The goal of this work is to establish a scientific basis for treating stiff-knee gait in persons with cerebral palsy. Stiff-knee gait is a prevalent, debilitating movement abnormality that is characterized by inadequate knee flexion during the swing phase. The reputed cause of stiff-knee gait is over-activity of the rectus femoris muscle; hence, individuals with stiff-knee gait frequently undergo rectus femoris transfer surgery. Unfortunately the outcomes of these procedures are inconsistent. The PIs hypothesize that several factors, in addition to over-activity of the rectus femoris, contribute to the diminished knee flexion that is commonly observed. If these factors were identified, and if methods were developed to determine which of these factors contribute to an individual's abnormal gait, then treatments for stiff-knee gait could be designed more effectively. ? ? Muscle-actuated, forward dynamic simulations will be created that reveal the causes of diminished knee flexion in subjects with stiff-knee gait and explain the functional consequences of rectus femoris transfer surgery.
Aim 1 will identify the factors that can cause stiff-knee gait, and will generate an algorithm to uncover which of these factors contribute to diminished knee flexion in patients with a range of neuromusculoskeletal impairments.
Aim 2 will determine why some individuals walk with diminished swing-phase knee flexion following surgeries performed to correct other aspects of their abnormal gait.
Aim 3 will examine the potential of the rectus femoris to augment knee flexion after tendon transfer surgery.
Aim 4 will test the validity and utility of the simulation-based analyses for guiding treatment decisions by determining whether patients have better outcomes when interventions are performed that address the biomechanical causes of their stiff-knee gait, as determined using the simulations. This work will provide new guidelines deciding which patients should undergo rectus femoris transfer surgery, and which patients are likely to benefit more from other treatments, such as bracing, strengthening exercises, injections of neuromuscular blocking agents, or other surgeries. ? ? The success of this project will result in the first (rigorously tested) simulation-based system to aid treatment planning for stiff-knee gait, and will hopefully result in better, more predictable surgical outcomes. Although multi-joint movement abnormalities such as stiff-knee gait are exceptionally complex, the development of dynamic simulations that elucidate the causes of patients' movement abnormalities is an important and necessary next step toward designing more effective treatments. ? ?

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
1R01HD046814-01
Application #
6771458
Study Section
Special Emphasis Panel (ZHD1-RRG-K (11))
Program Officer
Quatrano, Louis A
Project Start
2004-06-01
Project End
2008-05-31
Budget Start
2004-06-01
Budget End
2005-05-31
Support Year
1
Fiscal Year
2004
Total Cost
$352,535
Indirect Cost
Name
Stanford University
Department
Biomedical Engineering
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Seth, Ajay; Hicks, Jennifer L; Uchida, Thomas K et al. (2018) OpenSim: Simulating musculoskeletal dynamics and neuromuscular control to study human and animal movement. PLoS Comput Biol 14:e1006223
Draper, Christine E; Quon, Andrew; Fredericson, Michael et al. (2012) Comparison of MRI and ยน?F-NaF PET/CT in patients with patellofemoral pain. J Magn Reson Imaging 36:928-32
Draper, Christine E; Fredericson, Michael; Gold, Garry E et al. (2012) Patients with patellofemoral pain exhibit elevated bone metabolic activity at the patellofemoral joint. J Orthop Res 30:209-13
Hicks, Jennifer L; Delp, Scott L; Schwartz, Michael H (2011) Can biomechanical variables predict improvement in crouch gait? Gait Posture 34:197-201
Draper, Christine E; Besier, Thor F; Fredericson, Michael et al. (2011) Differences in patellofemoral kinematics between weight-bearing and non-weight-bearing conditions in patients with patellofemoral pain. J Orthop Res 29:312-7
Fox, Melanie D; Delp, Scott L (2010) Contributions of muscles and passive dynamics to swing initiation over a range of walking speeds. J Biomech 43:1450-5
Hamner, Samuel R; Seth, Ajay; Delp, Scott L (2010) Muscle contributions to propulsion and support during running. J Biomech 43:2709-16
Agarwal-Harding, Kiran J; Schwartz, Michael H; Delp, Scott L (2010) Variation of hamstrings lengths and velocities with walking speed. J Biomech 43:1522-6
Steele, Katherine M; Seth, Ajay; Hicks, Jennifer L et al. (2010) Muscle contributions to support and progression during single-limb stance in crouch gait. J Biomech 43:2099-105
Fox, Melanie D; Reinbolt, Jeffrey A; Ounpuu, Sylvia et al. (2009) Mechanisms of improved knee flexion after rectus femoris transfer surgery. J Biomech 42:614-9

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