The ankle is made up of the tibia and fibula bones of the lower leg, and the tarsus bone of the foot. They are held together by ligaments, which provide strength and stability during movement.
The tibia and the fibula are held together by the syndesmosis joint, a special joint that allows very little motion between the bones, but provides strong stability to the ankle joint. Ligaments that connect the tibia and fibula include:
- Anterior inferior tibio-fibular ligament: present in front of the two bones
- Posterior inferior tibio-fibular ligament: present behind the two bones
- Transverse ligament: crosses over the back of the bones
- Interosseous ligament: present between the two bones
Any twisting or rotational injury, especially forceful upward and outward movements of the foot, can injure the syndesmosis ligaments causing stretching or tearing of the ligaments.
Syndesmosis injuries, also called high-ankle sprains, are commonly seen in high-level football players and snow skiers. It is a severe type of foot and ankle sprain causing pain, swelling and weakness. In some cases, the tibia and fibula may draw apart (diastasis) resulting in ankle instability. This type of injury often requires Syndesmosis surgery with TightRope fixation to restore the stability and function of the ankle.
Syndesmosis surgery is indicated in cases of diastasis causing instability or when conservative treatment measures do not help relieve ankle pain and weakness. Conservative measures include pain and anti-inflammatory medications, rest, ice, compression, elevation and ankle bracing.
Syndesmosis with TightRope fixation may be performed to avoid complications associated with screw fixation (insertion of screws to hold the tibia and the fibula together).
Surgery is performed under general anesthesia usually on an outpatient basis but may require an overnight stay.
- Your Surgeon makes an incision over the outer side of the ankle joint and removes any impeding structures such as scar tissue keeping the tibia and fibular apart.
- Your surgeon attaches a fixation plate on the fibula and inserts screws through it.
- Once the fibula has been stabilized, its alignment with the tibia can be restored with the TightRope fixation.
- The TightRope is made up of a polyethylene cord secured between two metallic buttons (one oblong and one round button).
- Using a guide wire, a hole is drilled through one of the holes of the fixation plate across the fibula and tibia.
- The oblong button, threaded to the TightRope cord, is passed through this tunnel with the help of a needle and pulled back so that it lies flat against the tibia. The wires connected to the needle are cut.
- Your surgeon pulls the cord, pulling the round button against the fixation plate on the fibula and tightening the system. The ends are tied and trimmed.
- If more stability is required a second hole may be drilled to insert another TightRope.
- The incision is closed with sutures and your foot is placed in a splint.
The splint is worn for a period of 6-12 weeks during which time you must not bear any weight on the leg. After this period, the foot is placed in a walking boot with minimal weight bearing and gentle ankle movements. Physical therapy is recommended for at least 3-4 months to improve strength and mobility. More strenuous exercises can be gradually introduced after a minimum of 3 months. For the first 6 months after surgery, you are advised to wear a lace-up ankle brace during sports activities.
When compared to syndesmosis using screws, the TightRope method has the following advantages:
- Allows normal motion at the syndesmosis
- Reduces the risk of pain caused by hardware
- Eliminates the possibility of screw breakage
- Allows earlier weight-bearing and return to motion and activity
- Prevents the need for a second surgery
- Repeated stress does not cause failure of the device
- Helpful in cases of osteoporotic bone
- No need for removal
Risks and complications
As with any surgery, syndesmosis surgery with tightrope fixation may include certain risks and complications such as bleeding, blood clots, infection, and damage to nerves and blood vessels. There is also a risk of fracture of the fibula and skin irritation.