- Email: [email protected]
FUNCTIONAL ASSESSMENT OF THE SHOULDER COMPLEX USING 3D MOTION ANALYSIS TECHNIQUES
Poster P-42
Human Motion
S415
FUNCTIONAL ASSESSMENT OF THE SHOULDER COMPLEX USING 3D MOTION ANALYSIS TECHNIQUES Barry Lovern (1), Richard Evans (2), Lianne Jones (1) Sam Evans (1), Lindsay Stroud (1), Cathy Holt (1)
1. Institute of Medical Engineering and Medical Physics, Cardiff School of Engineering, Cardiff University, Wales, UK. 2. Dept. Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK.
0
50 40 30 20
(a)
10 0 0
50
100
Flexion Angle (˚)
150
Anterior Tilt (˚)
Orthopaedic surgeons use a range of observations and physical examinations to diagnose shoulder pathologies. This can be far from straightforward as it is largely dependant on their prior experience and training. It is hypothesised that more accurate clinical diagnosis and prognosis could be possible through further understanding of the kinematics of the shoulder. Non-invasive motion analysis techniques to monitor shoulder function have been developed at Cardiff University. The technique serves as a basis for a diagnostic tool with practical applications including prediction of outcome for surgical intervention and functional analysis of joint prosthesis design.
the AC joint ROM which was up to 7 times larger. It is hypothesised that this may be due to the use of skin markers based on the findings of de Groot (1997). Protraction Angle (˚)
Introduction
-10
0
50
100
150
-20 -30 -40
(b)
-50
Abduction Angle (˚)
Figure 2: Motion profiles for the scapulothoracic articulation. Solid lines: Static. Small dashes: Static Adjusted. Large dashes: Dynamic. (a) protraction during flexion, (b) anterior tilt during abduction
Discussion
Methods Five subjects (M:F 4:1 mean age 26.8 ± 5 years) with no previous history of shoulder pathology or instability were fitted with retro-reflective markers to establish body segment and joint coordinate systems as per International Society of Biomechanics recommendations (Wu, 2005). Static measurements at 10˚ increments of elevation in the coronal and sagittal planes were recorded. The test was repeated with marker positions on the scapula manually adjusted as necessary at each increment to account for errors caused by movement of the scapula under the skin. A frame fitted with retroreflective markers was used to guide arm elevation (figure 1). A series of dynamic measurements were also taken. (a)
(a)
(b)
(b)
Figure 1: Subject elevates arm using frame for guidance; (a) abduction, (b) flexion
Quantifying the errors caused by skin-marker discrepancies in motion analysis of the shoulder complex allows the validity of motion models generated to be determined. There is minimal difference between the static and static adjusted rotation values (<2˚). This is less than the errors of 2˚ associated with palpation and the errors associated with noise and inter subject difference (33% and 55% respectively) (de Groot, 1997). Comparing static and dynamic measurements aids in the further understanding of the biomechanics of the shoulder complex. This consequently leads to assessments of the validity of dynamic motion models used, for example, in tasks of daily living. During dynamic abduction, the motion profiles and ROM's were similar to the static values with occasional divergence either at low or high elevations. During flexion large differences were observed for protraction of the scapulothoracic articulation (figure 2a). Smaller differences were seen during anterior tilt of the acromioclavicular joint and scapulothoracic articulation. Further testing is required to determine at what elevations these differences occur and to develop a viable hypothesis as to their cause.
Results Complete kinematic descriptions of the shoulder were obtained for the five subjects. Motion patterns and ranges of movement (ROM) are similar to those reported in the literature (Meskers 1998), (van der Helm 1995) with the exception of
16th ESB Congress, Posters
References Wu et al., 2005, J. Biomech., 38, pp. 982-992 Meskers et al.,1998, Clin Biomechanics 12 280-292 Van der Helm et al.,1995 J. BiomechEng;177:27-40 de Groot Clinical Biomech 12, 7/8, pgs. 461-472
Journal of Biomechanics 41(S1)
Human Motion
S415
FUNCTIONAL ASSESSMENT OF THE SHOULDER COMPLEX USING 3D MOTION ANALYSIS TECHNIQUES Barry Lovern (1), Richard Evans (2), Lianne Jones (1) Sam Evans (1), Lindsay Stroud (1), Cathy Holt (1)
1. Institute of Medical Engineering and Medical Physics, Cardiff School of Engineering, Cardiff University, Wales, UK. 2. Dept. Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK.
0
50 40 30 20
(a)
10 0 0
50
100
Flexion Angle (˚)
150
Anterior Tilt (˚)
Orthopaedic surgeons use a range of observations and physical examinations to diagnose shoulder pathologies. This can be far from straightforward as it is largely dependant on their prior experience and training. It is hypothesised that more accurate clinical diagnosis and prognosis could be possible through further understanding of the kinematics of the shoulder. Non-invasive motion analysis techniques to monitor shoulder function have been developed at Cardiff University. The technique serves as a basis for a diagnostic tool with practical applications including prediction of outcome for surgical intervention and functional analysis of joint prosthesis design.
the AC joint ROM which was up to 7 times larger. It is hypothesised that this may be due to the use of skin markers based on the findings of de Groot (1997). Protraction Angle (˚)
Introduction
-10
0
50
100
150
-20 -30 -40
(b)
-50
Abduction Angle (˚)
Figure 2: Motion profiles for the scapulothoracic articulation. Solid lines: Static. Small dashes: Static Adjusted. Large dashes: Dynamic. (a) protraction during flexion, (b) anterior tilt during abduction
Discussion
Methods Five subjects (M:F 4:1 mean age 26.8 ± 5 years) with no previous history of shoulder pathology or instability were fitted with retro-reflective markers to establish body segment and joint coordinate systems as per International Society of Biomechanics recommendations (Wu, 2005). Static measurements at 10˚ increments of elevation in the coronal and sagittal planes were recorded. The test was repeated with marker positions on the scapula manually adjusted as necessary at each increment to account for errors caused by movement of the scapula under the skin. A frame fitted with retroreflective markers was used to guide arm elevation (figure 1). A series of dynamic measurements were also taken. (a)
(a)
(b)
(b)
Figure 1: Subject elevates arm using frame for guidance; (a) abduction, (b) flexion
Quantifying the errors caused by skin-marker discrepancies in motion analysis of the shoulder complex allows the validity of motion models generated to be determined. There is minimal difference between the static and static adjusted rotation values (<2˚). This is less than the errors of 2˚ associated with palpation and the errors associated with noise and inter subject difference (33% and 55% respectively) (de Groot, 1997). Comparing static and dynamic measurements aids in the further understanding of the biomechanics of the shoulder complex. This consequently leads to assessments of the validity of dynamic motion models used, for example, in tasks of daily living. During dynamic abduction, the motion profiles and ROM's were similar to the static values with occasional divergence either at low or high elevations. During flexion large differences were observed for protraction of the scapulothoracic articulation (figure 2a). Smaller differences were seen during anterior tilt of the acromioclavicular joint and scapulothoracic articulation. Further testing is required to determine at what elevations these differences occur and to develop a viable hypothesis as to their cause.
Results Complete kinematic descriptions of the shoulder were obtained for the five subjects. Motion patterns and ranges of movement (ROM) are similar to those reported in the literature (Meskers 1998), (van der Helm 1995) with the exception of
16th ESB Congress, Posters
References Wu et al., 2005, J. Biomech., 38, pp. 982-992 Meskers et al.,1998, Clin Biomechanics 12 280-292 Van der Helm et al.,1995 J. BiomechEng;177:27-40 de Groot Clinical Biomech 12, 7/8, pgs. 461-472
Journal of Biomechanics 41(S1)