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Department
of Podiatry
Visual
Gait Analysis
Why
perform a biomechanical assessment?
‘No other group of health care professionals ..spends as much time
in their professional education learning “biomechanics” C.C.
Southerland, Jr.
‘Clinical gait evaluation is a fundamental skill for podiatric physicians’
Gait
analysis
Gait analysis/Dynamic assessment
- forms part of the overall assessment of the locomotor system
- ‘essence’ of the overall assessment
- focuses on the position and alignment of the body and the relationship
of the foot to the ground during gait
- Involves discriminating as to whether they are normal or abnormal
- visual versus computerised gait analysis
Other analyses of the locomotor system
- Non-WBing - focus on joint motion and alignment as well as muscle strength
Eg Forefoot to rearfoot relationship
- Static WBing - focuses on the position and alignment of the body and
the relationship of the foot to the ground during stance
Eg Foot Posture Index
The
walkway
Requirements
- Hard surface, straight & level
- good lighting
- minimum length 8-12 m
- the ability to view in both the frontal and sagittal planes
- minimum width 1.1 m
- Can use treadmill plus/minus camera
The
patient
- Shod & unshod with patellae visible
- Clothing should be worn to make observations easy and reliable
- leotards/shorts with t-shirt
- Needs to walk back and forth several times looking straight ahead and
letting arms swing naturally
Patient walking speed
- Many parameters of gait vary with walking speed (eg kinematics)
- Controlling cadence reduces variability but may reduce the validity
of the observations
- Use own judgement
eg athlete versus non-athlete
The
analysis
- Requires a systematic and logical approach observing the gait patterns
patient presents
- Does it represent normality?
- Reliant on skill of clinician
- Anatomic, theoretical (eg kinetics/kinematics) and clinical biomechanics
Components
- problem identification
- cause identification and subsequent treatment
Problem identification
- Initially - gross review of gait to sense the ‘flow of action’
- Followed by specific analysis in the frontal & sagittal planes to
identify significant gait deviations
- May be observing effects not causes
- ‘observed gait pattern is not the direct result of a pathological
process, but the net result of a pathological process and the patient’s
attempt to compensate for it’ (Whittle, 1996)
What to look for:
- Observe one segment at a time comparing R & L sides for symmetry
of timing and joint positions
- start at the foot, and progressing sequentially upward (or vice-versa)
- Separately observe events occurring during each of the periods of gait
(eg contact, midstance, propulsion)
- A bisection of the posterior calcaneus and posterior aspect of leg is
often helpful to aide visualisation
- A mark on the medial side of the navicular is also helpful
Some anatomical and functional features to observe for (frontal):
Some anatomical
and functional features to observe for (sagittal):
Angle
of gait
- angle formed between the line of progression and a longitudinal bisection
of the foot (bisection from heel to 2nd met/1st ID space)
- Normal value = ~7°
- May be abducted/external or adducted/internal
Base of gait
- horizontal distance from one heel-strike to the next heel-strike (bisection
of posterior heel)
- Normal value = ~ 90mm
- May be narrow or wide
Rearfoot motion (STJ)
- STJ motion - pronation and supination observed as eversion and inversion
in frontal plane (from posterior view)
- STJn/NCSP is when STJ is neither pronated nor supinatedPronation during
contact period (4-6°), then resupinates during midstance and propulsion
(4-6°).
- Visualised as slight eversion then inversion of the calcaneus under
the tibia
Midtarsal joint motion
- Navicular positioned at apex of MLA
- STJ pronation decreases MLA (navicular) height
- STJ supination increases MLA (navicular) height
T- hus, MLA/navicular height should decrease during contact period then
rise from midstance to propulsion
Gait analysis: cause identification
- Involves drawing together information obtained from:
Complete history and physical examination
Gait analysis
Possible causes of gait abnormalities
impaired motor control/muscle strength or proprioception
pain
Abnormal joint ROM and/or alignment
Summary
- Biomechanical assessment
- history/physical/locomotor system assessment
- visual gait analysis
- walkway & patient set-up
- problem solving approach
- problem and cause identification
- functional features to observe for
- Angle & base of gait, rearfoot & midfoot motion
- A SKILL REQUIRING MUCH PRACTICE
References:
Gait
Analysis: An introduction. Whittle, M. 1996: pp. 48-57, 130-36.
Observation of human gait. Parts 1, 2, & 3. Bundoora AV video. Call
no. 612.76 014
Valmassy Chapter 7, pp. 149-161. Gait evaluation in clinical biomechanics,
by C.C. Southerland, Jr
.
Assessment of the lower limb Chapter 8, pp.139-154. D.R. Tollafield &
L. Merriman
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