Mechanism
The Bennett fracture is an oblique intraarticular metacarpal fracture dislocation, caused by an axial force directed against the partially flexed metacarpal. This type of compression along the metacarpal bone is often sustained when a person punches a hard object, such as the skull or tibia of an opponent, or a wall. It can also occur as a result of a fall onto the thumb. This is a common injury sustained from bike falls, as the thumb is generally extended while around the handle bars. It is also a common injury in car crashes, especially into fixed objects, from the driver holding the steering wheel during impact. The hand moves forward, while the steering wheel rim hyperextends the thumb. Some authors have recently made an assertion against popular belief that the APL tendon is not a deforming force on the Bennett fracture. Treatment
Though these fractures commonly appear quite subtle or even inconsequential on radiographs, they can result in severe long-term dysfunction of the hand if left untreated. In his original description of this type of fracture in 1882, Bennett stressed the need for early diagnosis and treatment in order to prevent loss of function of the thumb CMC joint, which is critical to the overall function of the hand. In the most minor cases of Bennett fracture, there may be only small avulsion fractures, relatively little joint instability, and minimal subluxation of the CMC joint (less than 1 mm).
The β band consists of transferrin, low-density lipoproteins, and complement system proteins. The γ band is where the immunoglobulins appear, which is why they are also known as gammaglobulins. The majority of paraproteins appear in this band. Types
Paraproteinemias may be categorized according to the type of monoclonal protein found in blood:
Light chains only (or Bence Jones protein). This may be associated with multiple myeloma or AL amyloidosis. Heavy chains only (also known as "heavy chain disease");
Whole immunoglobulins. If immunoglobulins tend to precipitate within blood vessels with cold, that phenomenon takes the name of cryoglobulinaemia.The three types of paraproteins may occur alone or in combination in a given individual. Note that while most heavy chains or whole immunoglobulins remain within blood vessels, light chains frequently escape and are excreted by the kidneys into urine, where they take the name of Bence Jones protein.It is also possible for paraproteins (usually whole immunoglobulins) to form polymers by aggregating with each other; this takes the name of macroglobulinemia and may lead to further complications. For example, certain macroglobulins tend to precipitate within blood vessel with cold, a phenomenon known as cryoglobulinemia. Others may make blood too viscous to flow smoothly (usually with IgM pentamer macroglobulins), a phenomenon known as  Waldenström macroglobulinemia.The most common type of paraproteinemia is monoclonal gammopathy of undetermined significance (MGUS). Another form, monoclonal gammopathy of renal significance (MGRS) results in kidney damage and chronic kidney disease due to the effects of monoclonal immunoglobulins. References
External links
Paraproteinaemia at patient.info.