Brief report Graphical presentation of the range of hip and knee rotations for clinical evaluation of gait Pei Lai Cheng 1 , Mark Pearcy * School of Mechanical, Manufacturing and Medical Engineering, Queensland University of Technology, GPO Box 2434, 2 George Street, QLD 4001 Brisbane, Australia Received 28 September 1999; accepted 23 August 2000 Abstract Objective. This paper reports a method of using a multi-axis graph to represent the range of rotations at the hip and knee joints during gait for clinical evaluation of a patient's performance. Design and methods. The multi-axis graph uses 12 symmetrically arranged axes to represent each component of range of rotations at the hip and knee joints of both legs. The range of joint rotations of thirteen normal subjects and two patients were measured using an electromagnetic motion tracking system with four foot switches. Results. The range of joint rotations of normal subjects shows a symmetrical star in the multi-axis graph. Abnormal function of a patient shows an asymmetrical star. Conclusions. This representation provides a simple way to examine a patient's performance in a time eective manner. Relevance In clinical practice, the multi-axis representation of joint rotations can be used as an initial evaluation of a patient's performance to identify problems for further investigation. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: Range of motion; Biomechanics; Hip and knee joints; Gait analysis; Joint rotation 1. Introduction Gait analysis allows comprehensive information to be collected as a large volume of data of kinematic and kinetic quantities. How to represent the results to clini- cians is of crucial importance for eective use of gait analysis as a clinical tool in assessment of patients' performance and clinical decision-making [1,2]. In clin- ical practice, range of joint rotations is one of the major concerns, especially for patients with total hip or total knee joint replacement [3±5]. The range of the hip and knee joint rotations during gait (joint excursion) is usually evaluated from two presentations, graphical presentation of each component of the joint rotations as a time series and presentation of some signi®cant values in tables. Graphical presentation requires 12 curves to show an overall view of rotation at the hip and the knee joints of both legs. It takes considerable time to examine these curves and to explain their implications to a clini- cian, especially for a large number of subjects. Using a table, important characteristics can be summarized. However, inclusion of many numbers in a large table may lose the simplicity of this form of presentation. The purpose of this paper is to report a method of using a multi-axis graph to represent rotational excursions of the hip and knee joints during gait in a single plot that could be used in clinical evaluation of a patient's performance. 2. Methods Thirteen normal subjects (32 yr (SD, 6), six males, seven females) without musculoskeletal disease and two patients, patient 1 (70 yr, female) with left knee joint replacement and patient 2 (68 yr, male) with right knee joint replacement, participated in this study with written consent. The patients were part of a much larger trial and are used here to demonstrate the technique for data presentation. Four walks along a 6 m walkway were recorded for each normal subject at each of two sessions Clinical Biomechanics 16 (2001) 84±86 www.elsevier.com/locate/clinbiomech * Corresponding author. E-mail address: m.pearcy@qut.edu.au (M. Pearcy). 1 Present address: Department of Mechanical Engineering, Queen's University, Kingston, Canada K7L 3N6. 0268-0033/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 8 - 0 0 3 3 ( 0 0 ) 0 0 0 6 9 - 3