Ankle Fractures
Minimally Invasive Fixation
Is percutaneous fixation of ankle fractures possible? And who is a candidate for percutaneous fixation of ankle fractures?
Candidates for percutaneous fixation of ankle fractures include patients with diabetes, patients with peripheral vascular disease, elderly patients, immunosuppressed patients, and patients with severe soft tissue compromise. These patients may be a candidate especially if reduction of the fracture can be obtained in a closed fashion.
Precise anatomic reduction of the fibula, the medial malleolus, and the syndesmosis is important in achieving excellent functional outcome after ankle fracture. The talus must be reduced in the mortise and any lateral talar subluxation is an indication for surgery.
Open surgery usually utilizes plates and screws, and even with open surgery, the syndesmosis reduction and fixation may not be perfect- there may be a malreduction. Open surgery requires dissection of the traumatized soft tissue, and wound complications and infection may occur, especially in certain groups of patients. However, surgery is better than conservative treatment, especially if it is done properly and after the soft tissue condition improves. Sometimes, the soft tissue condition does not improve, or it may take longer than usual to improve. I always thought that if we do fixation of the ankle percutaneously, we may reduce the incidence of soft tissue complications for these patients.
For the last several years, I have used percutaneous fixation of ankle fractures starting with the fibula while trying to also maintain the fibular length utilizing currently used landmarks. When you reduce the fibula, look for the Shenton’s line and the dime sign.
Then, use cannulated screws (4.5 or 6.5 mm cancellous screws). 6.5 mm screws are used if the bone is very osteoporotic and if the canal is wide. While doing so, we are trying to preserve the soft tissue envelope and decrease the potential risk of infection. The guide wire will be passed percutaneously across the fibular fracture and fluoroscopy should be used to confirm a good standing point and good reduction. The screw is inserted over the guide wire and then it is passed across the fracture, all while the fibular length is maintained. The fracture is kept in a reduced position with manual reduction techniques.
After fixing the lateral malleolus, the medial malleolus is fixed. To do so, reduction clamps are applied percutaneously and the screws are inserted over guide wires percutaneously. This is also fluoroscopy guided. Partially threaded cannulates screws are used for this procedure. In some cases, I will used three screws. Fixing the medial malleolus is not as easy as fixing the lateral malleolus.
I will often fix the medial malleolus first if the fibula is comminuted and if I think I am going to have a difficult time obtaining reduction of the fibula fracture and obtaining the length of the fibula. In these cases, fixing the medial malleolus first will help maintain the proper length of the fibula.
Sometimes, a small area of imperfection in the medial malleolus is accepted. However, the best cases for the percutaneous screws are the cases that do not have a medial malleolus fracture. If there is a medial malleolus fracture present, try not to accept more than a 2 mm step-off. If the reduction of the medial malleolus cannot be obtained, either open the fracture and reduce it or delay opening of the fracture until the soft tissue condition improves significantly.
After fixation of the lateral and medial sides, then the syndesmotic injury is treated with reduction and fixation. The reduction is achieved by using a reduction clamp to close and reduce the syndesmosis. The guide wire is then used, and the cannulated screws are inserted over the guide wire. Sometimes, I use several syndesmotic screws and I also sometimes use them in a converging or crossing manner, which is done for strength. Fluoroscopy is always used to show the appropriate reduction and fixation of the syndesmosis.
