The triangular fibrocartilage complex stabilizes the wrist at the distal radioulnar joint. The complex sits between the ulna and two carpal bones (the lunate and the triquetrum). It stabilises the distal radioulnar and acts as a focal point for force transmitted across the wrist to the ulnar side.
Mechanism of injury
Traumatic injury or a fall onto an outstretched hand is the most common mechanism of injury. The hand is usually in a pronated or palm down position. Tearing or rupture of the TFCC occurs when there is enough force through the ulnar side of the hyperextended wrist to overcome the tensile strength of this structure.
High-demand athletes such as tennis players or gymnasts (including children and teens) are at greatest risk for TFCC injuries. TFCC injuries in children and adolescents occur more often after an ulnar styloid fracture that doesn’t heal.
Power drill injuries can also cause triangular fibrocartilage complex rupture when the drill binds and the wrist rotates instead of the drill bit. Triangular fibrocartilage complex (TFCC) tears can also occur with degenerative changes. Repetitive pronation (palm down position) and gripping with load or force through the wrist are risk factors for tissue degeneration. Degenerative changes in the TFCC structure also increase in frequency and severity as we get older. Thinning soft tissue structures can result in a TFCC tear with minor force or minimal trauma.
Anatomical risk factors
There may be some anatomical risk factors. Studies show that patients with a torn TFCC often have ulnar variance and a greater forward curve in the ulnar bone. Ulnar variance means the ulna is longer than the radius because of congenital (present at birth) shortening of the radius bone in the forearm.
Wrist pain along the ulnar side is the main symptom. Some patients report diffuse pain. This means the pain is throughout the entire wrist area. It can’t be pinpointed to one area. The pain is made worse by any activity or position that requires forearm rotation and movement in the ulnar direction. This includes simple activities like turning a doorknob or key in the door, using a can opener, or lifting a heavy pan or gallon of milk with one hand.
Other symptoms include swelling; clicking, snapping, or crackling called crepitus; and weakness. Some patients report a feeling of instability.
The classification that is used to describe the injuries are Palmer Class 1 for traumatic injuries and Palmer class 2 is used to label or describe degenerative conditions. Each class is subdivided.
Diagnosis can be made based on clinical examination and investigations that may help can include x rays but more helpful is an MRI arthrogram.
Treatment can be conservative if there is no instability in which case a splint or cast may be used for a period of immobilisation. surgery options undertaken includes an arthoscopy with a view of debridement of central lesions and repair of peripheral lesions
The outcome of surgery is influenced by the type of lesion and the management that has been undertaken
Minami et al reviewed 16 patients (average age, 30 y) with a follow-up of 35 months. Palmer class 1 tears were found in 11 patients, and Palmer class 2 tears were found in 5 patients. Of the 16 patients, 13 returned to their previous jobs. Palmer class 1 tears were associated with excellent results; and Palmer class 2 tears were associated with poorer results
Trumble et al reviewed 24 patients after arthroscopic repair of Palmer classes IB, IC, and ID tears. The average patient age was 31 years. Treatment occurred within 4 months after injury, with a follow-up of 34 months. Postoperative range of motion was 89%, and grip strength was 85%. Thirteen of 19 patients returned to their original jobs or sports. Follow-up studies demonstrated that the triangular fibrocartilage complex (TFCC) was intact in 12 of 15 patients.