Department of Podiatry

Clinical Gait Analysis

Gait analysis - why bother ? - static measurements may be invalid indicators of dynamic function - 'the only way to assess a dynamic structure is dynamically' - see Knutzen and Price (1994), Hamill et al (1989) - can be used prior to static assessment to 'focus' on particular areas of interest or - requires a lot of practice - movements take place in a fraction of a second

Gait analysis - how

- systematic approach
- head to toe
- check for asymmetries

Treadmills

- useful adjunct to overground walking evaluation
- benefits: continuous, videotape: replay, frame-by-frame, can also observe sagittal plane, good for patient education

Problems with treadmills
- expense
- safety
- may not be appropriate for patients with balance difficulties / children
- gait alterations: inconsistent: may over-predict or under-predict overground walking style, flat-footed weight acceptance, forward trunk lean, medial roll-off, rather than active propulsion through 1st MPJ, shorter stride length, higher stride rate
- may not be a valid indicator of normal walking

Things to look for

- need to remember normal timing of events
- look for asymmetries / abnormal degrees of motion
- try to concentrate on one aspect at a time
- categorise rather than quantify, and only record if clearly significant
- specific pathomechanical considerations: abductory twist, extensor substitution, flexor stabilisation, angle of gait

1. Abductory twist
During midstance, the pelvis begins to externally rotate from its most internal position. With this external rotation, the foot should normally be undergoing supination in preparation for propulsion, leading to external tibial rotation. However, if in midstance the foot remains pronated or continues to pronate, the tibia is held in an internally rotated position. The external rotation of the femur places a large torque on the internally rotated tibia, so as the heel leaves the ground the pronated STJ cannot hold the tibia in internal rotation any longer and an external rotatory twist occurs at the metatarsal heads (forefoot abducts, heel adducts). An abductory twist can be observed from posterior (as evidenced by heel adduction following heel lift) and anterior (abductory twist around first MPJ as patient approaches you).

2. 'Too many toes' sign
The normal angle of gait is approximately 5-10 degress of out-toeing, so when viewing the foot from posterior you should be able to see 1.5 to 2 toes lateral to the heel. If you can observe more than 1-2 toes, a 'too many toes' sign exists which indicates either a larger than normal angle of gait or excessive forefoot abduction associated with excessive STJ pronation. Excessive forefoot abduction can be differentially diagnosed from a large AoG as with a large AoG the lateral border of the foot will be straight, whereas with forefoot abduction it will be concave.

3. Resupination
The STJ should begin to supinate in late midstance in preparation for propulsion. This is evidenced by heel inversion, external tibial rotation (probably the easiest to observe) and elevation of the medial longitudinal arch. If these features are not observed or occur later than the end of midstance, the foot has remained in a pronated position for longer than is normal. A lack of resupination often leads to a medial roll-off during propulsion and may be evidenced by HK on the medial aspect of the first MPJ and IPJ.

Summary

- gait analysis is complex, highly subjective and only moderately reliable
- 'even the most experienced practitioner will have difficulty avoiding seeing what he wants to see'
- however, reliability improves with experience and static measurements alone are poor predictors of dynamic function
- gait analysis is a useful adjunct to clinical measurement

References

Hamill J, Bates BT, Knutzen KM, Kirkpatrick (1989) Relationship between selected static and dynamic measures. Clinical Biomechanics 4(4): 217-225.

Knutzen KM, Price A (1994) Lower extremity static and dynamic relationships with rearfoot motion in gait. Journal of the American Podiatric Medical Association 84(4): 171-180.

Michaud TC (1993) Foot orthoses and other forms of conservative foot care. Williams and Wilkins, Baltimore, P.188-191.


NB: Walking man graphic taken from the clinical gait analysis web page of Chris Kirtley (By the way, Chris Kirley's site on CGA is definitely worth checking out).

Links to relevant web pages

Three dimensional motion analysis of the foot and ankle

Content Approved by: Head of Podiatry
Page maintained by: Podiatry Webmaster
Last Updated: August 14th, 2003