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helikopter
Dołączył: 03 Mar 2011
Posty: 735
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Skąd: England
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 Wysłany: Czw 13:43, 10 Mar 2011 Temat postu: ghd piastre fdp dso quu mfx |
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Locked intramedullary nailing dynamic design and biomechanical study
L-shaped larvae length 8nLrn, nail diameter 4nLrn,[link widoczny dla zalogowanych], the maximum sliding distance is also only 4 Ⅱ Ⅱ n, will not cause severe fracture displacement. It should be noted that when continues to load, lock screw on the top of a long exposure to L-shaped larvae, the same shear force can be formed, resulting in stress shielding. Then the two forces produced: one medullary nail and nail shear, and second,[link widoczny dla zalogowanych], the proximal tail and bone shear (anti-back nail force), the relative balance between two forces. When the shear fatigue strength than nail occurs when the nail fracture; When the shear force is less than the fatigue strength of locking screws, then nail the same time the fracture occurred further back side, the bone fragments separate pieces, limb length shortening. Tests showed that the tail has a good serrated bite force or shear pin bone, the extent of 2474.52936.2N, already has considerable stability. Therefore, the power is not the comminuted fracture of the fixed absolute taboo. 4. Tail of the anti-rotation capability: static interlocking intramedullary nail sexual capacity than any other anti-rotation within the intramedullary nail are good. In order to facilitate the surgery, I nail the top in the design of the tail, the function is anti-withdrawal and anti-rotation screw. Operation directly to the tail rotor hit the NPC, reducing the two proximal locking screws, can shorten the operation time, reduce the trauma. Torque tail test showed that: (1) tail width and anti-rotation ability. The wider the tail, the greater trochanter trabecular bone within the more the resistance, the greater the torque,[link widoczny dla zalogowanych], while the cancellous bone of the extrusion and cutting smaller. In this experiment, groups B and D wings are wide 2IILrn, its maximum torque of 10.3,11.3 Nm, has good resistance to rotation ability; Group A and Group C of the wing width are 1inlrn,[link widoczny dla zalogowanych], the largest torque only 5.3,6.2 Nm, anti-rotation capability is poor. (2) tail shape has nothing to do with the anti-rotation capability. Groups A and B are jagged tail, Group A (tooth width 1mm) of the maximum torque of 5.3Nm,[link widoczny dla zalogowanych], B (tooth width 2mm) of the maximum torque 10.3Nm, the difference was significant (P <0.05). Group C and Group D are rectangular tail, the difference also has significant (P <0.05). Therefore, I recommend the use of wing-wide, with teeth of the tail. 5. Problems to be solved: (1) remote still outside the locking nail, screw locked when not completely solve the problems; (2) because it is outside the locking nail, so still need a set of accurate sight. Solution is to design a simple structure, stable fixation, internal anti-rotation locking nail against shortening or more accurately, non-invasive sight.
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