Category: Ankle Arthritis Introduction/Purpose: There is paucity of literature on quantitative gait changes in patients with increased coronal plane deformity along with end stage ankle arthritis. We aimed to study the difference in spatial temporal parameters of gait and patient reported functional measure in patients with end stage arthritis and no coronal plane deformity vs. varus deformity of >10? Methods: All patients diagnosed with end stage arthritis between April 2016 and December 2017 underwent an objective gait assessment using Tekscan system (BioSense Medicals, UK) as part of routine clinical practice. Of this cohort, patients with bilateral ankle arthritis, previous reconstructive surgery, inflammatory arthritis, hip and knee arthritis, spinal pathology and underlying neurological conditions were excluded. Patients with unilateral ankle arthritis for a diagnosis of osteoarthritis or post traumatic arthritis were included in this study. These patients were grouped into Group A (no coronal plane deformity) vs. Group B (varus deformity of more than 10?). In these patients differences were studied between the groups for temporal spatial parameters of gait and functional disability levels measured by MOX-FQ scores. Statistical tests included normality tests, student t’tests, chi square evaluation and analysis of variance tests with SPSS. Results: Of 33 patients, 22 were in Group A (N=22) and 10 in Group B (N=10). There was no difference in mean age between groups (61.5 vs. 65.07; p=0.335; diagnosis was predominantly OA in both groups MOX-FQ: - There were similar levels of pain (p=0.570), difficulty with walking / standing (p=0.492) and restriction in social activities (p=0.869) reported Quantitative gait measures: - For spatial parameters, there was no difference between groups; p>0.05. - For temporal parameters, there was decreased step time(s) (0.67 vs. 0.61) and mid stance times (0.38 s vs. 0.30 s) in Group B; borderline statistical significance (p=0.052). - There was increase in stride velocity measured in Group B (79.1 ± 22.7 m/s) compared to Group A (64.0 ± 18.1 m/s), (p=0.05). Conclusion: - Although there were no differences in functional levels of pain, difficulty with walking / standing and restriction in social activities, measured by MOX-FQ, there were differences observed in objective gait parameters. - Patients in both groups demonstrated antalgic gait patterns; this was slightly increased in varus group. - There is a trend for reduction in temporal parameters and stride velocity in patients with end stage ankle arthritis and coronal plane deformity >10?, when compared to patients with end stage arthritis and no coronal plane deformity - Larger clinical study with increased sample size is required to confirm these findings.