TF - Gait Deviations Lecture

Functional Lengthening

During Stance Phase

• hip extension, knee extension, plantar flexion

Functional Shortening

During Swing Phase

• hip flexion, knee flexion, dorsiflexion

Leg Length Discrepancies

One leg is longer than the other leg, can be the cause to many of the following gait deviations.

Potential Causes

• Pseudo-LLD (inability to functionally shorten the prosthesis)

• incorrect alignment/measurement

• poor suspension

• incorrect resistance to knee flexion

• incorrectly adjusted extension bias

Knee Instability

During Initial Contact (Heel Strike)

Characterized by a ‘shaking’ at the knee during initial stance phase. Hip extensors fire then relax and then fire again due to the instability.

Potential causes

• knee set too far anterior (relative to socket)

• excessive resistance to PF

• increased shoe heel height (anterior leaning pylon)

• insufficient initial socket flexion

• weak hip extensors

Abducted Gait

Throughout Swing and Stance

Characterized by patient demonstrating a laterally deviated prosthesis throughout swing and stance phases of gait.

Potential Causes

• pressure on the pubic ramus

• pain at the distal lateral femur

• inadequate support on the femur from the lateral wall

• prosthesis too long

• excessive socket abduction

• weak contracted abductors

• lack of balance or insecurity

Lateral Trunk Bending

TWO KINDS - Towards the sound side and towards the prosthetic side

Midstance

Characterized by the patient’s shoulders moving outside the base of support while the pelvis maintains its position over the base of support.

Toward the Sound Side Potential Causes

• excessive foot outset

• wide ML dimension of socket

• weak hip abductors

• poor balance

Towards the Prosthetic Side Potential Causes

• prosthesis too short

• excessive foot inset

• insufficient socket adduction

• wide ML dimension of socket

• pain at the pubic ramus

• contracted hip abductors

• poor balance

Lateral Thrust/Shift

Midstance

Characterized by the patient maintaining their shoulders over the base of support while the pelvis moves outside the base of support. Also referred to as Trendelenburg gait.

Potential Causes

• weak hip abductors

• poor alignment

• balance issues

• patient habit

Drop Off

Heel Off (Prosthetic Side)

Characterized by early prosthetic knee flexion near midstance. Appears to buckle or bend.

Potential Causes

• toe lever too short

• knee center too far anterior for the patient’s ability

Excessive Lumbar Lordosis

Throughout gait cycle - mostly during stance

Characterized by patient maintaining an increased lumbar lordosis throughout the gait cycle.

Potential Causes

• insufficient socket flexion

• painful ischial weight bearing (improperly shaped posterior wall)

• weak core muscles or hip extensors

• hip flexion contracture

• short residual limb (decreased functional lever arm)

Medial Whip

Preswing (Toe-off)

Characterized by the heel rising medially at the beginning of swing phase

• knee axis in excessive external rotation

• socket donned with too much external rotation

• silesian belt worn too tightly

• weak limb musculature

Lateral Whip

Preswing (Toe-off)

Characterized by the heel rising laterally at the beginning of swing phase.

Potential Causes

• knee axis in excessive internal rotation

• socket donned with too much internal rotation

• weak limb musculature

Circumduction

Swing Phase

Characterized by swinging the prosthesis laterally in a wide arc during swing phase.

Potential Causes

• excessive resistance to knee flexion

• prosthesis aligned with too much stability

• prosthesis too long

• medial brim pressure

• inadequate suspension

• patient lacks confidence or has inadequate hip flexion

Vaulting

Swing Phase

Characterized by active heel rise during stance of the sound side while the prosthetic side completes swing phase.

Potential Causes

• prosthesis too long

• excessive resistance to knee flexion

• prosthesis aligned with too much stability

• extension bias too strong

• inadequate suspension

• patient habit

Terminal Impact

Terminal Swing

Characterized by rapid forward movement of the shank allowing the knee to reach full extension with too much force prior to heel strike.

Potential Causes

• insufficient knee friction

• extension bias too strong

• patient forcefully extends hip at end of swing phase to ensure the knee is in full extension at initial contact

Uneven Step Length

Terminal Swing (Prosthetic side - long step)

Characterized by fixed relationship between the trunk and the limb. Patient does not have the ability to extend on the prosthetic side

Potential Cause

• insufficient initial socket flexion (unaccommodated hip flexion contracture)

Uneven Step Length

Terminal Swing (short prosthetic step)

Potential Cause

• poor balance

• poor suspension

• weak hip flexors

• painful socket

• insufficient knee friction

• unstable knee

• relatively uncommon

OR initial contact (prosthetic side - short step)

Toe Drag

Initial to Midswing

Characterized by the prosthetic foot contacts the ground near midswing. It stops the progression of swing and is a significant fall risk for the patient.

Potential Causes

• weak hip abductors on the sound side

• poor balance

• poor suspension/socket fit

Poor Suspension

Throughout Swing

Characterized by the prosthesis sliding down the residual limb during swing phase. Creates a functionally long prosthesis. Creates a functionally long prosthesis. Then the limb sinks back into the socket during stance phase and thus creates pistoning.

Potential Causes

• ill fitting socket

• faulty suspension

• patient’s weight fluctuation

Foot Rotation at Heel Strike

Heel Strike to Early Stance

Characterized by the foot rotating laterally upon initiation of stance

Potential Causes

• excessively firm heel or PF bumper

• poor alignment

• weak quad musculature

• patient fear of instability

How to Assess Complex Deviations

• identify the phase of gait that the deviation occurs

• differentiate patient causes from prosthetic causes

• make one change at a time in order to determine the effect

• these deviations often require a combination of incremental changes as well as gait training