Custom 3D-printed Total Talar Prostheses Restore Normal Joint Anatomy Throughout the Hindfoot

Abstract

Category: Hindfoot Introduction/Purpose: Third generation total talar prostheses (TTP) are viable options for talar avascular necrosis (AVN) in the absence of neighboring joint pathology. The use of modern three-dimensional (3D) printing allows for the production of custom implants that exactly mimic the patient’s anatomy. The aim of this study is to determine the accuracy of 3D printing in reproducing a synthetic talus, and in doing so, restoring more normal anatomic relationships. We hypothesize that this mode of replication will restore and maintain normal radiographic alignment of the ankle, subtalar, and forefoot joints in the setting of talar AVN. Methods: A retrospective analysis was performed on all patients undergoing TTP implantation for the treatment of talar AVN between 2016 and 2017. Pertinent demographic and operative factors were recorded. Radiographic measurements were taken pre- and post-operatively to determine native talar dimensions, TTP implant dimensions, and the corresponding radiographic alignment about the forefoot, hindfoot, and ankle. Results: Fourteen patients, treated for AVN between 2016-2017, were identified in our cohort. Talar arc length and width were not found to be significantly changed, however talar height was significantly increased with use of TTP. Five alignment dimensions were measured (tibiotalar alignment, talar tilt angle, Boehler’s angle, talar declination angle, and Meary’s Angle), of which, only talar tilt angle was significantly changed. Instances of Meary’s angle correction were observed in cavus and planus foot deformity. Conclusion: This study represents the largest case series of TTP performed in the United States, and is the first to investigate the 3D printed TTP. As a proof-of-concept, 3D printed TTP was successful in restoring talar height and talar tilt in the setting of AVN. Additionally, the procedure maintained normal alignment in non-pathologic joints. Total talar prosthesis, based on our cohort, is a viable option to restore more normal anatomic alignment.

Three dimension printing talar prostheses for total replacement in talar necrosis and collapse

“…In this way, complete matching of the talar prosthesis and the surgical operability of implantation were assured. Joseph Tracey reported no significant changes in the talar width and arc length in 14 patients who underwent the custom 3D-printed total talar prostheses replacement; however, the talar height was significantly increased, and Meary's angle was decreased [17]. In this study, the talar height and Meary's angle were significantly changed, which is similar to the literature.…”

“…Functional exercises of dorsiflexion and flexion were performed to improve the range of ankle motion. The accuracy of the postoperative reconstruction with respect to the preoperative plan was evaluated in terms of the talar arc length, talar height, talar width, tibial alignment angle, talar tilt angle, Bohler's angle, and Meary's angle [17]. As well as strict follow-up from the first day after operation, imaging data were taken regularly and compared with those before operation (Fig.…”

3D Printed Total Talus Replacement for Avascular Necrosis of the Talus

“…A recently published study on the implant design used in this paper demonstrated that this custom 3D printed implant restored native talar anatomy with regard to talar height and talar tilt. 19 The improvement in self-reported pain following TTR is not surprising given the significant improvement in function discussed previously. It is important to note that the final mean VAS score in the present study was 4; although a significant improvement was seen, some patients still reported pain.…”

Patient-specific three-dimensional printed hemi talar prostheses for the treatment of talar osteonecrosis, case report and literature review

“…Recently, some authors published their results using different total talar replacement. 14–16 The overall survival rate varies from 85% to 100%. Although this kind of procedures seems to be technically easy to perform, it does not allow too many options in case of revision surgery.…”

“…13 Also, in order to maintain mobility, some authors published their results using a total talar replacement such as alumina ceramic prosthesis, 14 stainless-steel talar body prosthesis 15 and nickel-plated cobalt implants. 16…”