Healing
The type of healing of a bone fracture (fracture healing) depends primarily on the type of fracture. In addition, the treatment initiated for a bone fracture also has a decisive influence on its healing. In general, the types of healing of bone fractures are divided into two classes.
In medical terminology, we speak of the so-called primary and secondary healing of bone fractures. A prerequisite for the primary healing of a bone fracture is an early initiation of treatment. In addition, primary healing is only possible if the ends of the broken bone are close together and cannot be moved against each other.
As a rule, such an initial situation can only be created by surgical measures (osteosynthesis). The great advantage of primary fracture healing is the fact that, if the fracture is successfully repositioned, no inferior bone material (so-called callus) is usually formed after healing. In this type of fracture healing, the ends of the fracture are connected by the ingrowth of bone balls or the attachment of newly formed bone tissue.
However, in primary healing in the presence of a bone fracture, it should be noted that the fresh bone substance has a lower load-bearing capacity for some time than the surrounding mature bone. The newly formed bone material is degraded by bone eating cells (osteoclasts) about eight weeks after its formation and only then is it replaced by pressure and tension resistant bone. This process is known in medicine as “remodeling”.
A bone fracture whose ends are less well adapted and/or are not surgically corrected usually heals via secondary fracture healing. In this form of fracture healing, blood seeps out of the ends of the fractures immediately after the onset of violence and is distributed in the surrounding tissue (fracture gap). As a result, a haematoma is formed.
In general, the secondary healing of a bone fracture is divided into five phases, which, however, partially overlap. Following the formation of the haematoma, the release of various substances that trigger an inflammatory reaction in the area of the fracture ends is initiated. This second phase of the secondary phase of the bone fracture (inflammatory phase) covers a period of approximately 2 to 3 days.
The blood in the area of the bone fracture begins to clot and over time is exchanged for so-called granulation tissue. In this way, a connective tissue-like scar structure is first formed around the fracture ends during the healing of the fracture. The pieces of bone are therefore initially only elastically connected to each other and thus their mobility is only limited.
In a further step in the secondary healing of the bone fracture, bone-eating cells (osteoclasts) break down the destroyed bone substance. Subsequently, cartilage-forming cells (chondroblasts) migrate and begin to synthesize firmer cartilage material (fibrocartilage). After a while, the fibrocartilage ossifies and the fracture heals permanently.
In medical terminology, this is known as the “granulation phase”. After about 3 to 4 weeks, the ends of the fracture are connected partly by cartilage and partly by bone-like substance. The disadvantage of this type of fracture healing is the fact that inferior bone (so-called “callus“) is formed as the bone ends grow together.
The stability of this bone substitute is much lower than the load-bearing capacity of ordinary bone. Furthermore, callus tissue is characterized by an irregular surface.This can lead to long-term problems, especially in the area of joints. For this reason, primary fracture healing should always be aimed for in bone sections close to joints.
However, it is now assumed that even with the secondary healing of a fracture, a kind of remodeling will begin after some time and the callus tissue will be steadily replaced by stable bone. The healing time of a bone fracture can vary greatly. Various factors are decisive for the actual healing time.
Firstly, the type of fracture plays a decisive role in the speed of fracture healing. Simple bone fractures usually heal much faster than complicated comminuted fractures. On the other hand, the region where the fracture was caused by force also has a decisive influence on the healing time.
Depending on the location of the fracture, the healing time can therefore be between two and six weeks. In addition, specific factors in the organism of individual patients can shorten or lengthen the fracture healing time. For example, a fracture of the nasal bone is usually completely healed within two weeks.
If the fracture is in the region of large tubular bones, for example the thigh, the healing period can even extend to up to twelve weeks under certain circumstances. In general, it can be observed that the healing time of a bone fracture increases significantly with age. Bone fractures can be operated on under general anesthesia.
The duration depends on the type of fracture. The operation is performed with various screws, wires and plates that hold the bone together. The complications of an operation always include bleeding, infection, injury to surrounding structures such as nerves, vessels and muscles.
Especially infections of the bone can be dangerous, because they heal only slowly and poorly. After the operation there is a certain risk of thrombosis, which should be taken into account. With or without surgery, there is also always the risk that a bone fracture will not heal properly and pseudoarthrosis will form.
If these problems occur, another operation may be necessary. Overall, however, these risks are quite rare and, if they do occur, should not cause too many problems.
