Lower Limb Orthoses

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LLO Basics & Biomechanics - Foundation Footings

  • Orthosis: External device; supports/controls body part.
  • LLO (Lower Limb Orthosis): Orthosis for hip, knee, ankle, foot.
  • Goals:
    • Support & Stability
    • Alignment
    • Immobilisation
    • Prevent/Correct Deformity
    • Improve Function
    • Pain Relief
  • Biomechanical Principles:
    • 3-Point Pressure: Two forces countered by a third. 3-point pressure system in lower limb orthosis
    • Ground Reaction Force (GRF): Force from ground on body.
    • Levers: Orthoses modify forces acting as levers.

⭐ The primary goal of an orthosis is to control, guide, limit, or immobilize a joint or body segment.

Foot & Ankle Orthoses - Stepping Stones

  • Foot Orthoses (FOs): Modify foot forces, improve alignment.

    • UCBL: Controls hindfoot valgus/varus. Ind: Flexible pes planovalgus.
    • SMO: Controls foot & ankle. Ind: Severe pronation/supination in children.
    • Heel Cups: Cushioning. Ind: Plantar fasciitis, heel spurs.
  • Ankle-Foot Orthoses (AFOs): Control ankle motion. Bespoke Thermoplastic AFO Classification System

    AFO TypeControl & Key Indications
    Static AFOs
    Solid AFOImmobilizes ankle. Ind: Severe spasticity, post-op, instability.
    GRAFOBlocks DF, aids knee ext. Ind: Crouch gait, quad weakness.
    Dynamic AFOs
    PLS AFOAssists DF, allows PF. Ind: Foot drop (DF weakness).
    Hinged AFOControlled PF/DF (stops). Ind: Spasticity with motor control, knee hyperextension.
    Articulated AFOSpecific joint motion (stops). Ind: Variable; fine-tunes ankle movement.

⭐ Posterior Leaf Spring (PLS) AFO is indicated for isolated dorsiflexion weakness with good mediolateral ankle stability.

Knee & Hip Orthoses - Joint Protectors

  • Knee Orthoses (KOs): Support/protect knee.
    • Prophylactic: Prevent/reduce injury (sports).
    • Rehabilitative: Limit motion post-op/injury (ACL).
    • Functional: Support unstable knee.
    • Unloader/Offloader: Reduce load (osteoarthritis).
  • Knee-Ankle-Foot Orthoses (KAFOs): Control knee, ankle, foot.
    • Types: Conventional (metal/leather), Thermoplastic (lighter).
    • Stance Control KAFOs (SCKAFOs): Lock knee in stance, unlock in swing.
  • Hip Orthoses (HOs) & Hip-Knee-Ankle-Foot Orthoses (HKAFOs):
    • Indications: SCI, polio, muscular dystrophy, post-op hip.
    • HKAFOs control hip, knee, ankle, foot.
    • HKAFO components and adjustments

⭐ A Swedish Knee Cage (KO) is used to control genu recurvatum.

Clinical Rx & Complications - Brace for Impact

  • Common Conditions & Orthotic Choices:

    ConditionTypical Orthotic PrescriptionKey Goals
    Foot dropAnkle-Foot Orthosis (AFO)Dorsiflexion assist, toe clearance
    Genu Varum/ValgumUnloader Knee Orthosis (KO)↓ compartment load, pain relief
    ParaplegiaKAFO / HKAFOStability for standing/ambulation
    Cerebral PalsyVarious AFOs / KAFOsGait aid, spasticity control, support
    Charcot FootCROW BootImmobilize, offload, prevent deformity
  • Materials:

    • Metals (e.g., stainless steel, aluminum alloys): Strong, durable.
    • Plastics (e.g., polypropylene, polyethylene): Light, moldable.
    • Composites (e.g., carbon fiber): High strength/weight, dynamic.
  • Complications: 📌 SKIN (Sores, Kinesthesia altered, Irritation, Nerve palsy).

    • Skin breakdown, pressure sores (⚠️ at bony prominences).
    • Nerve palsy (e.g., common peroneal nerve with AFO).
    • Patient non-compliance due to discomfort/cosmesis.

    ⭐ The most common complication of orthotic use is skin irritation or breakdown.

  • Checkout & Fitting Principles:

    • 3-point pressure check.
    • Trim lines clear prominences, allow intended ROM.
    • Educate: wear schedule, skin checks, hygiene.

Fitting an AFO

High‑Yield Points - ⚡ Biggest Takeaways

  • Foot Orthoses (FO): For pes planus, plantar fasciitis, metatarsalgia.
  • Ankle-Foot Orthoses (AFO): Manage foot drop (peroneal nerve palsy), cerebral palsy spasticity.
  • Knee-Ankle-Foot Orthoses (KAFO): For quadriceps weakness, genu recurvatum, major knee instability.
  • Hip-Knee-Ankle-Foot Orthoses (HKAFO): For paraplegia (SCI), severe global lower limb weakness.
  • Three-point pressure principle: Core biomechanics for orthotic control, deformity correction.
  • Materials: Thermoplastics (polypropylene) favored: lightweight, durable, moldable.
  • Orthotic Checkout: Verifies fit, alignment, function; prevents skin breakdown.

Practice Questions: Lower Limb Orthoses

Test your understanding with these related questions

In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?

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Flashcards: Lower Limb Orthoses

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What is the contraindication to myodesis?_____

TAP TO REVEAL ANSWER

What is the contraindication to myodesis?_____

Ischemic amputation

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