Ankle arthritis in the setting of distal tibial and calcaneal cysts: A case report of a novel staged treatment with bone graft substitute and total ankle arthroplasty

<h2>Abstract</h2> Total ankle arthroplasty is a selective procedure that can be highly advantageous for the appropriate candidate. A primary indicator for a positive outcome of the procedure is adequate bone stock, and there is limited literature regarding total ankle arthroplasty in the setting of inadequate bone stock. Most literature refers to periprosthetic bone cysts after a total ankle replacement. This case study documents a 52-year-old male with long-standing ankle arthritis and distal tibial (2.5 × 2.5 × 1.3 cm, volume: 8.13 cm³) and calcaneal (3.8 × 3.5 × 3.0 cm, volume: 39.9 cm³) cysts. Here, a novel treatment was performed utilizing a staged procedure of bone graft substitute in the setting of distal tibial and calcaneal cysts before a total ankle arthroplasty. Preoperative CT imaging was used to evaluate the severity and size of the cysts prior to bone graft substitute implementation. CT imaging was also used postoperatively to confirm consolidation of the cysts. The patient was subsequently followed for two years after the final procedure and was noted to have a stable distal tibial plafond with sufficient ankle joint range of motion with the Wright Medical Inbone Total Ankle Replacement system® (Memphis, Tennessee, USA) by primarily using bone graft substitute for the tibial and calcaneal cysts and later performing a total ankle replacement. The patient had a follow-up period of 24 months after the final procedure with a preoperative AOFAS score of 34, which progressed to 79 postoperatively. As total ankle replacements are increasing in popularity, this novel staged treatment appears to be a safe and viable option to prevent ankle arthrodesis in patients with tibial and calcaneal cysts. <h3>Level of Clinical Evidence</h3> 4