Salvaging A Failed Ankle Replacement By Reconstructing The Talus

These authors present a guide to reconstructing the talus with a pantalar fusion and allograft of the femoral head in a patient with a failed ankle replacement.

A 71-year-old male with a past surgical history significant for a right knee replacement and left knee arthroscopy related having left ankle pain for several years. He could not recall a specific injury that caused the pain. The patient does not have diabetes or smoke. He is 5 feet 7 inches tall and weighs 178 pounds with a body mass index (BMI) of 27.98.

The lower extremity exam revealed edema at the left ankle in comparison to the right with a significant ankle varus deformity. The patient did not have neuropathy and his pedal pulses were palpable. His left ankle joint range of motion was limited. There was global pain with motion of the left ankle joint. Radiographs of the left ankle revealed end-stage degenerative joint disease at the tibiotalar joint with a varus deformity.  

We discussed conservative versus surgical management with the patient and due to the deformity, the discussions included primary fusion versus an ankle replacement. The patient decided to pursue a left ankle replacement. We obtained full length standing films prior to surgery.

We performed a left total ankle replacement with lateral collateral ligament reconstruction using the STAR Ankle (Small Bone Innovations) and BioComposite anchors (Arthrex). The patient’s postoperative course was unremarkable with progression to full weightbearing and return to recreational activities including downhill skiing.

The patient then began experiencing pain in the subtalar joint and described pain at the lateral aspect of the ankle distal to the fibula. Radiographs demonstrated a fracture of the talus with subsidence of the implant.  

Approximately 18 months after surgery, a single-photon emission computed tomography (SPECT-CT) scan of the left ankle revealed a complex talus fracture that included a horizontal fracture at the inferior margin of the prosthesis and a vertical fracture of the talar neck. Diffuse sclerosis was also present, which was consistent with osteonecrosis. In addition, the talar dome prosthesis fragment was rotated and displaced laterally.

Keys To The Successful Revision Surgery

Approximately 21 months after the initial ankle replacement surgery, the patient went to the OR for a revision including removal of hardware, a complete talectomy secondary to avascular necrosis, left iliac crest bone marrow aspiration and arthrodesis using a femoral head.

Intraoperatively, the talar component of the replacement was loose with posterior collapse while the tibial component was well fixed, which we removed with minimal bony resection. The talar head and medial aspect of the talus were not reconstructable so we performed a talectomy. Preparation of the subtalar joint, navicular, tibia and medial and lateral malleolus involved removing any remaining subchondral bone and cartilage. We shaped the femoral head and neck, and used the femoral head for the posterior aspect of the talus, directing the neck toward the navicular. After shaping the femoral head and neck, we infused the femoral head and neck with iliac crest bone marrow aspirate and demineralized bone matrix.

We fixated the tibiotalar joint with a 7.0 mm titanium compression screw anteriorly from the medial malleolus and exiting laterally. Placement of a 10 x 150 mm intramedullary nail helped obtain good compression through the tibia. We then placed two posterior-anterior calcaneal screws, one aimed slightly lateral down the anterior process and the other across the calcaneocuboid joint. We also placed a 4.5 mm partially threaded titanium screw across the talonavicular joint followed by a contoured locking plate. This stabilized both the ankle and the talonavicular joint. At the lateral aspect of the ankle, we placed a 4.0 mm partially threaded titanium screw from the fibula into the graft and the medial malleolus.

In Conclusion

This case illustrates an option for reconstruction of the talus with a pantalar fusion following a failed ankle replacement with avascular necrosis of the talus. Five months postoperatively, the CT scan demonstrates 80 percent osseous integration of the tibiotalar joint, talonavicular joint and subtalar joint without evidence of collapse. The next six to 12 months will determine if osseous integration of the femoral head continues, leading to a stable, long-term solution for the patient.  

Dr. Lake is board-certified in orthopaedic surgery by the American Board of Orthopaedic Surgery. He completed his foot and ankle fellowship at the Cleveland Clinic Foundation.  Dr. Lake is in private practice in Gilbert, Ariz.

Dr. Haddon is board-certified in foot surgery, reconstructive rearfoot and ankle surgery by the American Board of Foot and Ankle Surgery. He is a Fellow of the American College of Foot and Ankle Surgeons, and is a faculty member of the Podiatry Institute.  Dr. Haddon is in private practice in Gilbert, Ariz.

Dr. Lacy is a third-year resident at Maricopa Integrated Health Systems in Phoenix, Ariz.