UF_Lecture_5_Clinical_Measures

UF_Lecture_5_Clinical_Measures - Lecture 5 Clinically...

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Unformatted text preview: Lecture 5 Clinically Useful Locomotion Measures EML 5595 Mechanics of the Human Locomotor System Outline Definition of a clinically useful locomotion measure Journal article review Lin et al. (2006) ( ) Journal article review Wang et al. (1990) Caution on the application of clinically useful locomotion measures Definition A clinically useful locomotion measure is a quantity that "predict[s] a different outcome than would be predicted without the measure" or that p "change[s] the clinician's choice of treatment." - Brand (2001) "Locomotion Analysis" Definition One could also say that a clinically useful locomotion measure is a quantity that could be used to determine the best way to design a treatment. A clinically useful locomotion measure can therefore be viewed as a "target" that the g clinician wants to "hit" with the treatment. Ideally this target can be predicted with a neuromusculoskeletal model for different treatment designs under consideration. Treatment design changes from general and subjective t patient-specific and objective. bj ti to patientti t ifi d bj ti Clinically Useful Locomotion y Measures for Stroke Question: In the context of walking, what is the "target" that the clinician wants to "hit" when treating patients who have had a stroke? Answer: Normal gait speed and normal gait pattern (meaning symmetric motion). Clinically Useful Locomotion y Measures for Stroke Question: What are the clinical factors that may influence the ability to achieve a normal gait speed and a normal gait pattern? Answer: Muscle weakness Uncoordinated muscle activity S ti muscle activity Spastic l ti it Sensory or visual deficits Soft-tissue tightness Soft- Clinically Useful Locomotion y Measures for Stroke Hypothesis: Weakness and spastic activity of ankle muscles is significantly associate with decreased gait speed and increased gait asymmetry. Approach: Perform gait experiments using a GAITRite system on 68 patients who have had a stroke, along with ankle strength measurements on t k l ith kl t th t a hand-held dynamometer and gastrocnemius handEMG measurements using surface electrodes. Clinically Useful Locomotion y Measures for Stroke Clinical measurements: Velocity (cm/s) C d Cadence ( t (steps/min) / i ) Stride length (cm) Step width (cm) Step length (cm) (both) Temporal asymmetry = 1 T l 1- Cycle time Si l -lleg support time (s) (both) SingleSingle t ti ( ) (b th) Double leg support time (s) Temporal asymmetry Spatial asymmetry single support time (affected) single support time (unaffected step length (affected) step length (unaffected t l th ( ff t d Spatial asymmetry = 1p y y Clinically Useful Locomotion y Measures for Stroke Additional measurements: Plantarflexor strength (%) (both) Dorsiflexor strength (%) (b th) D ifl t th (both) Spasticity index (%/cm s-1) Passive stiffness (deg) (both) Position error (deg) Spasticity index = Gastrocnemius EMG(%) Gastrocnemius lengthening velocity(cm / s) Clinically Useful Locomotion y Measures for Stroke Key findings from step-wise regression: step Gait velocity mainly affected by dorsiflexor strength (R2 =.30) g (R ) Temporal asymmetry mainly affected by dorsiflexor strength (R2 =.38) (R S ti l asymmetry mainly affected by Spatial t i l ff t d b spasticity index (R2 =.53) (R Question: How could you use this information to predict how different treatment approaches might improve gait speed and asymmetry for patients who have had a stroke? Clinically Useful Locomotion y Measures for Knee Osteoarthritis Question: In the context of walking, what is the "target" that the clinician wants to "hit" when treating patients who have knee osteoarthritis? Answer: The peak external knee adduction moment, which has also been correlated with pain and rate of disease progression in other studies. Clinically Useful Locomotion y Measures for Knee Osteoarthritis Question: What are the clinical factors that may influence the ability to achieve a normal peak knee adduction moment? Answer: Static leg alignment (and HTO surgery) Dynamic factors (alignment?) T out angle Toe t l Footwear Clinically Useful Locomotion y Measures for Knee Osteoarthritis Hypothesis: Patients with lower pre-surgery knee preadduction moments have less recurrence of varus deformity and better clinical outcome than do those with higher pre-surgery knee adduction moments. premoments. Approach: Perform gait experiments using videovideobased motion analysis on 24 patients who had high tibial osteotomy th tibi l t t three to nine years earlier. t i li Clinically Useful Locomotion y Measures for Knee Osteoarthritis Clinically Useful Locomotion y Measures for Knee Osteoarthritis Key findings: The low pre-surgery knee adduction premoment group has less recurrence of varus g p deformity and better clinical outcome. Toeing out and shortening the stride length were associated with lower peak knee adduction moments. Question: Should we expect any gait alteration that lowers the peak knee adduction moment to produce lower medial compartment knee contact force? Clinically Useful Locomotion y Measures for Knee Osteoarthritis Walker et al. (2010) J Orthop Res Clinically Useful Locomotion y Measures for Knee Osteoarthritis Caution when applying a clinically useful locomotion measure for one situation to a related situation. Walker et al. (2010) J Orthop Res For Next Time Finishing Fi i hi working th ki through O h OpenSim T t i l 3 Si Tutorial Download and read Pandy et al. (1990) J Biomechanics 23: 1185-1198. 1185Download and read instructions for Simulation Lab 1 ...
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This note was uploaded on 02/15/2012 for the course EML 5595 taught by Professor Staff during the Spring '08 term at University of Florida.

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