sometimes lead to false diagnosis and does not give any objective result on knee stability.
Both graphs shown above undeniably prove this by comparing two different patients' results.
Patient 1: Stability in both knees | Patient 2: Instability in left knee |
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The tables chart above resumes the analysis done between on Patient 1 and 2: The only difference resides in the fact that the slopes 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 result covering knee stability and the state of the ACL.
The GNRB is therefore a unique and very advanced arthrometer (Laximetre) for evaluating knee stability and the state of the anterior cruciate ligament following knee injuries.
The GNRB arthrometer is a medical device developed by company Genourob since 2007. This tool was initially designed for the assessment of the knee stability resulting from the state of the anterior cruciate ligament (ACL). Its technology is loosely based on the anterior drawer test, more specifically on the Lachman test. The LDA® Method present at the core of this device is what distinguishes it from all other athrometers currently present on the market.
Advantages of using this arthrometer following ACL injuries:
For more info, check out our article on the advantages of using an arthrometer in your everyday practise.
Genourob's last innovation in the field of knee ligaments assessment is the ROTAM. It is the first motorized medical device dedicated to inducing controlled tibial rotation. This arthrometer (aka. laximeter) has quickly risen to fame in the orthopaedic field for studying the state and performance of the knee peripheral ligamentous structures by applying a motorized tibial rotation.
Advantages of using this arthrometer following knee injuries:
For more info, check out our article on the advantages of using an arthrometer in your everyday practise.