Gait

Lower Limb

Gait

Components of Gait

·        Aim of gait is to keep the body‟s centre of gravity travelling in smooth line ® ¯energy

·        Gait consists of a:

o   Stance phase (60% of the cycle):

§  Heal strike: Forefoot not yet in contact. Knee in full extension. Quads contract to prevent buckling of the knee 

§  Foot Flat: Dorsiflexors slowly relax to bring foot to ground, and hip extensors propel body forward

§  Mid stand: body directly over ankle

§  Heel off: Triceps surae contract

§  Toe off: Hallucis and flexor digitorum longus contract

o   Swing phase (40% of the cycle):

§  Acceleration: iliopsoas contracts (flexes hip), passive knee extension, dorsiflexors contract so foot clears the ground

§  Mid swing 

§  Deceleration: hamstrings stop hyper-extension of the knee and gluteus maximus slows hip flexion

o   Double stance: both feet on ground for 20% of the cycle when walking. When running this % reduces to 0% (ie swing > 50% of cycle so both feet off the ground at some point)

Abnormalities of Gait

·        Causes a limp

·        The main causes of abnormal gait are:

o   Pain ® Antalgic gait (non-specific). Pain ® shortened stance phase on affected leg, shortened swing of opposite leg 

o   Weakness

o   Joint abnormality

·        Usually noticed during stance phase when one leg is bearing the body‟s weight

·        Swing phase:

o   Abnormal heel strike due to:

§  Pain in hind foot (so land on forefoot) 

§  Quad weakness: Knee won‟t extend by itself, so lands flexed and at risk of buckling. Use hand to push thigh posteriorly (foot and hip fixed so backward pressure on distal thigh stops the knee collapsing). May also land on mid foot

o   Foot Slap Gait: during foot flat phase: weakness of dorsiflexors ® foot slaps to the ground rather than controlled lowering

o   Mid-stance:

§  Back-knee Gait: due to:

·        Fixed plantar-flexion deformity of the ankle: Can‟t dorsiflex ankle above neutral so compensate with knee hyper-extension of the knee (slight flexion is normal)

·        Quad weakness: Use hyperextension of the knee to lock the leg straight, rather than quads holding the knee in extension

§  ¯Abductor muscle action: Either weakness (disuse, polio, L5 lesion) or because use puts ­ pressure across the hip joint ® pain if hip pathology:

·        Abductor Lurch or Gluteus Medius Gait: Lateral shift of the trunk over the sore hip in stance, rather than use abductors

·        Trendelenburg Gait: Other hip sags excessively due to inability of abductors to keep pelvis level. Look at hip and shoulder alignment

§  Extensor Lurch or Gluteus Maximus Gait: Don‟t have enough strength in gluteus maximus to hold hip in extension ® risk that the torso collapses forward at the end of stance. Lurch torso backwards to compensate

o  Flat Foot or Calcanial Gait: can‟t toe-off, instead lift whole foot off without extending big toe. Due to:

§  Pain or Rigidity in the fore foot

§  Weakness of plantar-flexors

·        Swing Phase:

o  Paralysis of foot and ankle dorsiflexors can cause one or more of the following during toe clearance:

§  Steppage or Drop Foot Gait: flex knee more in swing phase so the foot clears the floor

§  Hip-hike Gait: Lift pelvis to help the foot clear the ground.  Can also be due to a stiff knee 

§  Circumduction Gait: Swing leg out to the side so the foot clears the ground. Can also be due to a stiff knee

o   Abnormal pelvic rotation: Weakness of hip flexors on the swing side ® ¯ acceleration. Compensate with ­forward pelvic rotation to „flick‟ the swing leg forward

o  Hip Fusion: fused hip on the stance side ® ¯ pelvic rotation on the swing side ® decreased swing length

·        Abnormal gaits by causative muscles:

o  Quads: Abnormal heel strike, back-knee gait

o  Abductors: Abductor lurch/Gluteus medius or Trendelenburg gait

o  Gluteus Maximus: Extensor lurch

o  Plantar flexors: Flat foot/calcanial gait

o  Dorsiflexors: foot slap, steppage/drop foot, hip-hike or circumduction gait

o  Iliopsoas: abnormal pelvic rotation

·        Other:

o  Broad based gait: impaired balance/co-ordination/vision, drunk

o  Short leg: have to drop ipsilateral hip in stance phase so the foot can reach the floor

Observing Gait

·        Walk the patient

·        Other aspects of gait to observe:

o  When observing gait, focus on the pelvis first:

§  Pelvic tilt

§  Pelvic rotation

o  Lateral shift of the torso

o  Width of base: normally 6 – 8 cm 

o  Stride length (distance from where the heel strikes on one side to where the heel strikes again on that same side) 

o  Step length (distance from where the heel strikes on one side to where the heel strikes on the opposite side. Normally the same for both sides)

o  Also observe shoulder movement

·        Once you‟ve identified the gait, think of causes from top down:

o  Stroke

o  Spinal chord lesion

o  Nerve root

o  Peripheral nerve

o  Muscle (either weakness or pathology)

o  Joint

o  Bone (eg fracture)