POT206P Comprehensive Final Scope Study Notes: Orthotics and Gait Analysis

Orthotics Fundamentals and Definitions

• Definition of an Orthosis: An externally applied device used to compensate for impairments of the structure and function of the neuromuscular and skeletal systems.   - Simple Interpretations:     - Supports weak or damaged joints.     - Improves alignment.     - Controls abnormal movement.     - Assists function.     - Protects painful or unstable areas.     - Improves participation in daily activities.
• International Organisation for Standardisation (ISO): Established to provide clear naming of orthotic devices, facilitate communication between health professionals, ensure consistent documentation, and standardize the classification of orthoses and components.
• Naming Conventions for Orthoses:   - Anatomical Naming: Based on the body parts or joints the orthosis crosses. Orthoses are named from distal to proximal. Examples: FO (Foot Orthosis), AFO (Ankle-Foot Orthosis), KO (Knee Orthosis), KAFO (Knee-Ankle-Foot Orthosis), WHO (Wrist-Hand Orthosis), TLSO (Thoracolumbosacral Orthosis).   - Functional Naming: Based on what the device does. Example: GRAFO (Ground Reaction Ankle-Foot Orthosis).   - Nominal Naming: Named after the designer, origin, or laboratory. Examples: Arizona AFO, UCBL (University of California Biomechanics Laboratory) orthosis.
• Orthotic Components and Categories:   - Structural Components: Provide support and biomechanical function (e.g., struts, frames, bands).   - Articulating Components: Allow controlled movement (e.g., hinges, joints).   - Interface Components: Contact the skin and improve comfort (e.g., padding, liners, straps).   - Cosmetic Components: Improve appearance and patient acceptance (e.g., covers, cosmetic finishes).
• Static vs. Dynamic Orthoses:   - Static Orthosis: Does not allow motion across the involved joint. Primary purposes include stabilization, immobilization, protection, and support.   - Dynamic Orthosis: Allows, assists, resists, or controls movement. Primary purposes include permitting motion within specific limits, assisting motion, resisting unwanted movement, or guiding movement.
• Goals of Orthotic Treatment:   1. Stabilize weak or paralysed segments or joints.   2. Support damaged or diseased segments or joints.   3. Limit or augment motion across joints.   4. Control abnormal or spastic movements.   5. Unload distal segments.

Clinical Reasoning and Decision-Making

• Orthotic Principles: Successful orthotic intervention depends on patient assessment, biomechanics, functional needs, patient goals, skin safety, alignment, comfort, compliance, appropriate material choice, and proper follow-up. The central guiding idea is that the device must solve the patient’s problem without creating new problems.
• Clinical Reasoning: A complex cognitive process leading to meaningful interpretation of patient problems and the formulation of an effective management plan. It bridges "What you know" (anatomy, pathology, biomechanics, orthotic principles) with "What you find" (patient history, signs, symptoms, physical assessment, imaging, gait findings).
• Clinical Decision-Making Process (Sequential Steps):   1. Patient assessment.   2. Problem identification.   3. Referral and collaboration, if needed.   4. Goal setting.   5. Orthotic options.   6. Orthotic selection.   7. Implementation.   8. Patient education.   9. Follow-up and evaluation.   10. Documentation.
• Diagnosis vs. Prognosis:   - Diagnosis: Identifies what condition the patient has; based on signs, symptoms, history, and tests; present-focused. Example: Grade II ankle sprain.   - Prognosis: Predicts the likely course and outcome; based on diagnosis, age, health, and treatment response; future-focused. Example: Expected recovery in $6-8$ weeks with rehabilitation.
• Problem Categories:   - Primary Problem: The direct result of the diagnosis (e.g., Ankle plantarflexion contracture after stroke).   - Secondary Problem: Compensation or associated problem caused by the primary problem (e.g., Knee hyperextension thrust caused by plantarflexion contracture).   - Clinical Rule: Do not only treat what you see; find the root cause.

