Cannulated Screws are not different from other Orthopedic Implants Screws in appearance, but has a through hole in the screw core, which is convenient for the guide pin to pass through and ensure the accuracy of the screw position.
cannulated screw partially-threaded
cannulated screw locking screw
7.3mm cannulated screw partially-threaded
However,under the same size,the strength of hollow screw is weaker than that of solid screw.All cannulated screws adopt self-drilling/self-tapping screw head design,which can shorten the operation time and simplify the operation.It has deep cancellous bone thread design,and anti-cutting thread design for anti-slip and screw removal,and its self-tapping groove is conducive to embedding the screw head.Cannulated double head compression screw,using cannulated double head thread compression,countersunk head,low profile,self-tapping design.
Advantages
1.Hollow design improves the accuracy of percutaneous implantation.
2.Variable pitch thread and taper design: the pitch changes from large to small, the speed of the head into the bone is greater than that of the tail, so that when the screw orthopedic is screwed, the bone fracture surface is pressurized.
3.Full thread design of the Bone Screw can better maintain the pressure function when subjected to periodic overloading.
4.Headless design,in the use of joint area, reduce collision and stimulation of soft tissue.
Situations
First,some deep fractures,usually must first use Kirschner wire to locate,and then use cannulated screws through Kirschner wire to fix the fracture end.Because it is possible that if the Kirschner wire is positioned,the hollow screw is used after the wire is pulled out, it is easy to cause the fracture to shift again or the direction of the screw is deviated, which affects the fixation of the fracture.
Second,femoral neck fractures are usually fixed with cannulated screws,which can appropriately promote the blood circulation at the fracture end.
Medical tips
The fracture site is fixed with cannulated screws,most commonly the ankle joint,such as the medial malleolus fracture,fracture displacement,fracture gap is large,if not operated,fracture healing after the ankle joint gap will change,resulting in traumatic arthritis. Before the cannulated screw is inserted,the guide pin should be inserted first to fix the fracture and observe the reduction of the fracture. After the cannulated screw is inserted, the fracture position will not change.There is femoral neck fracture, more common in the elderly, fracture position is good,frail,can not tolerate large surgery,can take minimally invasive treatment,into the hollow screw, small trauma, quick recovery.
