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Role of gait characteristics on walking performance in knee osteoarthritis
Track 3. Musculoskeletal systems and Performance - Joint ISB/ESB Track
3.1. Joints - Knee
$71
(FDA). Instead of transforming a continuous time recording into a set of discrete variables, FDA techniques work with the whole function as single data, without loosening time information. Neither previous determination of singular events nor definition of discrete variables is necessary. We studied 21 patients before and after surgery and 10 healthy age-matched controls while performing different daily activities like stair-ascent and descent, sitting and arising from a chair. Patients underwent clinical assessment by applying the Knee Society Score. Full kinematics and kinetics of the knee joint were obtained through the use of stereophotogrammetry, force platforms and inverse dynamic analysis of the lower limb. From these data and applying FDA techniques, we have obtained time-movement patterns characterizing patients' knee biomechanics and have analyzed the differences between them and normal subjects.
Before surgery, the subjects took an average of 4580 gait cycles per day. At follow-up, the number of gait cycles per day increased to 5059 (+11%, n = 15) and 5441 (+15%, n = 10). 75.7% of the gait cycles were executed with a frequency between 1 and 20 gait cycles per minute. High frequencies (>40 gait cycles/minute) were performed in 6% of all gait cycles. Discussion: Six months after surgery, the knee patients appeared slightly more active (-2.0 million gait cycles per year) than patients with wellfunctioning hip replacements (-1.9 million gait cycles/y, [2]). However, the patients do not reach the level of healthy adults (-2.4 million gait cycles/y, own data). The time spent in locomotion is nearly identical to healthy adults, but patients walk with lower intensities than healthy adults. For wear testing of prostheses 2 million gait cycles should be considered as representative for overall loading during one year.
6994 Tu, 11:00-11:15 (P18) Role o f gait characteristics on walking performance in knee osteoarthritis M.R. Maly 1, P.A. Costigan 2, S.J. Olney 1. 1School ef Physical Therapy,
References [1] Pitta et al. Arch Phys Med Rehabil 2005; 86/10: 1979-85. [2] Silva et al. J Arthroplasty 2002; 17/6: 693-7.
The University of Western Ontario, London, Ontario, Canada, 2School of Physical & Health Education and 3School of Rehabilitation Therapy, Queen's University, Kingston, Ontario, Canada
4960 Tu, 11:30-11:45 (P18) Beneficial effect of single w h o l e body vibration training on sensorimotor control of the knee M. Melnyk 1, M. Faist 2, M. Hodapp 2, A. Gollhofer 1. 1Institute efSpert Science,
Little is known about the importance of gait characteristics to walking performance in knee OA. Research reveals that much of the variance in walking performance is explained by self-efficacy, or confidence to perform a task [1,2]. Our purpose was to explore the role of knee angles and moments on walking performance, over and above self-efficacy, in people with knee osteoarthritis (OA). Methods: Participants had radiographic medial knee OA (n =54, age 68.3±8.7 years). Three-dimensional gait data were collected at 100 Hz using an Optotrack and forceplate. We identified the mean peak and range values of knee angles and moments. The Six Minute Walk (SMW) recorded indoor walking distance. The Functional Self-Efficacy subscale (FSE) of the Arthritis SelfEfficacy scale assessed self-efficacy for physical tasks. Pearson Correlation Coefficients were calculated to explore relationships between gait characteristics and SMW. A step-wise linear regression was performed with the SMW as the dependent measure and 2 blocks of independent measures. Block 1 included FSE and block 2 included gait variables significantly correlated with SMW. Results and Discussion: Correlation coefficients (r) between gait variables and SMW ranged between 0.001 and 0.60. The peak extension angle and range of flexion/extension angle had significant relationships with the SMW. The peak extension angle and range of flexion/extension angle were moderately related (r =-0.58). The variance in SMW was explained by FSE (50%) and the range of knee flexion/extension angle (8%). Therefore, kinematic output from the motor control system was useful in understanding some variance in current performance. The knee adduction moment was unrelated to performance and does not explain current clinical status, based on performance in people with knee OA. Dynamic range of motion may be a proxy for knee function. Canadian Institutes for Health Research (#99034), Natural Sciences & Engineering Research Council, Toronto Rehabilitation Institute. References [1] Harrison. Phys-Ther. 2004; 84: 822431. [2] Maly. Phys-Ther. 2005; 85: 1318-1328.