Assessment and Physical Parameters

• Comprehensive Orthotic Assessment Components:   - History: Diagnosis, symptoms, onset, functional limitations, patient goals.   - Physical Assessment: Posture, ROM, strength, sensation, tone, skin, alignment.   - Gait Analysis: Observation of gait phases and deviations.   - Diagnostic Imaging: Bony alignment, fractures, deformity, degeneration.   - Skin Integrity: Pressure areas, scars, redness, fragile skin.   - Biomechanical Assessment: How joint or foot position affects function.   - Functional Assessment: ADLs (Activities of Daily Living), work, school, walking, stairs, participation.
• Range of Motion (ROM) Definitions:   - Active ROM: The patient moves the joint independently.   - Passive ROM: The clinician moves the joint for the patient.   - Clinical Utility: Helps decide orthotic trimlines, joint positioning, and whether a deformity is flexible (correctable) or rigid.
• Standardized ROM Test Procedure:   1. State the joint being tested.   2. Position the patient.   3. Stabilize the correct body segment.   4. Move the joint through the available range.   5. Measure with a goniometer or inclinometer.   6. Record the degrees.   7. Compare to the normal range.   8. Note pain, stiffness, end-feel, or limitation.
• Case Example: Ankle Dorsiflexion ROM Test:   - Patient stands in weight-bearing lunge position with foot flat on floor.   - Patient bends knee forward toward the wall while the heel stays down.   - Measurement taken via goniometer or digital inclinometer.   - Observations include limited dorsiflexion, early heel rise, and forefoot pressure.
• Normal ROM Reference Values:   - Ankle dorsiflexion: $5-10\,^{\circ}$   - Ankle plantarflexion: $50\,^{\circ}$   - Supination: $45-60\,^{\circ}$   - Pronation: $15-30\,^{\circ}$   - Inversion: $35\,^{\circ}$   - Eversion: $15\,^{\circ}$   - Forefoot adduction: $20\,^{\circ}$   - Forefoot abduction: $10\,^{\circ}$   - Hallux MTP extension: $70\,^{\circ}$   - Hallux MTP flexion: $45\,^{\circ}$   - MTP extension/flexion (others): $40\,^{\circ}$
• Manual Muscle Testing (MMT) - Ankle Dorsiflexors:   - Patient lifts foot toward shin against clinician resistance.   - Weakness Indicators: Poor toe clearance, foot drop, toe drag, foot slap, poor heel contact.   - Clinical Decision: Weak dorsiflexors usually require an AFO rather than just an FO because the issue involves ankle control.
• Skin Integrity and Conditions:   - Callus: Repeated pressure/friction; larger than corns; found on weight-bearing areas (soles, heels, metatarsal heads). Relevance: Shows overloading; FO should offload and redistribute load.   - Corn: Smaller than callus; hard centre; inflamed surrounding skin; painful when pressed. Found on tops/sides of toes. Relevance: Needs pressure reduction/accommodation.   - General Risks: Redness, scars, fragile skin, wounds, sensation loss, and ulcers increase risk of non-compliance and device rejection.
• Diagnostic Imaging Indicators:   - X-ray: Bony alignment, fractures, deformity, degenerative changes, standing alignment.   - MRI: Soft tissue involvement, ligaments, tendons, neural structures.   - CT scan: Complex bony anatomy, torsion, detailed bone structure.

Clinical Goals and Education

• SMART Goals:   - S: Specific.   - M: Measurable.   - A: Achievable.   - R: Relevant.   - T: Time-bound.   - Example: Patient will increase walking tolerance from $5\,\text{minutes}$ to $15\,\text{minutes}$ within $6\,\text{weeks}$ using prescribed AFO.
• Goal Categories:   - Protection: Prevent skin breakdown.   - Prevention: Prevent deformity progression.   - Correction: Correct flexible foot alignment.   - Functional Improvement: Improve walking safety.   - Participation: Allow return to school, work, or community activity.
• Patient Education and Warning Signs:   - Education must cover donning/doffing, wearing schedule, break-in period, skin checks, and cleaning.   - Warning Signs to Report: Redness that does not disappear, pain, numbness/tingling, skin breakdown, blisters, increased swelling, device discomfort.
• The Interdisciplinary Team:   - Patient: Provides goals and follows plan.   - Physician: Diagnoses and prescribes.   - Orthotist: Assesses, designs, fabricates, fits.   - Physiotherapist: Gait/mobility training.   - Occupational Therapist: ADLs and functional independence.   - Nurse: Skin/wound care.   - Social Worker: Funding and support systems.   - Family/Caregiver: Daily support.

Fabrication and Design of Foot Orthoses

• The Fabrication Process:   1. Assessment and measurements.   2. Impression, cast, or digital scan.   3. Negative mould creation.   4. Positive mould creation.   5. Positive mould modification.   6. Material selection.   7. Device fabrication (thermoforming/laminated).   8. Trimming and finishing.   9. Fitting and alignment check.   10. Patient education.   11. Follow-up and adjustments.
• Foot Orthosis (FO) Definition: A device that confines to the foot only and does not encompass the ankle. Works mostly during weight-bearing and is usually placed inside a closed shoe (making the shoe part of the orthotic system).
• Components of a Foot Orthosis:   - Medial Longitudinal Arch Support: Located on the medial side; supports the medial arch and controls pronation.   - Metatarsal Pad: Located under the forefoot, proximal to the metatarsal heads; reduces pressure and supports the transverse arch.   - Lateral Longitudinal Arch Support: Located on the lateral side; supports lateral arch and assists varus control.   - Heel Bed: Located under the heel; holds the calcaneus and provides hindfoot control.   - Wedges and Posts: Added to resist or accommodate varus or valgus tendencies.   - Toe Bed: Supports or accommodates toes based on design.
• Three-Quarter FO vs. Full-Length FO:   - