The main functions of screws include fixed connection, pressurization and position maintenance.Specifically, screws can connect the steel plate to the bone, generate pressure or friction, and thus fix the two; lag screws form pressurization between the fracture fragments through sliding holes to achieve absolute stable fixation; position screws maintain the position of the fracture fragments without generating pressurization. In addition, screws are also used for repairing joint injuries, promoting bone tissue growth, fixing fracture fragments, preventing displacement and many other purposes.
The characteristics of screws include a variety of types and designs. According to the purpose, screws can be divided into cortical bone screws and cancellous bone screws; according to the different threads, they can be divided into semi-threaded and fully threaded screws; according to the design, they can be divided into locking nails and hollow nails. The ultimate goal is to achieve effective fixation. Since the advent of locking screws, the rest of the non-locking screws are called "ordinary nails". The design features of screws also include self-drilling and self-tapping functions. For example, self-tapping screws can directly tap threads on the material, while the locking nail has threads on the nut, which can match the reverse threads of the steel plate hole to achieve the purpose of locking.
Application scenarios include fracture fixation and joint repair in orthopedic surgery. For example, fracture fixation screws are used to stabilize the fracture site and promote healing; joint screws are used to repair joint damage and restore joint function; bioactive screws have the effect of promoting bone tissue growth and are suitable for specific types of fractures. In orthopedic surgery, screws are also used to connect plates to bones and fracture fragments to achieve effective fixation and recovery.
