Cobalt-Chrome 3D-Printed Total Talus Replacement with and without Combined Total Ankle Replacement Improve Functional Scores and Radiographic Outcomes
Authors: Mitra Kishen , Anastasio Albert T. , Wu Kevin , Abar Bijan , Schweitzer Karl M. , Parekh Selene G. , Easley Mark E. , Adams Samuel B. 
Published: December 2024

Category:

Hindfoot; Ankle

Introduction/Purpose:

Collapse of the talus and peri-talar arthritis pose treatment challenges due to the anatomy and location of the talus as a keystone of the foot and ankle. Custom 3D-printed total talus replacement (TTR) and combined total ankle total talus replacement (TATTR) have emerged as treatment options for peri-talar arthritis, avascular necrosis of the talus and talus insufficiency. However, long-term data on the safety and efficacy of these implants is unknown due to the limited number of cases and short follow-up durations.

Methods:

This was a retrospective study to assess surgical outcomes of patients who underwent a TTR and TATTR with or without subtalar fusion. Patient demographics, intraoperative parameters, device related surgical and non-surgical events, imaging and clinical evaluations, and patient reported outcome (PRO) measures were compiled for each case. The Odds Ratio (OR) for secondary surgery was calculated for each binary outcome using univariate and multivariate logistic regression. The multivariable model included significant variables from the univariate analysis to address potential confounders. Pre- and postoperative radiographic measurements and range of motion were compared using pairwise t-tests. Pain VAS, PROMIS Pain Interference (PI), and PROMIS Physical Function (PF) scores were compared across all timepoints using one-way ANOVA (p< 0.05 significance level).

Results:

A total of 38 patients received a custom 3D-printed implant with mean follow-up time of 22.1 (range: 12-45) months. In this cohort, 7 (18.4%) required secondary surgery and 3 (7.9%) required removal of the implant. The mean time to secondary surgery was 19.9 (range: 11-32) months. Multivariate logistic regression revealed that patient diagnosis of depression was a significant predictor of secondary surgery with an OR 17.50 (p= 0.037). Significant postoperative improvements were observed in talocalcaneal height (p=0.005) and talar declination angle (p=0.013) for the TATTR group. VAS and PROMIS PI scores demonstrated an initial significant decrease in pain, but this improvement did not maintain significance at most recent follow-up. However, there was a significant increase in the PROMIS PF scores (p=0.037) at most recent follow-up.

Conclusion:

These results demonstrate that TTR and TATTR provide improvement in radiographic foot and ankle alignment and physical function. PRO findings suggest that patients are more active despite steady pain increase over time. Surgeons considering proceeding with either of these procedures should counsel patients about pain and functional outcomes as well as realistic expectations in patients with depression. Larger cohorts of patients should be studied to identify other high-risk groups and possible interventions. Future studies should investigate the association between diagnoses like depression and PROs.