The specific structures most often torn in TFCC tears are the meniscal homologue and articular disc (2). This is usually caused by forced or over extension (hyperextension) and pronation of the wrist which is the position most often assumed when falling onto an outstretched arm (3,4, 6). Forces that pull the wrist away from the ulna (distraction forces) can also tear the TFCC (7). This type of injury is more often seen in tennis players and baseballers because of the great distraction forces felt by the wrist when the bat/racquet contacts the ball. TFCC injuries are also common amongst gymnasts whose wrists often move into these extreme positions. Tears to the TFCC can also occur with fractures of the radius or ulna (22), as indicated in Palmer’s classification of TFCC tears (below).
TFCC tears do not always occur as a result of a trauma and may occur as a result of degenerative changes in the wrist. A degenerative tear may occur as a result of ‘ulnocarpal impaction syndrome’ – when the end of the ulnar chronically ‘impacts’ on the TFCC and the 2 wrist bones it connects with (lunate and triquetrum). This often occurs as a result of ulnar variance (when the ulnar is longer than the radius). Ulnar variance can occur as a congenital defect (defect from birth) or as a result of trauma, which may, for example, hinder growth of the radius. Ultimately these conditions lead to increased wear and subsequently degeneration of the TFCC. However, degenerative changes in the wrist do not always need a specific trigger to occur and may result as a natural progression in the ageing process (22).
Palmer (1989) classified TFCC tears into 2 classes according to their mechanism of injury. Class 1 tears are those that occur as a result of a trauma, while Class 2 tears are those that are a result of degenerative changes in the wrist. The subtypes are further classified according to the severity and/or location of the tear.
Class 1 : Traumatic cause
A : central perforation (tear)
B : ulnar avulsion with or without distal ulnar fracture
C : distal avulsion
D : radial avulsion with or without sigmoid notch fracture
Class 2 : Degenerative cause
A : TFCC wear
B : TFCC wear with lunate and/or ulnar chondromalacia
C : TFCC perforation with lunate and/or ulnar chondromalacia
D : TFCC perforation with lunate and/or ulnar chondromalacia and LT ligament perforation
E : TFCC perforation with lunate and/or ulnar chondromalacia, LT ligament perforation, and ulnocarpal arthritis
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My friend recently was in a accident while skiing. His doctor told him he had torn his shoulder, and hand muscles from the fall. He had told me that he had only separated his shoulder from the fall but it turned out to be much worse. When I saw his shoulder earlier today, it was a good 1/4 of an inch lower than the other side. We're not sure what is going to happen but your article helped me to get my own opinion.
ReplyDeleteLuke | http://www.orthoclinic.com.au/shoulders.html