the opposite theory
The trasla-rotation From the bibliographic consultations also conducted for patent examination, we also found contrary opinions to roto-translational motion of the knee. The hypothesis formulated in the works of LOUDON ET AL(1998), PUTZ (1995), TOWNSEND Ind. Inc., Patent no. EP 0361405 A (1990), TOWNSEND, JEFFREY H.,WILLIAMS ROBERT J., U.S. patent no. WO 92 15264 A (1992), indicate that in flexion-extension motion the knee proposes a roto-translational motion , that is initially a front slipping of the femur on the tibia of about 8-9 mm (for an arc of 20-25 degrees) , which is followed by a phase of rotation from 25 degrees foward. This reversal of flexion-extension dynamic of the knee has lets some perplexity that led to a more detailed analysis comparing any similarities between the articular anatomy and physiology. |
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Slip back of the meniscus
The transla-rotatory theory ,instead, tends to affirm that in the first phase of flexion 20-25 degrees the femoral condyles anteriorly slip for 8-9 mm while and in any case, the meniscus pulled by the flexor muscles, moving backward. This opposite direction of movement, would bring, without doubt to a serious conflict between condyles and meniscus which might be damaged at each cycle of movement.
Disengagement of condylar tibial eminence
In the trasla-rotation movement the initial forward translation does not combined with the "disengagement of condylar tibial eminence" which occurs after 30 degrees
because the anterior translation itself would tend to keep stuck the massive intercondylar for a wider bending portion.
The mechanical function
Thetransla-rotational theory applied to the motion functionality in deambulation and running, determines significant mechanical incompatibility
The transla-rotatory theory ,instead, tends to affirm that in the first phase of flexion 20-25 degrees the femoral condyles anteriorly slip for 8-9 mm while and in any case, the meniscus pulled by the flexor muscles, moving backward. This opposite direction of movement, would bring, without doubt to a serious conflict between condyles and meniscus which might be damaged at each cycle of movement.
Disengagement of condylar tibial eminence
In the trasla-rotation movement the initial forward translation does not combined with the "disengagement of condylar tibial eminence" which occurs after 30 degrees
because the anterior translation itself would tend to keep stuck the massive intercondylar for a wider bending portion.
The mechanical function
Thetransla-rotational theory applied to the motion functionality in deambulation and running, determines significant mechanical incompatibility
The translation phase occurs during
support in which the knee is under load and reaches a working arc of 20-25
degrees.
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The rotation phase occurs from 25 to
135 degrees and in the discharge phase during the aircraft recovery in the call of the foot toward the front.
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It seems appropriate to recall that:
during the translation the two articular surfaces slide between them causing friction and usury which is proportional to the weight
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during rolling, contact between the two surfaces is always performed on contiguous points avoiding any phenomenon of rubbing and / or usury
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In consideration that biological evolution has always married the concepts of efficiency and conservation, you can hardly believe that essential activities to humans as deambulation and running can cause friction and usury in a fundamental joint to social life and the existence itself of man, such as the knee.
This suggests that the transla-rotational theory is not consistent with this concepts because usury phenomena would tend to affect the correct utilization of the joint in a very short time.
The strange thing is that the scientific work that would tend to validate the transla-rotational theory ( Putz, 1995; Loudon et al, 1998) comes after the date in which patent was born (Patent n. EP 0 361 405 A 1990, Patent n. WO 92 15264 A 1992) and which claims paternity.
This suggests that the transla-rotational theory is not consistent with this concepts because usury phenomena would tend to affect the correct utilization of the joint in a very short time.
The strange thing is that the scientific work that would tend to validate the transla-rotational theory ( Putz, 1995; Loudon et al, 1998) comes after the date in which patent was born (Patent n. EP 0 361 405 A 1990, Patent n. WO 92 15264 A 1992) and which claims paternity.