Clinical short-term analysis and effectiveness evaluation of optimally designed customized artificial talus implants

Abstract

Avascular necrosis (AVN) of the talus is a rare but debilitating condition that can lead to joint collapse and significant functional impairment. In advanced stages, joint-preserving surgical options are limited. This study aimed to develop a lightweight, patient-specific 3D-printed total talar implant and evaluate short-term clinical and radiographic outcomes in patients with idiopathic talar necrosis. A total of eight patients were approved for inclusion in this prospective clinical trial under the rare-disease framework established by the Ministry of Food and Drug Safety (MFDS) of Republic of Korea. Six patients underwent total talar arthroplasty starting in July 2023. As of this interim analysis, three patients had completed both the 6-week and 3-month postoperative follow-up assessments and were included in the analysis. The mean follow-up duration was 16 weeks. Radiographs were obtained at each follow-up visit to assess implant positioning and structural integrity. Clinical outcomes were evaluated using the visual analog scale (VAS), the Foot and Ankle Outcome Score (FAOS), and ankle range of motion (ROM). Preoperatively, all three patients reported VAS scores ranging from 7 to 10, which decreased by 3 to 7 points postoperatively. The median final FAOS improved from 48.0 [IQR: 17-76] to 61.0 [IQR: 48-72] at 3 months. Improvements were observed in pain and daily living function subscales, while lower gains were noted in sports and recreational activities. ROM was generally maintained or improved postoperatively, with plantarflexion increasing from a median of 40 degrees [IQR: 0-45] to 40 degrees [IQR: 35-55], and dorsiflexion maintained at a median of 10 degrees. These preliminary findings suggest that total talar replacement using a patient-specific implant may preserve joint function and improve early clinical outcomes in selected patients with advanced talar AVN. Ongoing follow-up is required to assess mid- and long-term safety and implant durability.Clinical trial registration: Ministry of Food and Drug Safety (MFDS), approval number 2,023,000,218 / Approval date April 12, 2023.