AustPAR - Transtibial Amputee Gait Biomechanics

Amputee Gait Training

Biomechanics of Transtibial Amputee Gait

Transtibial gait biomechanics differ from those of non-amputees both in terms of kinematics and kinetics. Even where patterns may look similar, joint moments, power profiles, and velocity / timing of movements can differ. There are also differences that can be attributed to the type of prosthesis, particularly the foot.

This page provides a briefsummary of general differences, and does not describe differences due to different prosthetic components. References are supplied for further reading.Percentages for each part of the gait cycle are indicative only, as proportions of stance phase versus swing phase also differ between amputees and non-amputees.

Weight Acceptance
0 - 20%
Midstance
20 - 40%
Late Stance
40 - 60%
Early Swing
60 - 80%
Late Swing
80 - 100%

	Amputated Limb	Non-Amputees
Hip	Concentric hip extension throughout stance, mainly gluteus maximus, some hamstrings.	Concentric hip extension, mainly hamstrings, some gluteal activity.
Knee	Flexor moment, caused by increased hamstrings activity attempting to extend the hip, which pulls the knee back into extension	Extensor moment, as the knee flexes under load, decelerated by eccentric knee extensor activity
Ankle	Plantarflexion / dorsiflexion occurs within the prosthetic foot / ankle mechanism. Plantarflexion is reduced also due to a more flat-footed initial contact, due to a shorter step length	Plantarflexes immediately after heelstrike, under eccentric dorsiflexion control. Changes to eccentric plantarflexion control as the ankle dorsiflexes as the shank moves forward over the foot

	Amputated Limb	Non-Amputees
Hip	Variable power patterns, but still mainly concentric hip extensor activity.	Concentric hip extensor activity replaced by eccentric hip flexor activity as joint angle approaches & passes 00
Knee	Extends, but variable pattern. Join moment can still be flexor, as the hamstrings are still extending the hip, and the knee extends as the thigh rotates over the knee	Extends due to concentric extensor activity, to around 50
Ankle	Dorsiflexes with a passive internal dorsiflexor moment, but only 1/2 normal range, depending on type of foot	Continues to dorsiflex under eccentric plantarflexor control to around 8-100

	Amputated Limb	Non-Amputees
Hip	Variable power patterns, but still mainly concentric hip extensor activity. Range of hip extension is often reduced.	Extends under eccentric hip flexor control to about 540 through the stride, where activity switches to concentric flexor activity in preparation for swing
Knee	Knee can continue to extend, almost hyperextend as the thigh continues to rotate forward, to around 45% of stride. Flexion starts to occur, usually under control of eccentric quads, although there may be a contribution by hamstring activity which flexes the knee (while they continue to extend the hip), to make up for lost push off.	Starts t oflex from around 40-50% of stride, reaching 35-400 by toe off. The knee flexion is initiated by gastrocnemius activity, and controlled through eccentric knee extensor activity.
Ankle	Substantially reduced push off power (only a percentage of elastic energy stored in the foot / ankle during dorsiflexion is returned, depending on the type of foot). Range will generally return to neutral position, with no active planteraflexion.	Plantarflexes to 16-200, due to concentric triceps surae activity.

	Amputated Limb	Non-Amputees
Hip	Concentric hip flexor activity, sometimes greater than normal, to achieve 'pull off' to compensate for lack of push off.	Flexes to 190 by mid swing. The first part of swing includes some concentric hip flexor activity, but after the first 1/4 becomes eccentric extensor activity as the hip extensors decelerate the flexing thigh.
Knee	Continues to flex due to the combination of hip flexor and hamstring activity, but reduced total range.	Flexes to a peak of around 650 with knee flexion / heel rise limited by eccentric knee extensor activity. A small burst of concentric quads activity also helps to initiate extension, although much of the motion is pendular.
Ankle	Sits passively in neutral position.	Returns to neutral / slightly dorsiflexed position, through a small amount of concentric dorsiflexor activity.

	Amputated Limb	Non-Amputees
Hip	Begins to extend concentrically in preparation for heel contact, through concentric hip extensor activity.	Begins to extend concentrically in preparation for heel contact, through concentric hip extensor activity.
Knee	Eccentric hamstring activity is used as the shank moves forwards, although the amount required is less than normal due to a slower moving shank, lower prosthetic mass, and shorter stride length.	Eccentric hamstring activity decelerates the pendular shank motion, to around 20 off full extension. Knee extensors may become active in preparation for heel contact.
Ankle	Sits passively in neutral position.	Maintains plantargrade position until heelstrike.

References

Barnett C, Vanicek N, Polman R, Hancock A, Brown B, Smith L, Chetter I (2009). Kinematic gait adaptations in unilateral transtibial amputees during rehabilitation. Prosthetics and Orthotics International, 33, 2, 135-147.
Czerniecki JM, Gitter AJ (1996). Gait analysis in the amputee: Has it helped the amputee or contributed to the development of improved prosthetic components? Gait nad Posture, 4, 258-268.
Hermodsson Y, Ekdahl C, Persson BM, Roxendahl G (1984). Gait in male transtibial amputees: a comparative study with healthy subjects in relation to walking speed. Prosthetics & Orthotics International, 18, 68-77.
Hurley GRB, McKenney R, Robinson M, Zadravec, Pierrynowski MR (1990). The role of the contralateral limb in below-knee amputee gait. Prosthetics and Orthotics International, 14, 33-42.
Lemaire ED, Fisher FR, Robertson DGE (1993). Gait pattens of elderly men with trans-tibial amputations. Prosthetics & Orthotics International, 17, 27-37.
Moore S, Schurr K, Wales A, Mosely A, Herbert R (1993). Observation and analysis of hemiplegic gait: swing phase. Australian Journal of Physiotherapy, 39, 4, 271-278.
Mosely A, Wales A, Herbert R, Schurr K, Moore S (1993). Observation and analysis of hemiplegic gait: stance phase. Australian Journal of Physiotherapy, 39, 4, 259-267.
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Powers CM, Torburn L, Perry J, Ayyappa E (1994). Influence of prosthetic foot design on sound limb loading in adults with unilateral below-knee amputation. Archives of Physical Medicine & Rehabilitation, 75, 825-829.
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Vanicek N, Strike S, McNaughton L, Polman R (2009). Gait patterns in transtibial amputee fallers vs. non-fallers: Biomechanical differences during level walking. Gait and Posture, 29, 415–420
Winter DA (1983). Biomechanical motor patterns in normal walking. Journal of Motor Behaviour, 15, 4, 302-330.
Winter DA, Patla AE, Frank JS, Walt SE (1990). Biomechanical walking pattern changes in the fit and healthy elderly. Physical Therapy, 70, 6, 340-347.
Winter DA, Sienko SE (1988). Biomechanics of below-knee amputee gait. Journal of Biomechanics, 21, 5, 361-367.