## 3 Results  
Between December 2019 and May 2021, 34 patients with degenerative ankle arthropathy and candidates for anterior TAR surgery with mobile-bearing, 3-component prostheses Vantage Exactech(r) were evaluated for eligibility (Exactech, Gainesville, FL, USA). Of these, 14 were excluded (10 did not meet the pre-defined inclusion and exclusion criteria, and 4 did not consent to participation in the study). Finally, 20 patients were selected, properly informed, and enrolled. At the time of the final follow-up (10 post-operative months), 2 patients were lost (1 patient underwent a removal of the components for periprosthetic infection, and 1 patient requested to be excluded from the study already started), with a drop-out rate lower than the average described in the literature for prospective studies [18]. Therefore, patients undergoing a complete procedure with clinical and instrumental pre-operative and post-operative evaluation at the end of the follow-up were 18 (13 males and 5 females) of average age 59 \(\pm\) 10.28 years (range 42-74). The AOFAS and SF-36 (in its physical domains F and mental M) scores showed a statistically significant increase between baseline and final follow-up, with \(p\)-value < 0.005. The AOFAS ankle-hindfoot score improved from a mean pre-operative value of 33.7 (range 12-59, DS 13.65) to post-operative 85.9 (range 74-97, DS 8.26). The SF-36 score, in its two domains, F and M, showed an increase from pre-operative average values of 33.3 (range 22.8-49.5, DS 7.37) and 49.1 (range 31.9-63.1, DS 7.5), respectively, to post-operator values of 48.2 (range 43.6-56.6, DS 3.4) and 53.25 (range 40.4-60.7, DS 4.53) (Figure 3). The results of the postural tests performed using the DELOS System (DPPS) were analyzed and processed (with an inversely proportional ratio between score to stability). The mean values of the Stability Index (SI) on the affected limb were found to be 68.58% \(\pm\) 18.1 and 38.21% \(\pm\) 14.5 (open-eye (OE) and closed-eye (CE), respectively). In post-operative tests, the affected limb showed results slightly lower than in pre-operative, with an SI of 61.1% \(\pm\) 18.3 and 51.9% \(\pm\) 13.5 (OE and CE, respectively), with a pre-post \(\Delta\) not statistically significant. No patients reported complete autonomy, both OE and CE, in single-stance support on both limbs. The recorded average pre-operative autonomy was 85.6 \(\pm\) 19.6 with open eyes and 54.3 \(\pm\) 21.6 with closed eyes, while the post-operative mean values were 76.8 \(\pm\) 20.3 and 50 \(\pm\) 18.9 (respectively, with OE and CE), with a non-statistically significant difference. The mean SI values recorded for the healthy limb were pre-operative 86.9% \(\pm\) 4.5 and 52.9% \(\pm\) 16.1 (OE and CE, respectively) and post-operative 85.8% \(\pm\) 6.9 and 51.9% \(\pm\) 13.5 (OE and CE). The mean values of the autonomy on the healthy limb were 99.4 \(\pm\) 1.5 and 70.1 \(\pm\) 16.8 (OE and CE) in pre-operator tests, while in the final follow-up tests, were 99.1 \(\pm\) 2.9 and 69 \(\pm\) 17 (OE and CE). The average values were recorded, analyzed, and compared to the few related studies in the actual literature [20; 21; 27; 28]. The SI recorded for the affected limb, both pre- and post-operative, showed modest postural and proprioceptive stability, which translated into an increased risk of falling to the ground during single-stance support (Table 1). The differences between the affected and the healthy side are statistically significant (\(p<0.005\)), as opposed to the pre-post \(\Delta\).