4427 Tu, 11:15-11:30 (P18) Changes in locomotion performance after total knee arthroplasty (preliminary results) M. Brandes 1, M. Ringling 2, A. Hillmann 2, D. Rosenbaum 1. 1Motion Analysis
Lab, University Hospital Muenster, Germany, 2 Orthopaedic Department, Hospital Ingelstadt, Germany Introduction: Knee osteoarthritis is one of the most common reasons for walking impairments. If conservative treatment does not succeed, joint replacement is required. Mostly, the functional outcome after TKA is indirectly assessed with questionnaires. Thus, little is known about how the patients' activity level is affected by total knee arthroplasty. Methods: Physical activity of 40 subjects suffering from knee osteoarthritis is monitored before surgery and three, six and twelve months after knee replacement. Currently, six-month data is available for the first ten subjects (we expect >18 subjects in 06.2006). One device (DynaPort ADL-monitor) measured the time spent in locomotion, standing, sitting and lying for one day as well as the movement intensity [1]. The second device (Step-Activity-Monitor) collected the number of gait cycles for one week in 1-minute intervals [2]. Results: The time spent in locomotion improved from 7.6% (pre-op) to 9.0% (n = 14) and 11.1% (n = 10) three and six months post-op, respectively.
University of Freiburg, Freiburg, Germany, 2Department of Neurology, University of Freiburg, Freiburg, Germany The use of whole body vibration (WBV) as a training intervention in healthy and in recreational subjects has been increased in the last few years. However, the effect of a single WBV training on neuromuscular control of the knee joint is unclear. Therefore, in 13 subjects standing upright in 300 knee flexion the neuromuscular activation of the thigh muscles evoked by a posterior-anterior tibia translation was assessed. Measurements were performed before and after a single WBV training (frequency: 30 Hz, amplitude: 4 mm) consisting of 3 trails of 1 min each. Anterior tibia displacement was induced by an impact force of 285 N. Activity of the thigh muscles was recorded by surface electromyography (EMG) to assess latencies and motor activity (iEMG). Tibia translation was detected using two potentiometric position transducers applied on the tuberositas tibiae and on the patella. In all muscles a biphasic reflex pattern was found which was labelled as a short (SLR) and a medium latency response (MLR). For the hamstrings a SLR of 23.6±1.5 ms and a MLR of 38.2±1.4 ms were measured. The ventral thigh muscles showed a SLR of 29.1±2.1 ms and a MLR of 41.4±1.7ms. Whereas the latencies of all muscles were not significantly changed, the iEMG of the hamstring SLR was significantly increased after WBV (p =0.039). Surprisingly, only the iEMG of the vastus lateralis SLR as one of the three measured ventral thigh muscles showed a significant increase (p = 0.006). No significant differences were observed for the iEMGs of the MLR after WBV. The tibia translation significantly decreased from 4.8±0.8 mm to 3.6±0.8 mm after training (p = 0.031). Our results indicate that a single WBV training has a beneficial effect on the functional knee stability which seems to be related to a higher EMG activity of the hamstring SLR component. 7593 Tu, 11:45-12:00 (P18) Rotational knee laxity measurement device: reliability assessment in a cadaver model R.S. Costic, R. Allaire, K.M. Bell, V. Musahl, E. Frazier, T. Zantop, J.J. Irrgang, L.G. Gilbertson, EH. Fu. Department of Orthopaedic Surgery, University of
Pittsburgh, Pittsburgh, PA, USA Objective: Clinical assessment after injury to the knee is dependent on the experience of the examiner. Instrumentation can help to eliminate inexperience and has proven to be reliable in the past (KT-1000). However, no instrumented test is available to aid in the assessment of rotational knee laxity. The objective of this study was to evaluate the reliability of a rotational knee laxity measurement device in a cadaveric model. Methods: The rotational knee laxity measurement device is an Aircast Walker Brace instrumented with a 6-DOF universal force-moment sensor mounted to the sole, and a handle bar allowing the clinician to apply moments to the knee. A magnetic tracking system, Nest of Birds records the motion of the tibia with respect to the femur. Human cadaveric lower extremities (N = 4, Age 75±9 years) were transected mid-femur and fixed to a custom jig. The rotational knee laxity measurement device was secured to the leg and equal pressure (40 mm Hg) was applied to aircells for a secure fit. The knees were positioned at 0 °, 30 °, 600 and 900 of flexion and internal and external rotation moments were applied by two different examiners (5 trials at each angle). The rotations of the tibial sensor relative to the femoral sensor were recorded for 6 Nm of applied torque. For statistical analysis the single measures intraclass correlation coefficient (ICC) was used to gauge intra- and inter-observer reliability and was determined for internal and external rotation at each flexion angle.
