Abstract
Conversion of painful ankle arthrodesis to total ankle arthroplasty (TAA) is a recognized salvage option in selected patients with failed fusion who desire restoration of motion. Prior distal fibular resection adds technical difficulty because it removes the normal lateral osseous buttress and may complicate implant support and stability.
We report a 70-year-old male with persistent left ankle pain and swelling after prior left ankle arthrodesis with screw fixation performed at an outside facility 18 months earlier. He was a nonsmoker with hypertension. Radiographs and computed tomography demonstrated nonunion of the ankle arthrodesis, retained screw fixation, and prior distal fibular resection. Revision ankle arthrodesis and conversion to TAA were discussed. The patient ultimately elected staged conversion to TAA after counseling regarding risks, including potential limb loss if salvage failed.
The first stage consisted of hardware removal. Eight weeks later, takedown of the nonunion and TAA were performed through an anterior approach using patient-specific planning and guides. Because of absent distal fibular support and concern regarding tibial bone stock, a stemmed tibial implant was selected. with flat-top talar component, and 10-mm polyethylene insert. Intraoperative stability was satisfactory. Achilles tendon lengthening was performed before closure.
The patient remained non-weightbearing for 4 weeks, transitioned to a walking boot with physical therapy for another 4 weeks, returned to normal shoe gear at 8 weeks, and normal activities at 3 months. At 36-month follow-up, he was doing well without any complications.
Introduction
Ankle arthrodesis remains a durable treatment for end-stage ankle arthritis, but painful nonunion, malunion, persistent pain, and functional limitation can complicate outcomes after fusion [ , ]. Conversion of a painful ankle arthrodesis to total ankle arthroplasty has become an accepted salvage strategy in carefully selected patients, with published case series, reviews, and systematic review data demonstrating improvement in pain and function in appropriately selected patients [ ,,,, ].
A particularly difficult scenario is conversion after prior distal fibular resection or an insufficient fibular buttress. The absent distal fibula removes conventional lateral stabilizing structures and complicates implant planning and reconstructive decision-making. Prior literature has specifically described takedown in the setting of insufficient fibula using allograft to reconstruct the lateral buttress [ ], whereas other review literature has argued that absence of the fibula should be considered an absolute contraindication to conversion [ ]. However, there is no previous literature, to our knowledge, that document an ankle arthrodesis takedown and conversion to total ankle arthroplasty with no fibula.
We report a staged conversion of a painful left ankle arthrodesis nonunion to stemmed total ankle arthroplasty in a patient with prior distal fibular resection, emphasizing patient selection, preoperative planning, intraoperative strategy, and early clinical outcome.
Case presentation
A 70-year-old man presented with persistent pain and swelling of the left ankle following ankle arthrodesis with screw fixation performed at an outside institution 18 months earlier. His symptoms had persisted for approximately 6 months, and he presented ambulating in a controlled ankle motion boot. His medical history was notable for hypertension and a nonsmoking status. He had previously undergone successful total ankle arthroplasty of the contralateral ankle and remained satisfied with that outcome at the time of encounter.
Weightbearing radiographs demonstrated nonunion of the ankle arthrodesis site, multiple retained screws, and complete absence of the distal fibula following prior fibular resection. Computed tomography confirmed the tibiotalar nonunion and was used to assess the residual tibial and talar bone stock available for reconstruction.
The patient was counseled regarding revision ankle arthrodesis and conversion to total ankle arthroplasty. Revision arthrodesis represented the more conventional salvage procedure; however, the patient strongly desired restoration of ankle motion and expressed limited confidence in repeat arthrodesis after failure of the index fusion. The patient’s satisfactory contralateral total ankle arthroplasty also influenced candidacy for a motion-preserving reconstruction and potential for a favorable outcome.
The principal concern regarding conversion arthroplasty was the absence of the distal fibula and its potential effect on lateral support and ankle stability. The risks, benefits, and uncertain long-term durability of total ankle arthroplasty in this setting were discussed in detail. The patient was also counseled that failure of the reconstruction could require revision arthroplasty, conversion to tibiotalocalcaneal arthrodesis, or, in the setting of an unsalvageable extremity, below-knee amputation. After shared decision-making, he elected staged conversion to total ankle arthroplasty.
Surgical management and technique
Treatment was performed in 2 stages. The first stage consisted of removal of the retained ankle arthrodesis hardware. Eight weeks later, the patient returned for takedown of the nonunion and conversion to total ankle arthroplasty. The interval between procedures permitted further assessment of the osseous anatomy, implant planning, and fabrication of patient-specific instrumentation.
Fig. 1 , Fig. 2 , Fig. 3 and Fig. 5
Preoperative anteroposterior and lateral radiographs of the left ankle demonstrating prior ankle arthrodesis with retained screw fixation, distal fibular resection, and nonunion at the fusion site.
Computed tomography of the left ankle confirming nonunion of the prior ankle arthrodesis.
Patient-specific preoperative plan for total ankle arthroplasty demonstrating implant templating and alignment for revision reconstruction in the setting of prior distal fibular resection.
Through a standard anterior approach, the ankle nonunion was exposed. The ankle remained in a rectus position following the failed arthrodesis; therefore, no additional coronal-plane corrective procedure or increased coronal balancing was required. A patient-specific alignment guide was positioned on the distal tibia, and guide placement was verified using large C-arm fluoroscopy in the anteroposterior and lateral planes ( Fig. 4 ). Accurate positioning was considered critical because the guide established the planned tibial resection level and overall component alignment.
