Femoral intramedullary distributed anti-rotation fixing device

Abstract

The invention discloses a femoral intramedullary distributed anti-rotation fixing device, which comprises a medullary nail fixed to the center of a femur, a screw transversely penetrates through the medullary nail, the medullary nail is hollow and comprises an obliquely-arranged top and a vertically-arranged bottom, and the diameter of the top of the medullary nail is larger than that of the bottom of the medullary nail. Through holes are formed in the side portion of the medullary nail, the screw transversely penetrates through the through holes, the through holes are designed in a distributed mode, and the through holes are obliquely formed and comprise a first through hole, a second through hole, a third through hole and a fourth through hole. Wherein the screw is an anti-rotation hollow compression screw and comprises a fixed part and an anti-rotation part, threads are arranged at the end part of the fixed part, a tail cap is arranged at the end part of the anti-rotation part, andthe anti-rotation part is hollow; furthermore, the first through hole, the second through hole, the third through hole and the fourth through hole are sequentially formed in the top of the medullary nail from top to bottom. According to the invention, the screw imbedding accuracy can be obviously improved, so that bone blocks can be stabilized, the probability of healing of fracture blocks is increased, and the probability of fracture of bones and bone nails is reduced.

Description

technical field [0001] The invention relates to the technical field of medical devices, in particular to a femoral intramedullary decentralized anti-rotation fixation device. Background technique [0002] There are many femoral neck fractures and intertrochanteric fracture patients in our country every year. The commonly used and effective internal fixation method for femoral neck fractures is hollow compression screw fixation; the currently commonly used and effective internal fixation method for intertrochanteric fractures is PFNA fixation. But there are also defects in these two fixing methods. [0003] Defects of hollow compression screw fixation: ①Through the rotation of each compression hollow screw, the thread can give longitudinal pressure to the femoral head, resulting in immediate stability between the bone fragments, but this force is static and cannot continue to exist. When the tail of the screw loosens, the force disappears immediately. ②Weak bearing capacit...

AI Technical Summary

Problems solved by technology

However, there are also defects in these two fixing methods.

[0003] Defects of hollow compression screw fixation: ①Through the rotation of each compression hollow screw, the thread can give longitudinal pressure to the femoral head, resulting in immediate stability between the bone fragments, but this force is static and cannot continue to exist. The tail of the screw loosens, and the force disappears immediately

②Weak bearing capacity of screws: When the femoral head receives weight from above, a shear force will be generated between the two fracture fragments. If this shear force is to be resisted, the hollow screw must have the anti-rotation ability in the vertical direction if it is far from the fracture line. , but unfortunately, because there is very little bone in the medullary cavity of the femoral neck, and the cortex of the proximal femur is relatively thin, it cannot provide the anti-rotation ability in the up and down direction for the hollow screw

When the femoral head bears weight from above, the hollow nail will rotate downward like the bamboo piece of the folding fan on the right, and then the fracture fragment will shift as shown below, resulting in failure of fixation

[0004] Disadvantages of PFNA: ①The helical blade can complete the anti-rotation and angular stability with one implant

Therefore, this shortcoming is unavoidable

②The spiral blade enters the femoral neck and femoral head by percussion, so this fixation has no pressurizing effect, but there is a risk of separating the bone fragments

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