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Assessment of long-term development of muscle tendon length and velocity in children with cerebral palsy after hamstring lengthening
Gait & Posture 49S (2016) 232
Contents lists available at ScienceDirect
Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost
P88 presented in PS03: Poster teaser: CP
Assessment of long-term development of muscle tendon length and velocity in children with cerebral palsy after hamstring lengthening Firooz Salami *, Juila Brosa, Julia Wagner, Thomas Dreher, Sebastian Wolf, Mirjam Niklasch Heidelberg University Hospital, Heidelberg, Baden-Wu¨rttemberg, Germany
Introduction: Flexed knee gait is a common gait abnormality in children with cerebral palsy (CP). Hamstring lengthening is one possible treatment for patients with flexed knee gait. Patients with ‘‘short’’ and ‘‘slow’’ hamstrings are more likely to benefit of hamstring lengthening [1,2] than those with ‘‘normal’’ hamstring length and velocity. Long-term studies showed crucial results with significant deterioration of knee flexion, popliteal angle and an increase in pelvic tilt over the time [3]. To our knowledge, there is no long-term study assessing the changes in muscle tendon length (MTL) and velocity after hamstring lengthening. This assessment will help to identify those children, who will probably have a functional gain of long duration. Research question: How do MTL and velocity develop with time in children with CP after hamstring lengthening? Materials and methods: Five children with bilateral CP and flexed knee gait that underwent bilateral hamstring lengthening in the context of single event multi-level surgery (SEMLS) at an age of 10 2 years were retrospectively selected from our database. 3D gait analysis was performed preoperatively (E0), 1 year postoperatively (E1) and at least 5 years postoperatively (7 1 year) (E2). A customized generic OpenSim model was used to calculate the maximum velocity and MTL of Semimembranosus (semimem), semitendinosus (semiten) and biceps femoris long head (bifem) during one gait cycle. The MTL were normalized by leg length and the time was normalized by gait cycle duration. For each patient the average data of at least 3 gait cycles was used for assessment and
* Corresponding author. E-mail address: [email protected] (F. Salami). http://dx.doi.org/10.1016/j.gaitpost.2016.07.285 0966-6362/
statistical analysis. Kinematic data were calculated by the Plug-ingait model. Wilcoxon test was used to compare the mentioned parameters of all 10 included limbs between E0, E1 and E2 (p < 0.05). Results: Mean knee flexion in stance improved significantly from E0 to E1. The MTL did not change significantly, neither from E0 to E1, nor from E1 to E2. The maximum velocity for all muscles increased significantly from E0 to E1 and decreased from E1 to E2. Overall there was no significant difference between E0 and E2 for semimem and semiten and even a decrease of maximum bifem velocity form E0 to E2. Discussion: The missing change in MTL over time and of knee flexion from E1 to E2 is in contrast to previous literature [1] and probably has to be traced back to the small group of patients. Changes in maximum hamstring velocity seem to be more pronounced. A deterioration of hamstring velocity from E1 to E2 back to the preoperative setting appears probably due to the pubertal growth spurt and remaining spasticity. Further analysis with a larger group of patients will be needed to analyze the changes in velocity and MTL in correlation to changes in maximum and mean knee flexion and pelvic tilt over the time. References [1] Arnold. et al. J. Biomech. 2006;39(8):1498–506. [2] Schwartz. et al. J. Pediatr. Orthop. 2004;24(1):45–53. [3] Dreher. et al. J. Bone Jt. Surg. Am. 2012;94(2):121–30.
Contents lists available at ScienceDirect
Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost
P88 presented in PS03: Poster teaser: CP
Assessment of long-term development of muscle tendon length and velocity in children with cerebral palsy after hamstring lengthening Firooz Salami *, Juila Brosa, Julia Wagner, Thomas Dreher, Sebastian Wolf, Mirjam Niklasch Heidelberg University Hospital, Heidelberg, Baden-Wu¨rttemberg, Germany
Introduction: Flexed knee gait is a common gait abnormality in children with cerebral palsy (CP). Hamstring lengthening is one possible treatment for patients with flexed knee gait. Patients with ‘‘short’’ and ‘‘slow’’ hamstrings are more likely to benefit of hamstring lengthening [1,2] than those with ‘‘normal’’ hamstring length and velocity. Long-term studies showed crucial results with significant deterioration of knee flexion, popliteal angle and an increase in pelvic tilt over the time [3]. To our knowledge, there is no long-term study assessing the changes in muscle tendon length (MTL) and velocity after hamstring lengthening. This assessment will help to identify those children, who will probably have a functional gain of long duration. Research question: How do MTL and velocity develop with time in children with CP after hamstring lengthening? Materials and methods: Five children with bilateral CP and flexed knee gait that underwent bilateral hamstring lengthening in the context of single event multi-level surgery (SEMLS) at an age of 10 2 years were retrospectively selected from our database. 3D gait analysis was performed preoperatively (E0), 1 year postoperatively (E1) and at least 5 years postoperatively (7 1 year) (E2). A customized generic OpenSim model was used to calculate the maximum velocity and MTL of Semimembranosus (semimem), semitendinosus (semiten) and biceps femoris long head (bifem) during one gait cycle. The MTL were normalized by leg length and the time was normalized by gait cycle duration. For each patient the average data of at least 3 gait cycles was used for assessment and
* Corresponding author. E-mail address: [email protected] (F. Salami). http://dx.doi.org/10.1016/j.gaitpost.2016.07.285 0966-6362/
statistical analysis. Kinematic data were calculated by the Plug-ingait model. Wilcoxon test was used to compare the mentioned parameters of all 10 included limbs between E0, E1 and E2 (p < 0.05). Results: Mean knee flexion in stance improved significantly from E0 to E1. The MTL did not change significantly, neither from E0 to E1, nor from E1 to E2. The maximum velocity for all muscles increased significantly from E0 to E1 and decreased from E1 to E2. Overall there was no significant difference between E0 and E2 for semimem and semiten and even a decrease of maximum bifem velocity form E0 to E2. Discussion: The missing change in MTL over time and of knee flexion from E1 to E2 is in contrast to previous literature [1] and probably has to be traced back to the small group of patients. Changes in maximum hamstring velocity seem to be more pronounced. A deterioration of hamstring velocity from E1 to E2 back to the preoperative setting appears probably due to the pubertal growth spurt and remaining spasticity. Further analysis with a larger group of patients will be needed to analyze the changes in velocity and MTL in correlation to changes in maximum and mean knee flexion and pelvic tilt over the time. References [1] Arnold. et al. J. Biomech. 2006;39(8):1498–506. [2] Schwartz. et al. J. Pediatr. Orthop. 2004;24(1):45–53. [3] Dreher. et al. J. Bone Jt. Surg. Am. 2012;94(2):121–30.