3.1. Joints - Knee
$71
(FDA). Instead of transforming a continuous time recording into a set of discrete variables, FDA techniques work with the whole function as single data, without loosening time information. Neither previous determination of singular events nor definition of discrete variables is necessary. We studied 21 patients before and after surgery and 10 healthy age-matched controls while performing different daily activities like stair-ascent and descent, sitting and arising from a chair. Patients underwent clinical assessment by applying the Knee Society Score. Full kinematics and kinetics of the knee joint were obtained through the use of stereophotogrammetry, force platforms and inverse dynamic analysis of the lower limb. From these data and applying FDA techniques, we have obtained time-movement patterns characterizing patients' knee biomechanics and have analyzed the differences between them and normal subjects.
Before surgery, the subjects took an average of 4580 gait cycles per day. At follow-up, the number of gait cycles per day increased to 5059 (+11%, n = 15) and 5441 (+15%, n = 10). 75.7% of the gait cycles were executed with a frequency between 1 and 20 gait cycles per minute. High frequencies (>40 gait cycles/minute) were performed in 6% of all gait cycles. Discussion: Six months after surgery, the knee patients appeared slightly more active (-2.0 million gait cycles per year) than patients with wellfunctioning hip replacements (-1.9 million gait cycles/y, [2]). However, the patients do not reach the level of healthy adults (-2.4 million gait cycles/y, own data). The time spent in locomotion is nearly identical to healthy adults, but patients walk with lower intensities than healthy adults. For wear testing of prostheses 2 million gait cycles should be considered as representative for overall loading during one year.
6994 Tu, 11:00-11:15 (P18) Role o f gait characteristics on walking performance in knee osteoarthritis M.R. Maly 1, P.A. Costigan 2, S.J. Olney 1. 1School ef Physical Therapy,
References [1] Pitta et al. Arch Phys Med Rehabil 2005; 86/10: 1979-85. [2] Silva et al. J Arthroplasty 2002; 17/6: 693-7.
The University of Western Ontario, London, Ontario, Canada, 2School of Physical & Health Education and 3School of Rehabilitation Therapy, Queen's University, Kingston, Ontario, Canada
4960 Tu, 11:30-11:45 (P18) Beneficial effect of single w h o l e body vibration training on sensorimotor control of the knee M. Melnyk 1, M. Faist 2, M. Hodapp 2, A. Gollhofer 1. 1Institute efSpert Science,
Little is known about the importance of gait characteristics to walking performance in knee OA. Research reveals that much of the variance in walking performance is explained by self-efficacy, or confidence to perform a task [1,2]. Our purpose was to explore the role of knee angles and moments on walking performance, over and above self-efficacy, in people with knee osteoarthritis (OA). Methods: Participants had radiographic medial knee OA (n =54, age 68.3±8.7 years). Three-dimensional gait data were collected at 100 Hz using an Optotrack and forceplate. We identified the mean peak and range values of knee angles and moments. The Six Minute Walk (SMW) recorded indoor walking distance. The Functional Self-Efficacy subscale (FSE) of the Arthritis SelfEfficacy scale assessed self-efficacy for physical tasks. Pearson Correlation Coefficients were calculated to explore relationships between gait characteristics and SMW. A step-wise linear regression was performed with the SMW as the dependent measure and 2 blocks of independent measures. Block 1 included FSE and block 2 included gait variables significantly correlated with SMW. Results and Discussion: Correlation coefficients (r) between gait variables and SMW ranged between 0.001 and 0.60. The peak extension angle and range of flexion/extension angle had significant relationships with the SMW. The peak extension angle and range of flexion/extension angle were moderately related (r =-0.58). The variance in SMW was explained by FSE (50%) and the range of knee flexion/extension angle (8%). Therefore, kinematic output from the motor control system was useful in understanding some variance in current performance. The knee adduction moment was unrelated to performance and does not explain current clinical status, based on performance in people with knee OA. Dynamic range of motion may be a proxy for knee function. Canadian Institutes for Health Research (#99034), Natural Sciences & Engineering Research Council, Toronto Rehabilitation Institute. References [1] Harrison. Phys-Ther. 2004; 84: 822431. [2] Maly. Phys-Ther. 2005; 85: 1318-1328.
