Preoperative gait characterization of patients with ankle arthrosis Michael Khazzam a,b, * , Jason T. Long a,b , Richard M. Marks a , Gerald F. Harris a,b a Department of Orthopaedic Surgery, Medical College of Wisconsin, 9200 West Wisconsin Avenue, PO Box 26099, Milwaukee, WI 53226, USA b Orthopaedic and Rehabilitation Engineering Center (OREC)/Marquette University/Medical College of WI, USA Received 15 February 2005; received in revised form 16 May 2005; accepted 17 July 2005 Abstract The purpose of this study was to evaluate the kinematic changes that occur about the foot and ankle during gait in patients with degenerative joint disease (DJD). By comparing a normal adult population with what was found in the DJD population we determined how the motion of theses groups differed, thereby characterizing how this pathology affects foot and ankle motion. A 15-camera Vicon Motion Analysis System was used in conjunction with weight bearing radiographs to obtain three-dimensional motion of the foot and ankle during ambulation. The study was comprised of 34 patients and 35 ankles diagnosed with DJD (19 men and 15 women) of the ankle and 25 patients with normal ankles (13 men and 12 women). Dynamic foot and ankle motion was analyzed using the four-segment Milwaukee Foot Model (MFM). The data from this model resulted in three-dimensional (3D) kinematic parameters in the sagittal, coronal, and transverse planes as well as spatial-temporal parameters. Patient health status was evaluated using the SF-36 Health Survey and American Orthopaedics Foot and Ankle Society (AOFAS) hindfoot scores. The DJD group showed significant differences ( p < 0.001) as compared to normals with prolonged stance time, shortened stride length, reduced cadence and a walking speed which was only 66.96% of normal. Overall, kinematic data in the DJD cohort showed significant differences ( p < 0.001) in all planes of motion for tibial, hindfoot and forefoot motion as compared to normals. The average preoperative AOFAS hindfoot score was 26. DJD of the ankle results in decreased range of motion during gait. This decreased range of motion may be related to several factors including bony deformity, muscle weakness, and attempts to decrease the pain associated with weight bearing. To date there has not been a study which describes the effect of this disease process on motion of the foot and ankle. These findings may prove to be useful in the pre-operative assessment of these patients. # 2005 Elsevier B.V. All rights reserved. Keywords: Foot and ankle kinematics; Gait; Ankle arthrosis 1. Introduction Pain and loss of motion associated with degenerative joint disease (DJD) of the ankle can result in devastating consequences. Causes of these degenerative changes include traumatic injuries, abnormal ankle joint biome- chanics (i.e. chronic ankle instability), and less commonly primary osteoarthritis, rheumatoid arthritis, inflammatory arthropathy, hemochromatosis, infection, neuropathic arthropathy, and tumor [1–3]. The true prevalence of ankle DJD has been difficult to define as a result of variation in degenerative changes per etiology and clinical correlation. Lindsjo et al. [4], in a follow-up study of 306 operatively treated ankle fractures, reported the develop- ment of posttraumatic arthritis in 14% of patients [3,4]. Traumatic injury of the ankle is the most common etiology associated with DJD [3]. Development of post traumatic ankle arthrosis is precipitated by chronic eccentric loading (progressive uneven wear) of the joint as a result of angular deformity [5]. Fractures associated with posterior mal- leolar injuries are more prone to develop DJD when the posterior malleolus has not been anatomically reduced [2,3,5,6]. Chronic ankle instability leading to degenerative changes is due to lateral ligament laxity resulting in damage to the medial side [3,7]. All of these pathologies cause irreversible destruction of the tibiotalar articular cartilage, chronic cartilage overloading from articular incongruity, and eventual destruction of the joint space, resulting in pain and deformity. www.elsevier.com/locate/gaitpost Gait & Posture 24 (2006) 85–93 * Corresponding author. Tel.: +1 414 805 7456. E-mail address: drkhazzam@yahoo.com (M. Khazzam). 0966-6362/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.gaitpost.2005.07.006