Osteosynthesis is defined as fixation of a bone. It is a surgical procedure to treat bone fractures in which bone fragments are joined with screws, plates, nails or wires. The fractured bone is fixed with the aforementioned and can knit stably in the correct position.
Osteosynthesis or internal bone fixation are not used to treat every type of bone fracture. Osteosynthesis is most suitable for open bone fractures with concomitant injury to the skin or soft tissue. It is also the preferred form of treatment for bone fractures with multiple fragments, bone fractures on the leg and bone fractures in patients with osteoporosis.
Different osteosynthesis methods such as screw osteosynthesis, plate osteosynthesis, intramedullary pin osteosynthesis, tension band osteosynthesis, Kirschner wire fixation, external fixation devices and dynamic hip screw are used. The materials used nowadays consist primarily of titanium.
What preparations are carried out before the procedure?
The bone fracture must be precisely imaged in an x-ray or an MRI before the operation. Based on the examination results, the doctor decides which osteosynthesis method to use.
All the usual pre-operative assessments are required, such as a blood test, blood pressure measurement and an ECG. The patient must stop taking blood-thinning medication and have an empty stomach for the procedure.
How is the operation carried out?
The location of the fracture and the type of break will have a bearing on which surgical procedure is used. Furthermore, the location of the fracture and the patient's general condition will also determine whether the surgery is carried out under general anaesthesia, spinal anaesthesia or local anaesthesia.
In the case of screw osteosynthesis, the bone fragments are fixed with screws. A hole is drilled in the broken piece in question to this end. A thread for the screw [tension screw] is drilled in the opposing fragment or a screw with a thread on the end of it is used directly [cancellous bone screw]. In both cases, the broken pieces are joined together by tightening the screws.
Plate osteosynthesis is a procedure in which the broken parts of the bone are fixed with a plate.
The surgeon exposes the broken bone and screws a suitable plate over the fracture line. This is fixed to all the fragments with screws in the bone. In the process, the broken parts are connected stably with one another.
Intramedullary nail osteosynthesis
Intramedullary pin osteosynthesis is a procedure in which the medullary cavity is opened in the broken bone. The surgeon makes a channel in the medullary cavity into which he or she can drive a nail. This nail connects the bone fragments in the manner of an internal splint. The intramedullary nail is also stabilised with a crossways bolt so that it cannot displace itself. The nail is correctly positioned with the help of x-ray imaging.
Tension band osteosynthesis
Tension band osteosynthesis is a complex procedure in which bone fragments are pressed together. Fixation wires are attached to the fragments, and they are joined together with a tension band.
Kirschner wire fixation
Kirchner wires are elastic steel wires which are used to fix breaks in small bones such as in fingers or on the collarbone. When the wires are inserted into the bone, the upper end remains outside the bone. After the fracture has healed, the wires can be removed once more. A splint or a plaster cast is also put on as the wires alone are not sufficient to stabilise the fracture.
External fixation devices
An external fixation device is an external metal support frame used to fix breaks. In the process, the surgeon makes small incisions in the skin above the breaks through which he drills holes in the bones. Metal rods are sunk into these holes and protrude from the body. The rods are fixed externally to a metal frame, thus stabilising the bone fracture externally.
Dynamic hip screw
Dynamic hip screw is a procedure to treat femoral neck fractures (thigh fractures near the hip joint). In the process, a screw is driven into the femoral head. A plate with a pipe bolted to it through which the free end of the hip screw can slide is screwed to the femur. The patient's body weight is dispersed over the hip screw in such a way that the fracture is pressed together.
What is the success rate of this procedure?
Broken bones are stabilised with the different osteosynthesis procedures until the bones have knitted once more. In general, bone fractures heal very well with this procedure.
What are the possible complications and risks of this procedure?
Osteosynthesis is one of the standard procedures used to treat fractures, and usually proceed without complications. As with all surgery, the operation may sometimes lead to infections, nerve damage, post-operative haemorrhaging or blood clots. Ankylosis, osteonecrosis or tendon adhesions may occur in rare cases, along with compartment syndrome.
What happens after the operation?
After the surgery, the patient is monitored during the recovery phase as they wake up from the anaesthesia. Physiotherapy exercises are begun soon afterwards to prevent ankylosis and to keep the muscle loss as low as possible.
The selected osteosynthesis procedure and the individual healing process will determine whether the bone can be used as normal. It takes at least six weeks for a bone fracture to heal; however, it can also take several months. However, partial mobilisation is usually possible beforehand, and the patient can put some weight on it with the help of walking aids or crutches.
Several factors determine whether the osteosynthesis material can be removed again the fracture has fully healed. The material used (titanium) can principally remain in the body your entire life. These days, the screws and plates are not usually removed unless there are specific reasons to do so.