Bilateral differences in gait mechanics following total ankle replacement: A two year longitudinal study ☆ Robin M. Queen a,b, ⁎, Robert J. Butler b,c , Samuel B. Adams Jr. a , James K. DeOrio a , Mark E. Easley a , James A. Nunley a a Department of Orthopaedic Surgery, Duke University Medical Center, Box 3956, Durham, NC 27710, USA b Michael W. Krzyzewski Human Performance Research Laboratory, DUMC 3435, Duke University Medical Center, Durham, NC 27710, USA c Division of Physical Therapy, Department of Community and Family Medicine, 2200 West Main St., Durham, NC 27705, USA abstract article info Article history: Received 14 August 2013 Accepted 27 January 2014 Keywords: Total ankle replacement Gait symmetry Walking mechanics Ankle arthritis Background: Following total ankle replacement (TAR) patients demonstrate improvements in gait. The purpose of this study was to assess the changes in gait symmetry from a pre-operative assessment through two years following TAR. Methods: Seventy-eight patients who received a primary TAR and had no contralateral pain were examined. Three-dimensional joint mechanics and ground reaction forces were collected during seven walking trials pre- operatively, and 1 and 2-years post-operatively. Data was analyzed using a 2 × 3 repeated measures ANOVA to determine significant differences between limbs and across time points (α = 0.05). Findings: Walking speed improved from pre-operative to each post-operative time point (P b .001; ES = 1.5). Peak dorsiflexion was not changed across time or between sides, however, the dorsiflexion angle at heel strike was in- creased on the nonsurgical side (P = 0.049; ES = 0.32). Peak plantar flexion moment (P b .001; ES = .80), stance (P b .001; ES = .29) and step time (P b .001; ES = .41) were improved from pre-op to 1 year post-surgery on the surgical side. Step (P b .001; ES = 1.2) and stride length (P b .001; ES = 1.2) demonstrated improvements across all time points, while the weight acceptance (P b .001; ES = .27) and propulsion ground reaction forces (P b .001; ES = .22) showed improvements between pre-op and 1 year post-op. Interpretation: The results of the study indicate that the patients are able to walk faster and demonstrate an improvement in gait symmetry; however, this improvement does not return the patient to a symmetric walking pattern by 2 years post-TAR. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Ankle arthritis is a debilitating condition that may lead to deformity, severe pain, functional disability, biomechanical changes, cartilage breakdown, and subsequent gait dysfunction (Abidi et al., 2000; Horisberger et al., 2009). Current estimates indicate that the burden of degenerative joint disease at the ankle is more than 50,000 new cases reported each year (Brown et al., 2006). While most hip and knee arthritis cases are primary, 70% of ankle arthritis is post-traumatic and the majority of remaining cases are caused by systemic disorders (Saltzman et al., 2005). Although gait changes and pain are the most notable signs and symptoms in patients with ankle arthritis, other measures such as quality of life and self-reported physical function are affected significantly with increasing ankle arthritis severity (Horisberger et al., 2009). The degree of physical impairment, as reported by the SF-36, that has been associated with ankle arthritis is re- ported to be equivalent to end stage kidney disease, congestive heart failure and end stage hip arthritis (Saltzman et al., 2006). Current surgi- cal treatment options for painful end stage ankle arthritis include total ankle replacement (TAR), ankle fusion (arthrodesis), and ankle distrac- tion arthroplasty; none of which have been identified as the optimal treatment (Saltzman et al., 2009). Limited studies have been completely examining changes in me- chanics in patients with end-stage ankle OA. However, previous litera- ture examining both TAR and fusion have indicated that patients with end-stage ankle arthritis walk significantly slower than 1.3 m/s, which is needed for successful and safe community ambulation as well as dem- onstrating significant limitations in ankle range of motion and ground reaction forces during walking (Brodsky et al., 2011; Detrembleur and Leemrijse, 2009; Hahn et al., 2012; Queen et al., 2012). With these sig- nificant limitations in mobility surgical intervention has become more common with ankle arthrodesis being the preferred treatment for many years. Improvements in gait mechanics have been reported more than one year following arthrodesis (Hahn et al., 2012). Patients demonstrated improved walking speed and stride length following Clinical Biomechanics xxx (2014) xxx–xxx ☆ Source of funding: No funding was received for this study. ⁎ Corresponding author at: Michael W. Krzyzewski Human Performance Lab, Department of Orthopaedic Surgery, Duke University Medical Center, Box 3435, Durham, NC 27710, USA. E-mail address: robin.queen@duke.edu (R.M. Queen). JCLB-03751; No of Pages 5 0268-0033/$ – see front matter © 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.clinbiomech.2014.01.010 Contents lists available at ScienceDirect Clinical Biomechanics journal homepage: www.elsevier.com/locate/clinbiomech Please cite this article as: Queen, R.M., et al., Bilateral differences in gait mechanics following total ankle replacement: A two year longitudinal study, Clin. Biomech. (2014), http://dx.doi.org/10.1016/j.clinbiomech.2014.01.010