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Assessment of net knee moment-angle characteristics by instrumented hand-held dynamometry in children with spastic cerebral palsy and typically developing children.

Haberfehlner H, Maas H, Harlaar J, Newsum IE, Becher JG, Buizer AI, Jaspers RT - J Neuroeng Rehabil (2015)

Bottom Line: The slope at 4 Nm of the knee moment-angle curve in SCP children was significantly higher than that in typically developing children.The presented knee hand-held dynamometry allows assessment of net knee flexion moment-knee angle characteristics in typically developing and SCP children and can be used to identify clinically relevant changes as a result of treatment.Overall stiffness of structures that contribute to the net knee flexion moment at the knee (i.e. muscles, tendons, ligaments) is elevated in SCP children.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorststraat 9, 1081, BT, Amsterdam, The Netherlands. h.haberfehlner@vu.nl.

ABSTRACT

Background: The limited range of motion during walking in children with spastic cerebral palsy (SCP) may be the result of altered mechanical characteristics of muscles and connective tissues around the knee joint. Measurement of static net knee moment-angle relation will provide insights into these alterations, for which instrumented hand-held dynamometry may be applied. The aims of this study were: (1) to test the measurement error of the estimated net knee moment-angle characteristics, (2) to determine the correlation between knee extension angle measurement at a standardized knee moment and popliteal angle from common physical examination and (3) to compare net knee moment-angle characteristics in SCP versus typically developing children.

Methods: With the child lying in sideward position, the knee was extended by moving the lower leg by a hand-held force transducer on a low friction cart. Force data were collected for a range of knee angles. Data were excluded when activity (EMG) levels of knee extensor and flexor muscles exceeded the EMG level during rest by more than two standard deviations. The net knee flexion moments were calculated from recorded force data and measured moment arm. Reliability for knee angles corresponding with 0.5, 1, 2, 3, and 4 Nm knee net flexion moments was assessed by standard error of measurements (SEM) and smallest detectable difference (SDD).

Results: For between day comparison, SEMs were about 5° and SDDs were below 14° for knee angles at 1-4 Nm net knee flexion moments. In SCP children, the knee angle measured at 4 Nm knee flexion moment was not related to the popliteal angle (r = 0.52). The slope at 4 Nm of the knee moment-angle curve in SCP children was significantly higher than that in typically developing children.

Conclusions: The presented knee hand-held dynamometry allows assessment of net knee flexion moment-knee angle characteristics in typically developing and SCP children and can be used to identify clinically relevant changes as a result of treatment. Overall stiffness of structures that contribute to the net knee flexion moment at the knee (i.e. muscles, tendons, ligaments) is elevated in SCP children.

No MeSH data available.


Related in: MedlinePlus

Top view of hand-held dynamometry measurement setup. Children were positioned on their left side on a treatment table, with the hip of the measured (right) leg at 70° flexion (a). Pelvis and upper leg were tightly secured – the upper leg with a bandage (b) and the pelvis with an adjustable frame (c1) and foam blocks on both sides of the trunk (c2). The lower leg was positioned on a low-friction movable plate (d). The lower leg was manually moved with a hand-held force transducer (e) through its range of motion with stops for 10 s every 5°
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Fig1: Top view of hand-held dynamometry measurement setup. Children were positioned on their left side on a treatment table, with the hip of the measured (right) leg at 70° flexion (a). Pelvis and upper leg were tightly secured – the upper leg with a bandage (b) and the pelvis with an adjustable frame (c1) and foam blocks on both sides of the trunk (c2). The lower leg was positioned on a low-friction movable plate (d). The lower leg was manually moved with a hand-held force transducer (e) through its range of motion with stops for 10 s every 5°

Mentions: Subjects were lying on their left side on a comfortable examination table. The right leg was measured with the right hip positioned in 70° flexion. The left hip was put in a comfortable slightly flexed position (20°-40°). To prevent pelvic tilt and hip movement during measurements, pelvis and upper leg were tightly secured to the setup - the pelvis with an adjustable frame and foam blocks on both sides of the trunk and the upper leg with a bandage. The right lower leg was resting on a low friction cart (appropriately fastened) with the ankle in plantar flexion (about -20°) to minimize effects of gastrocnemius on knee moment (Fig. 1). This setup was designed such that in future experiments simultaneous ultrasound imaging of medial hamstrings would be possible.Fig. 1


Assessment of net knee moment-angle characteristics by instrumented hand-held dynamometry in children with spastic cerebral palsy and typically developing children.

Haberfehlner H, Maas H, Harlaar J, Newsum IE, Becher JG, Buizer AI, Jaspers RT - J Neuroeng Rehabil (2015)

Top view of hand-held dynamometry measurement setup. Children were positioned on their left side on a treatment table, with the hip of the measured (right) leg at 70° flexion (a). Pelvis and upper leg were tightly secured – the upper leg with a bandage (b) and the pelvis with an adjustable frame (c1) and foam blocks on both sides of the trunk (c2). The lower leg was positioned on a low-friction movable plate (d). The lower leg was manually moved with a hand-held force transducer (e) through its range of motion with stops for 10 s every 5°
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4536590&req=5

Fig1: Top view of hand-held dynamometry measurement setup. Children were positioned on their left side on a treatment table, with the hip of the measured (right) leg at 70° flexion (a). Pelvis and upper leg were tightly secured – the upper leg with a bandage (b) and the pelvis with an adjustable frame (c1) and foam blocks on both sides of the trunk (c2). The lower leg was positioned on a low-friction movable plate (d). The lower leg was manually moved with a hand-held force transducer (e) through its range of motion with stops for 10 s every 5°
Mentions: Subjects were lying on their left side on a comfortable examination table. The right leg was measured with the right hip positioned in 70° flexion. The left hip was put in a comfortable slightly flexed position (20°-40°). To prevent pelvic tilt and hip movement during measurements, pelvis and upper leg were tightly secured to the setup - the pelvis with an adjustable frame and foam blocks on both sides of the trunk and the upper leg with a bandage. The right lower leg was resting on a low friction cart (appropriately fastened) with the ankle in plantar flexion (about -20°) to minimize effects of gastrocnemius on knee moment (Fig. 1). This setup was designed such that in future experiments simultaneous ultrasound imaging of medial hamstrings would be possible.Fig. 1

Bottom Line: The slope at 4 Nm of the knee moment-angle curve in SCP children was significantly higher than that in typically developing children.The presented knee hand-held dynamometry allows assessment of net knee flexion moment-knee angle characteristics in typically developing and SCP children and can be used to identify clinically relevant changes as a result of treatment.Overall stiffness of structures that contribute to the net knee flexion moment at the knee (i.e. muscles, tendons, ligaments) is elevated in SCP children.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorststraat 9, 1081, BT, Amsterdam, The Netherlands. h.haberfehlner@vu.nl.

ABSTRACT

Background: The limited range of motion during walking in children with spastic cerebral palsy (SCP) may be the result of altered mechanical characteristics of muscles and connective tissues around the knee joint. Measurement of static net knee moment-angle relation will provide insights into these alterations, for which instrumented hand-held dynamometry may be applied. The aims of this study were: (1) to test the measurement error of the estimated net knee moment-angle characteristics, (2) to determine the correlation between knee extension angle measurement at a standardized knee moment and popliteal angle from common physical examination and (3) to compare net knee moment-angle characteristics in SCP versus typically developing children.

Methods: With the child lying in sideward position, the knee was extended by moving the lower leg by a hand-held force transducer on a low friction cart. Force data were collected for a range of knee angles. Data were excluded when activity (EMG) levels of knee extensor and flexor muscles exceeded the EMG level during rest by more than two standard deviations. The net knee flexion moments were calculated from recorded force data and measured moment arm. Reliability for knee angles corresponding with 0.5, 1, 2, 3, and 4 Nm knee net flexion moments was assessed by standard error of measurements (SEM) and smallest detectable difference (SDD).

Results: For between day comparison, SEMs were about 5° and SDDs were below 14° for knee angles at 1-4 Nm net knee flexion moments. In SCP children, the knee angle measured at 4 Nm knee flexion moment was not related to the popliteal angle (r = 0.52). The slope at 4 Nm of the knee moment-angle curve in SCP children was significantly higher than that in typically developing children.

Conclusions: The presented knee hand-held dynamometry allows assessment of net knee flexion moment-knee angle characteristics in typically developing and SCP children and can be used to identify clinically relevant changes as a result of treatment. Overall stiffness of structures that contribute to the net knee flexion moment at the knee (i.e. muscles, tendons, ligaments) is elevated in SCP children.

No MeSH data available.


Related in: MedlinePlus