Reproduced with permission from Dr Stuart Myers at www.myhand.com.au
The Triangular Fibrocartilage (T.F.C.) is a strong ligament type structure in the wrist. It acts to stabilise the joint between the Radius and Ulna. It also acts as a spacer between the Ulna head and the wrist joint. It may cause pain when torn or can result in clicking or catching in the wrist.
It has a poor blood supply and it derives its nutrition largely from the fluid in the wrist joint. The edge of the TFC has a better blood supply ( Peripheral 10-15%). The lack of blood supply has implication for healing similar to the menisci in the knee. (“Cartilages in the knee”). A central tear does not heal when torn but a peripheral tear may heal. Many people have degenerative tears of the central portion of the TFC as they get older and yet may have no pain at all.
Ulna Length ( Ulna Variance)
On a front view of the wrist the radius and ulna are approximately the same length.
With normal gripping and leaning on the hand 80% of the force passes from the wrist bones to the radius & 20% to the ulna. Minor changes in length of the ulna variance have profound implications for these forces. Approx 2mm change in length has a 20% effect on the forces.
A long ulna can cause:
- Tear of the TFC
- Arthritis on the Lunate, Triquetrum
- Tear of the L-T ligament
- Central or Peripheral tear
- Trauma or Degenerative
- Other injuries eg fracture, nerve, ligaments
- Age, Activity Level, General Health
- Non - Dominant Hand
- Risks of Surgery
- Activity modification
- Anti-inflammatory tablets
- Trim the torn cartilage
2. Arthroscopy & Ulna shortening
3. Plate removal – required in 2/3rds of cases
- If the ulna is too long
- The bone is cut using a saw and a plate is applied to the bone with 6 - 7 screws
- Overnight stay in hospital
- Plaster for 6 – 8 weeks or until bone cut has healed
- Activity restriction for 3 + months