Synonyms of Pseudarthrosis
- Wrong joint
- Nearthrosis
- Nonunion
- Scaphoid pseudarthrosis
Definition
Pseudarthrosis is the failure to heal after a fracture or degenerative bone change and the failure of the defective bone parts to grow together, resulting in the formation of a false joint.
At what point does one speak of pseudarhtrosis?
The term pseudarthrosis means “false joint” and refers to a fracture that has not completely healed. Due to the lack of healing, the two ends of the fracture do not grow together and the affected bone shows a discontinuity (interruption). Normally, it takes about four to six weeks for a broken bone to heal completely, although this period of time naturally depends greatly on the location and severity of the fracture. Fractures that still have not healed after four to six months are called pseudarthrosis.
CausesForms
The causes of pseudarthrosis are often manifold. An interplay of many factors ultimately leads to delayed healing or complete failure of the bone fracture to heal. The most common cause is a lack of blood supply to the bones, which after a fracture or trauma delays or prevents the bone ends from growing together quickly.
A second common trigger after a fracture and corresponding surgery, in which metallic material is inserted and screwed in to stabilize the bone ends, is instability. If the metal (osteosynthesis material) is either applied incorrectly or if it becomes loose again after a short time, rapid healing and coalescence of the bone is prevented – pseudarthrosis develops. If the existing bone ends are too far apart and the fracture gap cannot be bridged, this also leads to pseudarthrosis.
Another important factor in the development of pseudoarthrosis is incorrect behavior after surgery, which usually consists of putting too much strain on the affected joint too early. Unhealthy lifestyle, such as excessive alcohol consumption, smoking or poorly controlled diabetes can also contribute to the development of pseudoarthrosis. A distinction is made between different forms of pseudarthrosis: so-called atrophic pseudarthrosis completely lacks a bony reaction and thus a chance of healing.
In avascular pseudarthrosis, new bone is already formed in principle, but there is no sufficient blood supply to contribute to healing (blood deficiency in the bones). The third form, hyperreactive bone formation, leads to excessive new bone formation, which progresses rapidly but is severely limited in stability. Although the bone grows together quickly, it is not properly resilient and there is always the risk of a new bone fracture. Bones that become infected after a fracture can also develop pseudarthrosis. The reason for this process, also known as septic pseudoarthrosis, is that the pathogens that have penetrated the bone prevent the desired healing process.
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