Graphical presentation of the range of hip and knee rotations for clinical evaluation of gait

Globographic visualisation of three dimensional joint angles

Three different methods for describing three dimensional joint angles are commonly used in biomechanics. The joint coordinate system and Cardan/Euler angles are conceptually quite different but are known to represent the same underlying mathematics. More recently the globographic method has been suggested as an alternative and this has proved particularly attractive for the shoulder joint. All three methods can be implemented in a number of ways leading to a choice of angle definitions. Very recently Rab has demonstrated that the globographic method is equivalent to one implementation of the joint coordinate system. This paper presents a rigorous analysis of the three different methods and proves their mathematical equivalence. The well known sequence dependence of Cardan/Euler is presented as equivalent to configuration dependence of the joint coordinate system and orientation dependence of globographic angles. The precise definition of different angle sets can be easily visualised using the globographic method using analogues of longitude, latitude and surface bearings with which most users will already be familiar. The method implicitly requires one axis of the moving segment to be identified as its principal axis and this can be extremely useful in helping define the most appropriate angle set to describe the orientation of any particular joint. Using this technique different angle sets are considered to be most appropriate for different joints and examples of this for the hip, knee, ankle, pelvis and axial skeleton are outlined.

Advanced multimodal visualisation of clinical gait and fluoroscopy analyses in the assessment of total knee replacement

Traditional gait and fluoroscopy analysis of human movement are largely utilised but are still limited in registration, integration, synchronisation and visualisation capabilities. The present work exploits the features of a recently developed software tool based on multimodal display (Data Manager developed within the EU-funded project 'Multimod') in an exemplary clinical case. Standard lower limb gait analysis, comprising segment position, ground reaction force and EMG data collection, and three-dimensional fluoroscopy analysis at the replaced joint were performed in a total knee replacement patient while ascending stairs. Clinical information such as X-rays and standard scores were also available. Data Manager was able to import all this variety of data and to structure these in an original hierarchical tree. Bone and prosthesis component models were registered to corresponding marker position data for effective three-dimensional animations. These were also synchronised with corresponding standard video sequences. Animations, video, time-histories of collected and also processed data were shown in various combinations, according to specific interests of the bioengineering and medical professionals expected to observe and to interpret this large amount of data. This software tool demonstrated to be a valuable means to enhance representation and interpretation of measurements coming from human motion analysis. In a single software, a thorough and effective clinical and biomechanical analysis of human motion was performed.

The influence of the length of lower-limb prosthesis on spinal kinematics11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors(s) or upon any organization with which the author(s) is/are associated

OBJECTIVE

To examine the immediate effects of a change in prosthetic length on the kinematics of the lumbar spine in lower-limb amputees.

DESIGN

An experimental study with repeated measurements of lumbar spine movements under conditions of different prosthetic lengths.

SETTING

A free-standing rehabilitation center in the United Kingdom.

PARTICIPANTS

Twenty unilateral below-knee amputees.

INTERVENTION

Patients performed anatomic movements of the lumbar spine in standing and a sit-to-stand activity. Changes in prosthetic length were produced by placing a wooden block under the prosthetic and sound legs.

MAIN OUTCOME MEASURES

The positions of the pelvis and the lumbar spine in standing and the movement patterns of the lumbar spine were recorded by an electromagnetic tracking device.

RESULTS

A change in prosthetic length produced lateral tilt of the pelvis and lateral bending of the spine in standing. The mean maximum magnitudes of lateral bending and axial rotation toward the sound and prosthetic sides were different. Subjects exhibited lateral bending and axial rotation when they performed the flexion movement. There were also changes in the direction of coupling between lateral bending and axial rotation in some subjects.

CONCLUSION

A change in prosthetic length or leg-length inequality altered the kinematics of the lumbar spine.