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Motorized tibial Rotation is perhaps Genourob's most innovating way of applying the LDA® Method. It is indeed the only company in the world which provides this type of analysis of the knee by inducing medial and lateral rotation of the tibia while maintaining the femur locked in position. This method is destined to provide data on the state and performance of the peripheral ligamentous structures of the knee.
ROTAM Arthrometer using LDA® Method
INNOVATIONS of measurement with ROTAM
Running dynamic tests on the knee peripheral ligamentous structures with devices such as the ROTAM permits medical practitioners to evaluate the state of the knee ligamentous structures during the pre-surgery phase and orient them in their surgery decision like advising them whether antero-external reinforcement surgery is needed or not. The image showing Graph 1 and the Table Chart show the results obtained by the ROTAM.
Dynamic tests allow doctors to have two valuable parameters:
- The tibia rotation differential.
- The slope of the curves of each knee.
The data collected by these two parameters are essential and make the ROTAM unique of a kind as it is the only device currently present on the market that objectively evaluates rotational laxities.
The measurement of angle variation are registered every 0.1 Nm. After each test, the data on the knee is immediately saved on the computer that is provided with the ROTAM. Selection and comparison of specific results is possible and can easily be done.
Calculation of rotation differential and slopes of the curves is automatically done.
During the past decades, in the orthopaedic field, the medical devices destined to run tests on the knee were most of the time only designed to analyze the state of the anterior cruciate ligament (ACL) using anterior tibial translation. These devices are the GNRB, the KT1000, the TELOS or the rolimeter and none of them allowed analysis of the state and performance of the peripheral ligamentous structures of the knee. Hence Genourob's ROTAM was introduced to the market.
Today, Genourob provides medical devices for the orthopaedic industry by creating products which are innovating as they have their own way of gathering results (LDA® Method integrated in our devices run dynamic tests) and in the fact we offer medical practitioners a new approach to diagnosing knee pathologies.
The LDA® Method integrated in the ROTAM indeed allows doctors to run dynamic tests on the knee (different torques applied on the tibia) enabling the results to be shown under the form of curves. Analysis consequently becomes more interesting because studying the slope of the curves in addition to the rotation differential turns out to be possible ultimately leading medical practitioners in obtaining valuable information on knee stability and on the state of ligamentous structures.
1) Positioning of the patient: The patient's leg is placed on the ROTAM so that his knee is at 45° of flexion and a knee-cup is placed over the patella of his knee. This cup is than tightened so that the patella is pushed against the femur therefore preventing them from any kind of movement. During the process, the foot is locked in position so that the patient has no way of doing any vertical movement with his leg. Likewise to the GNRB, a sensor is to be placed on the anterior tibial tuberosity but it is not a displacement sensor but rather an inclinometer sensor. This sensor is placed in order to collect precise data on the rotation of the tibia when the torque is applied.
2) Testing: The ROTAM starts applying a controlled torque on the tibia which creates a rotation movement of the tibia, the medial or lateral tibial rotation. While applying this movement, the sensor located over the anterior tibial tuberosity collects data on the rotation of the top of the tibia since the patella/femur are locked in position ultimately giving data on the state and performance of the peripheral ligamentous structures of the knee as they are put in stress.
3) Data collection: The rotational data collected is immediately saved on the computer database and easily comprehensible through torque/rotation curves.
Therefore, overall check-up of the knee ligamentous peripheral structures' state is easily and quickly done. Since the torques applied on the knee are controlled (forces applied between 3 Nm and 8 Nm), the tests can be done during the pre-surgery phase to analyze the state of the knee peripheral ligamentous structures and during the post-surgery phase to follow the state and performance of the antero-external reinforcement (if one was done).
Please find below a video showing how a test is done with the ROTAM.
The very rigorous fixation at the distal tibia level ensures a measure of the tibial rotation without parasite motion by the ankle joints.
To compare the measures, the LDA® Software posts the ligamentous prolongation curves and the differentials of rotation between the knees.
The image located on the left "Test parameters" indicates how the values should be interpreted.
ROTAM - Patient Positioning Tutorial
Medial rotation: large differentials of rotation point to an affected ACL and the anterior-lateral tibia plane (Possible choice for extra-articular surgery in relation to ACL surgery).
At lateral rotation: large differentials of rotation point to an affected ACL and the posterior-lateral tibia plane (Possible choice for extra-articular surgery in relation to ACL surgery).
Both graphs in this picture show two tests that have been done on two patients, one of whom before surgery.
Graph 2: Patient shows no sign of pathologies in the peripheral ligament structures of both of his knees.
Graph 3: Patient shows a sign of instability in the peripheral ligament structures of one of his knees (Red curve).
The test confirms the efficacy of the rotatory braking functions and the quality of the ACL reconstruction and the peripheral ligament structures.
Both graphs in this picture show two tests that have been done on two patients after surgery.
Graph 4: Patient shows no sign of instability.
Graph 5: Patient shows a rotatory differential. Close rehab should be put in place.
ROTAM using the LDA® Method
1 - Fixation of ankle and thigh.
2 - Positioning of inclinometer sensor.
3 – Automatic application of adapted torque.
4 – Synthesis, comparison and immediate calculation of measurements of both knees by LDA® Software.
If you want more information, please feel free to download the "Automated Dynamic Laximetry" document just below: