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13.4 Biomechanical asymmetry in the lower limb duringobstacles-crossing following anterior cruciate ligament reconstruction
Chapter 13. Biomechanics and orthopaedic disorders
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Methods: 8 ACL patients walked and crossed obstacles of 3 heights (10, 20 and 30% leg lengths) before and 3 months after ACLR. Kinematic and kinetic data were measured using a motion analysis system (Vicon, Oxford Metrics, U.K.) and two force plates (AMTI, U.S.A.). An asymmetry index (AI, difference between sound and affected limbs/average of both limbs) was used to investigate the asymmetry of the joint kinematics and kinetics. Paired-t test was used for before after reconstruction comparisons (¢~ 0.05). Results: Significantly bigger AI values were found in the trailing knee crossing flexion angles and leading knee crossing flexor moments as well as the peak hip internal rotator moments of both limbs for all heights after ACLR. Discussion and Conclusion: The results suggest that ACLR did not help reduce the biomechanical asymmetry 3 months post-op. It may be associated with the persistent deficit of the muscle strength after surgery. Rehabilitation for a longer period of time may be needed to achieve better inter-limb coordination.
References [1] Kobayashi A., Higuchi H., Terauchi M., Kobayashi F., Kimura M. and Takagishi K. Muscle performance after anterior cruciate ligament reconstruction. International Orthopaedics 2004; 28: 48 51.
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References [1] Winter DA. Human balance and posture control during standing and walking. Gait Posture, 1995; 3:193 214.
Changes in postural control of patients with anterior cruciateligament dificiency
RW. Chiu 1, S.Y. Chen 1, H.C. Lin 1, H.C. Hsu 2. 1School of
Physical Therapy, China Medical University, China," 2Department of Orthopedics, China Medical University Hospital, China Introduction: Anterior cruciate ligament (ACL) not only plays
an important role on the passive stability of the knee joint but also provides proprioceptive feedback. ACL injury may cause the mechanical and neuromuscular changes of the knee joint and affect the balance function of these patients. The purpose of this study is to investigate the multi-sensory interactions on the postural control for the patients after the loss of ACL. Methods: Eight patients with unilateral ACL-deficient (ACLD) and eight matched control subjects were recruited. They were examined on PRO Balance Master with testing conditions including eyes open/close and fixed/swayed surface. Area, path, average velocity, and maximum velocity of center of pressure (COP) were obtained during the 20sec static stance. The percentage differences of sway (PDS) of these variables were calculated to reveal the quantitatively differences of vision and proprioception contribution to postural control between groups. Results: Compared with normal subjects, smaller PDSs for proprioception contribution in CoP area for vision and non-vision conditions while larger PDSs for visual contribution in CoP average velocity, and maximum velocity for stable surface condition were found (p < 0.05). Other variables demonstrated the similar trend but not reach statistical significance. Discussion and Conclusion: The findings in this study suggested that the ACLD patients increased their reliance on vision and decreased on proprioception. It implied that the ACL injury resulted in a re-distribution of the multi-sensory system for the postural control of the whole body.
[•
Methods: Three-dimensional movement, using the CODA motion analysis system, (Charnwood Dynamics UK) was obtained in 21 agematched healthy (9 males) and 18 ACLR subjects (10 males, mean time post surgery 6 yrs). During a 15 s, one-legged standing task postural sway was recorded, at 100Hz by two sensor units from 24 light emitting diodes placed on specific anatomical landmarks. Results: The data was exported and analysed in Mathcad 2001i and SPSS 11.5 to identify which balance strategy was predominantly utilized to control balance in the coronal and sagittal planes. A oneway ANOVA found a significant difference (p 0.009) between the groups for strategy utilised on the non-dominant leg in the sagittal plane. Fewer ACLR subjects (5%) were found to utilise ankle strategy compared to healthy controls (38%) on the non-dominant leg in the sagittal plane. Discussions and Conclusion: Ankle strategy predicts that the ankle movements alone act to accomplish balance control. This study found a greater proportion of the ACLR subjects utilised movements about the other joints to accomplish postural control, this may be explained as a compensatory strategy due to the ACL injury and subsequent reconstruction. This evidence may significantly influence the rehabilitation of clients after ACL reconstruction.
Analysis of postural sway to determine the balance strategy utilised in normal and chronic anterior cruciate ligament reconstructed subjects
A.M. Clifford 1, Rr. Woledge 1, H.M. Holder-Powell 2. 1Kingg' College
London, 2London South Bank University, UK Introduction: This study analyses postural sway to determine if
normal healthy and anterior cruciate ligament reconstructed (ACLR) subjects, predominantly control their balance solely about the ankle (ankle strategy) [1] or use movements about other joints.
[•
Joint angle monitoring in osteoarthritis patients using body-fixed sensors
H. Dejnabadi 1, B.M. Jolles 2, E. Casanova 3, R Fua 3, K. Aminian 1.
1Laboratory of Movement Analysis' and Measurement, Ecole Polytechnique Fdddrale de Lausanne (EPFL), 1015 Lausanne, Switzerland," e University of Lausanne (CHUV), H@ital Orthopddique de la Suisse Romantic, 1011, Lausanne, Switzerlan& SComputer Vision Laboratory, Ecole Polytechnique Fdddrale de Lausanne (EPFL), 1015 Lausanne, Switzerland Introduction: In gait and posture analysis, joint motion monitoring
is essential [1]. Body-fixed sensors can be used to obtain joint and segment angles; and to design ambulatory systems for long-term monitoring. This study presents a new method for real-time monitoring of lower limbs flexion-extension angles with osteoarthritis patients. Motion data were visualized as synthetic skeletons performing the same actions as the patients. Methods: Lower limbs movements during gait were captured by 5 modules of sensors attached on shanks, thighs, and sacrum. Each module consisted of a gyroscope and bi-axial accelerometers. Shank, thigh and knee angles were obtained by virtually shifting the sensors on the adjacent segments to their center of rotation, and applying biomechanical constraints. The gait of 10 healthy subjects and a reference motion capture system were used for validation. Afterwards, 30 patients with mobile-bearing or fixed-bearing knee prosthesis were monitored. Results: The results were very close to the reference system (error < 2°). The results of the patients as reported by temporal-spatial parameters showed a better improvement in fixed-bearing prostheses compared to the mobile-bearing ones. Moreover sensors signals allowed a visual comparison between baseline and different follow-up periods by superimposing time-normalized gait cycles obtained from image synthesis. Discussion and Conclusion: The proposed system ofers an accurate tool for joint motion monitoring. It quantified objectively gait improvement in term of knee prosthesis. Gait visualization provided a simple tool to monitor and display motion for long-term monitoring where camera based systems could not be used.
References [1] Aminian K, Trevisan C, Najafi B, Dejnabadi H, Frigo C, Pavan E, Telonio A, Cerati F, Marinoni EC, Robert Ph, Leyvraz PE Evaluation of an ambulatory system for gait analysis in hip
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Methods: 8 ACL patients walked and crossed obstacles of 3 heights (10, 20 and 30% leg lengths) before and 3 months after ACLR. Kinematic and kinetic data were measured using a motion analysis system (Vicon, Oxford Metrics, U.K.) and two force plates (AMTI, U.S.A.). An asymmetry index (AI, difference between sound and affected limbs/average of both limbs) was used to investigate the asymmetry of the joint kinematics and kinetics. Paired-t test was used for before after reconstruction comparisons (¢~ 0.05). Results: Significantly bigger AI values were found in the trailing knee crossing flexion angles and leading knee crossing flexor moments as well as the peak hip internal rotator moments of both limbs for all heights after ACLR. Discussion and Conclusion: The results suggest that ACLR did not help reduce the biomechanical asymmetry 3 months post-op. It may be associated with the persistent deficit of the muscle strength after surgery. Rehabilitation for a longer period of time may be needed to achieve better inter-limb coordination.
References [1] Kobayashi A., Higuchi H., Terauchi M., Kobayashi F., Kimura M. and Takagishi K. Muscle performance after anterior cruciate ligament reconstruction. International Orthopaedics 2004; 28: 48 51.
[•
References [1] Winter DA. Human balance and posture control during standing and walking. Gait Posture, 1995; 3:193 214.
Changes in postural control of patients with anterior cruciateligament dificiency
RW. Chiu 1, S.Y. Chen 1, H.C. Lin 1, H.C. Hsu 2. 1School of
Physical Therapy, China Medical University, China," 2Department of Orthopedics, China Medical University Hospital, China Introduction: Anterior cruciate ligament (ACL) not only plays
an important role on the passive stability of the knee joint but also provides proprioceptive feedback. ACL injury may cause the mechanical and neuromuscular changes of the knee joint and affect the balance function of these patients. The purpose of this study is to investigate the multi-sensory interactions on the postural control for the patients after the loss of ACL. Methods: Eight patients with unilateral ACL-deficient (ACLD) and eight matched control subjects were recruited. They were examined on PRO Balance Master with testing conditions including eyes open/close and fixed/swayed surface. Area, path, average velocity, and maximum velocity of center of pressure (COP) were obtained during the 20sec static stance. The percentage differences of sway (PDS) of these variables were calculated to reveal the quantitatively differences of vision and proprioception contribution to postural control between groups. Results: Compared with normal subjects, smaller PDSs for proprioception contribution in CoP area for vision and non-vision conditions while larger PDSs for visual contribution in CoP average velocity, and maximum velocity for stable surface condition were found (p < 0.05). Other variables demonstrated the similar trend but not reach statistical significance. Discussion and Conclusion: The findings in this study suggested that the ACLD patients increased their reliance on vision and decreased on proprioception. It implied that the ACL injury resulted in a re-distribution of the multi-sensory system for the postural control of the whole body.
[•
Methods: Three-dimensional movement, using the CODA motion analysis system, (Charnwood Dynamics UK) was obtained in 21 agematched healthy (9 males) and 18 ACLR subjects (10 males, mean time post surgery 6 yrs). During a 15 s, one-legged standing task postural sway was recorded, at 100Hz by two sensor units from 24 light emitting diodes placed on specific anatomical landmarks. Results: The data was exported and analysed in Mathcad 2001i and SPSS 11.5 to identify which balance strategy was predominantly utilized to control balance in the coronal and sagittal planes. A oneway ANOVA found a significant difference (p 0.009) between the groups for strategy utilised on the non-dominant leg in the sagittal plane. Fewer ACLR subjects (5%) were found to utilise ankle strategy compared to healthy controls (38%) on the non-dominant leg in the sagittal plane. Discussions and Conclusion: Ankle strategy predicts that the ankle movements alone act to accomplish balance control. This study found a greater proportion of the ACLR subjects utilised movements about the other joints to accomplish postural control, this may be explained as a compensatory strategy due to the ACL injury and subsequent reconstruction. This evidence may significantly influence the rehabilitation of clients after ACL reconstruction.
Analysis of postural sway to determine the balance strategy utilised in normal and chronic anterior cruciate ligament reconstructed subjects
A.M. Clifford 1, Rr. Woledge 1, H.M. Holder-Powell 2. 1Kingg' College
London, 2London South Bank University, UK Introduction: This study analyses postural sway to determine if
normal healthy and anterior cruciate ligament reconstructed (ACLR) subjects, predominantly control their balance solely about the ankle (ankle strategy) [1] or use movements about other joints.
[•
Joint angle monitoring in osteoarthritis patients using body-fixed sensors
H. Dejnabadi 1, B.M. Jolles 2, E. Casanova 3, R Fua 3, K. Aminian 1.
1Laboratory of Movement Analysis' and Measurement, Ecole Polytechnique Fdddrale de Lausanne (EPFL), 1015 Lausanne, Switzerland," e University of Lausanne (CHUV), H@ital Orthopddique de la Suisse Romantic, 1011, Lausanne, Switzerlan& SComputer Vision Laboratory, Ecole Polytechnique Fdddrale de Lausanne (EPFL), 1015 Lausanne, Switzerland Introduction: In gait and posture analysis, joint motion monitoring
is essential [1]. Body-fixed sensors can be used to obtain joint and segment angles; and to design ambulatory systems for long-term monitoring. This study presents a new method for real-time monitoring of lower limbs flexion-extension angles with osteoarthritis patients. Motion data were visualized as synthetic skeletons performing the same actions as the patients. Methods: Lower limbs movements during gait were captured by 5 modules of sensors attached on shanks, thighs, and sacrum. Each module consisted of a gyroscope and bi-axial accelerometers. Shank, thigh and knee angles were obtained by virtually shifting the sensors on the adjacent segments to their center of rotation, and applying biomechanical constraints. The gait of 10 healthy subjects and a reference motion capture system were used for validation. Afterwards, 30 patients with mobile-bearing or fixed-bearing knee prosthesis were monitored. Results: The results were very close to the reference system (error < 2°). The results of the patients as reported by temporal-spatial parameters showed a better improvement in fixed-bearing prostheses compared to the mobile-bearing ones. Moreover sensors signals allowed a visual comparison between baseline and different follow-up periods by superimposing time-normalized gait cycles obtained from image synthesis. Discussion and Conclusion: The proposed system ofers an accurate tool for joint motion monitoring. It quantified objectively gait improvement in term of knee prosthesis. Gait visualization provided a simple tool to monitor and display motion for long-term monitoring where camera based systems could not be used.
References [1] Aminian K, Trevisan C, Najafi B, Dejnabadi H, Frigo C, Pavan E, Telonio A, Cerati F, Marinoni EC, Robert Ph, Leyvraz PE Evaluation of an ambulatory system for gait analysis in hip