*2.3. Surgical Procedures*

The decision for TTCA or TTA on the basis of the objectifiable radiological criteria was largely guided by the surgeon's personal experience, the expected osteoarthritis of the subtalar joint, and the patient's expectations. Uniform criteria could only be completely delimited at follow-up. The surgical procedures were performed under general anesthesia or, less frequently, under spinal anesthesia, and a tourniquet was obligatorily applied to the thigh. The patient was placed in a supine position for both procedures.

For TTCA, the approach was usually along the lateral malleolus, which is osteotomized and decorticated 5–10 cm proximal to the tip of the malleolus, depending on the size of the patient and pre-ordered destruction of the ankle joint. The tibiotalar and subtalar joint was then dissected via this approach, with the removal of any remaining cartilage and resection of the destroyed subchondral sclerosis. All TTCAs were performed by implantation of a hindfoot fusion nail with 5◦ valgus. The diameter and length of the nail were chosen to be between 150 mm and 300 mm according to preoperative planning and intraoperative findings (Figure 2). A shorter nail with a diameter of 12 mm was the most common. Interposition autologous or allogenic cancellous bone grafting was performed in less than 20% of cases.

(**a**) (**b**)

**Figure 2.** Pre- and postoperative radiographic findings of end-stage posttraumatic arthritis of the left ankle of a 79-year-old male treated with a tibiotalocalcaneal arthrodesis (TTCA) T2™ Ankle Arthrodesis Nail, 150 × 12 mm. (**a**,**b**) Anteroposterior view, preoperative. (**c**,**d**) Anteroposterior view, 3 months postoperative.

TTA was regularly performed via an anterior approach between the tibialis anterior and the extenso hallucis longus tendon. After the prescribed preparation of the joint, a fusion was performed by inserting 2–3 converging cannulated screws (diameter of 6.5 or 8 mm) or an anterior fusion plate (Figure 3). Other approaches, such as lateral, posterolateral, and medial, as well as combined approaches, were also used where necessary. Nevertheless, treatment via the anterior approach was the most common, at over 80%. Regardless of the technical implementation, both the TTCA and the TTA were designed to be neutral in both the coronal and the sagittal plane, with a physiological valgus of the hindfoot of 5◦.

(**a**) (**b**)

**Figure 3.** Pre- and postoperative radiographic findings of end-stage posttraumatic arthritis of the left ankle of a 44-year-old male treated with tibiotalar arthrodesis (TTA) using cannulated screws (diameter 6.5 mm). (**a**,**b**) Anteroposterior view, preoperative. (**c**,**d**) Anteroposterior view, 8 weeks postoperative.
