Fractures Around Knee
A Fracture is defined as a break in the continuity of the bone. A Fracture can be the result of high force impact or stress, or by just a trivial injury in weak bones, such as osteoporosis, bone cancer, or osteogenesis imperfecta.
Classification:
Fractures can be classified in the following ways:
According to cause of Fracture:
Traumatic: secondary to low or high energy trauma
- Pathological: secondary to trivial trauma in a bone weakened by pathologies like osteoporosis, bone metastasis etc.
According to overlying skin condition:
- Closed Fractures: when the overlying skin is not breached.
- Open Fractures: when there is varying degree of breach of the overlying skin and soft tissue.
According to cortical involvement:
- Unicortical Fracture or incomplete Fracture: when there is break in continuity of only one cortex.
- Complete Fracture: when there is break in continuity of both cortices.
According to displacement:
- Undisplaced Fractures: they are complete Fractures without any displacement.
- Displaced Fractures: they are complete Fractures with varying degrees of displacement.
According to the direction of the Fracture line:
- Linear Fracture: A Fracture that is parallel to the bone's long axis.
- Transverse Fracture: A Fracture that is at a right angle to the bone's long axis.
- Oblique Fracture: A Fracture that is diagonal to a bone's long axis.
- Spiral Fracture: A Fracture where at least one part of the bone has been twisted.
- Comminuted Fracture: A Fracture in which the bone has broken into a number of pieces.
- Impacted Fracture: A Fracture caused when bone fragments are driven into each other.
Complications of Fractures in general:
- Blood Loss
- Compartment Syndrome
- Non-Union
- Delayed-Union
- Malunion
Natural healing of Fractures:
The natural process of healing of a Fracture, starts when the injured bone and surrounding tissues bleed to form a Fracture hematoma. The blood coagulates to form a blood clot situated between the broken fragments. Within a few days blood vessels grow into the jelly-like matrix of this blood clot. The new blood vessels bring phagocytes to the area, which gradually remove the non-viable material. The blood vessels also bring fibroblasts in the walls of these vessels and this then multiplies and produces collagen fibres. In this way the blood clot is replaced by a matrix of collagen. Collagen's rubbery consistency allows bone fragments to move only a small amount unless severe or persistent force is applied.
At this stage, some of the fibroblasts begin to lay down bone matrix (calcium hydroxyapatite) in the form of insoluble crystals. This mineralization of the collagen matrix stiffens it and transforms it into bone. In fact, bone is a mineralized collagen matrix. If the mineral is dissolved out of bone, it becomes rubbery. Healing bone callus is on an average sufficiently mineralized to show up on x-ray within 6 weeks in adults and about 4 weeks in children. This initial "woven" bone does not have the strong mechanical properties of mature bone. By a process of remodelling, the woven bone is replaced by mature "lamellar" bone. The whole process can take up to 18 months, but in adults, the strength of the healing bone is usually 80% of normal by 3 months after the injury.
Several factors can help or hinder the bone healing process. For example, any form of nicotine hinders the process of bone healing, and adequate nutrition (including calcium intake) will help the bone healing process. Weight-bearing stress on bone, after the bone has healed sufficiently to bear the weight, also builds bone strength. Although there are theoretical concerns about NSAID's slowing the rate of healing, but there is not enough evidence to warrant withholding the use of this type of analgesic in simple Fractures.