Knee Gait Deviations

Chapter 12

Knee Gait Deviations

• Sagittal (most common)

• Frontal

• Transverse (often inconsistent and unreliable)

Sagittal Deviations

• Limited knee flexion

• Knee hyperextension

• Extensor thrust

• Excess knee flexion

• Excess contralateral knee flexion

• Wobble

Limited Knee Flexion

• Definition

  • Less than normal flexion for given phase

• Phases

  • LR, PSw, ISw

• Functional significance

  • LR: decrease shock absorption and quads demand

  • PSw, ISw: disrupts foot clearance and may lead to foot drag

• Causes

  • Quads weakness (LR)

  • Quads or PF spasticity (LR, PSw, ISw)

  • Knee or patella-femoral knee joint pain

  • Knee extension contracture

  • Limited thigh advancement due to over-active hamstrings or weakness of hip flexors

  • Impaired proprioception

  • Primitive muscle synergies interfering with ability to combine knee flexion with extension at adjacent joints

Limited Knee Flexion - Causes LR

• Quads weakness

• Quads spasticity

Limited Knee Flexion - Quads Weakness

• This is a VOLUNTARY limitation of knee flexion

• Hip extension (glutes, adductor magnus) active to retract thigh

• Premature ankle PF (soleus) to limit tibial advancement

Limited Knee Flexion - Quads Spasticity

• This is an INVOLUNTARY limitation of knee flexion

• Knee extension (Rectus Femoris, Vastii) extend knee

• Quick stretch of Quads during stance phase knee flexion engages spastic response

Limited Knee Flexion - Other Causes

• Hip flexor weakness (PSw to ISw)

  • Passive double-pendulum knee flexion starts with active hip flexion

  • The thigh stays vertical and the knee relatively extended

• Inappropriate hamstring activity

  • Prolonged or premature hamstrings during PSw

Knee Hyperextension

• Definition

  • Knee posterior to anatomic neutral (genu recurvatum)

• Phases

  • IC, LR, MSt, TSt, PSw

• Functional significance

  • Decreased quads demand

  • Decreased WA shock absorption and forward progression

  • Decreased MSt, TSt, PSw forward progression and prep for SLA

• Causes

  • Quads weakness (LR)

  • Quads weakness + PF weakness (SLS)

  • Quads and PF spasticity

  • PF contracture (severe)

One Knee Hyperextension Mechanism

• Constraint of tibia during proximal forward momentum

Extensor Thrust

• Definition

  • Forceful motion of knee toward extension (dynamic, rapid)

• Phases

  • LR, MSt

• Functional significance

  • Decreased quads demand

  • Decreased WA shock absorption and forward progression

• Causes

  • Quads weakness

  • Quads or PF spasticity

  • Forefoot contact + PF contracture - “jump knee”

  • Proprioceptive deficits at knee

Excess Knee Flexion

• Definition

  • Greater than normal knee flexion for given phase (”Crouch gait”)

• Phases

  • LR, MSt, TSt, TSw

• Functional significance

  • WA, SLS: increased quads demand

  • TSw: decreased step length and forward progression

• Causes

  • PF weakness/excessive length

  • KF/HF contracture/spasticity

  • Primitive pattern

  • Knee pain

Excess Knee Flexion - LR

• Excessive ankle DF

Excess Knee Flexion - MSt

• Excessive ankle DF

Excess Knee Flexion - TSt

• Excessive ankle DF

• No heel rise

• Lack of trailing limb posture

Excess Contralateral Knee Flexion

• Definition

  • Greater than normal knee flexion of contralateral limb

• Phases

  • Contralateral limb’s stance phases

• Functional significance

  • Lowers body toward ground

  • Functionally lengthens reference limb

• Causes

  • Same as previous

  • Intentional KF to lower short limb to the ground

Wobble

• Definition

  • Rapid alternating flexion and extension during a single phase

• Phases

  • LR, MSt, TSt

• Functional significance

  • Decreased forward progression and stability

  • Increased energy cost

• Causes

  • Lack of proprioception (search for stability)

  • PF or quads hypertonicity (clonus)

Frontal Deviations

• Abduction (valgus)

• Adduction (varus)

Excessive Valgus

• Definition

  • Excess lateral deviation of distal tibia from knee’s center “knock knee”

• Phase

  • Stance phase

• Functional significance

  • Decreased stability

  • May necessitate compensation at other joints

  • Pain

• Causes

  • Joint instability

  • Bony deformity

  • Pain

  • Ipsilateral abductor weakness

  • Ipsilateral trunk lean

Excessive Varus

• Definition

  • Excess medial deviation of distal tibia from knee’s center

• Phases

  • Stance phase

• Functional significance

  • Decreased stability

  • May necessitate compensation at other joints

  • Pain

• Causes

  • Joint instability

  • Bony deformity

  • Degenerative joint changes

  • Pain

Static Causes

• Static malalignment mechanisms

  • Congenital or developmental deformities

  • Trauma (MCL/LCL strain) → ligamentous laxity → valgus/varus deformity

Dynamic Causes

• Dynamic factors

  • Persistent yielding to malaligned tibia

    • Longterm OA, RA, paralytic gluteus medius

Static vs. Dynamic Causes

• Bone growth responds to the forces it experiences