4427 Tu, 11:15-11:30 (P18) Changes in locomotion performance after total knee arthroplasty (preliminary results) M. Brandes 1, M. Ringling 2, A. Hillmann 2, D. Rosenbaum 1. 1Motion Analysis
Lab, University Hospital Muenster, Germany, 2 Orthopaedic Department, Hospital Ingelstadt, Germany Introduction: Knee osteoarthritis is one of the most common reasons for walking impairments. If conservative treatment does not succeed, joint replacement is required. Mostly, the functional outcome after TKA is indirectly assessed with questionnaires. Thus, little is known about how the patients' activity level is affected by total knee arthroplasty. Methods: Physical activity of 40 subjects suffering from knee osteoarthritis is monitored before surgery and three, six and twelve months after knee replacement. Currently, six-month data is available for the first ten subjects (we expect >18 subjects in 06.2006). One device (DynaPort ADL-monitor) measured the time spent in locomotion, standing, sitting and lying for one day as well as the movement intensity [1]. The second device (Step-Activity-Monitor) collected the number of gait cycles for one week in 1-minute intervals [2]. Results: The time spent in locomotion improved from 7.6% (pre-op) to 9.0% (n = 14) and 11.1% (n = 10) three and six months post-op, respectively.
University of Freiburg, Freiburg, Germany, 2Department of Neurology, University of Freiburg, Freiburg, Germany The use of whole body vibration (WBV) as a training intervention in healthy and in recreational subjects has been increased in the last few years. However, the effect of a single WBV training on neuromuscular control of the knee joint is unclear. Therefore, in 13 subjects standing upright in 300 knee flexion the neuromuscular activation of the thigh muscles evoked by a posterior-anterior tibia translation was assessed. Measurements were performed before and after a single WBV training (frequency: 30 Hz, amplitude: 4 mm) consisting of 3 trails of 1 min each. Anterior tibia displacement was induced by an impact force of 285 N. Activity of the thigh muscles was recorded by surface electromyography (EMG) to assess latencies and motor activity (iEMG). Tibia translation was detected using two potentiometric position transducers applied on the tuberositas tibiae and on the patella. In all muscles a biphasic reflex pattern was found which was labelled as a short (SLR) and a medium latency response (MLR). For the hamstrings a SLR of 23.6±1.5 ms and a MLR of 38.2±1.4 ms were measured. The ventral thigh muscles showed a SLR of 29.1±2.1 ms and a MLR of 41.4±1.7ms. Whereas the latencies of all muscles were not significantly changed, the iEMG of the hamstring SLR was significantly increased after WBV (p =0.039). Surprisingly, only the iEMG of the vastus lateralis SLR as one of the three measured ventral thigh muscles showed a significant increase (p = 0.006). No significant differences were observed for the iEMGs of the MLR after WBV. The tibia translation significantly decreased from 4.8±0.8 mm to 3.6±0.8 mm after training (p = 0.031). Our results indicate that a single WBV training has a beneficial effect on the functional knee stability which seems to be related to a higher EMG activity of the hamstring SLR component. 7593 Tu, 11:45-12:00 (P18) Rotational knee laxity measurement device: reliability assessment in a cadaver model R.S. Costic, R. Allaire, K.M. Bell, V. Musahl, E. Frazier, T. Zantop, J.J. Irrgang, L.G. Gilbertson, EH. Fu. Department of Orthopaedic Surgery, University of
Pittsburgh, Pittsburgh, PA, USA Objective: Clinical assessment after injury to the knee is dependent on the experience of the examiner. Instrumentation can help to eliminate inexperience and has proven to be reliable in the past (KT-1000). However, no instrumented test is available to aid in the assessment of rotational knee laxity. The objective of this study was to evaluate the reliability of a rotational knee laxity measurement device in a cadaveric model. Methods: The rotational knee laxity measurement device is an Aircast Walker Brace instrumented with a 6-DOF universal force-moment sensor mounted to the sole, and a handle bar allowing the clinician to apply moments to the knee. A magnetic tracking system, Nest of Birds records the motion of the tibia with respect to the femur. Human cadaveric lower extremities (N = 4, Age 75±9 years) were transected mid-femur and fixed to a custom jig. The rotational knee laxity measurement device was secured to the leg and equal pressure (40 mm Hg) was applied to aircells for a secure fit. The knees were positioned at 0 °, 30 °, 600 and 900 of flexion and internal and external rotation moments were applied by two different examiners (5 trials at each angle). The rotations of the tibial sensor relative to the femoral sensor were recorded for 6 Nm of applied torque. For statistical analysis the single measures intraclass correlation coefficient (ICC) was used to gauge intra- and inter-observer reliability and was determined for internal and external rotation at each flexion angle.