Lower Limb Orthoses

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.
  • 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.

  AFO Type	Control & Key Indications
  Static AFOs
  Solid AFO	Immobilizes ankle. Ind: Severe spasticity, post-op, instability.
  GRAFO	Blocks DF, aids knee ext. Ind: Crouch gait, quad weakness.
  Dynamic AFOs
  PLS AFO	Assists DF, allows PF. Ind: Foot drop (DF weakness).
  Hinged AFO	Controlled PF/DF (stops). Ind: Spasticity with motor control, knee hyperextension.
  Articulated AFO	Specific 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.
  • 

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

Clinical Rx & Complications - Brace for Impact

• Common Conditions & Orthotic Choices:

  Condition	Typical Orthotic Prescription	Key Goals
  Foot drop	Ankle-Foot Orthosis (AFO)	Dorsiflexion assist, toe clearance
  Genu Varum/Valgum	Unloader Knee Orthosis (KO)	↓ compartment load, pain relief
  Paraplegia	KAFO / HKAFO	Stability for standing/ambulation
  Cerebral Palsy	Various AFOs / KAFOs	Gait aid, spasticity control, support
  Charcot Foot	CROW Boot	Immobilize, 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.

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.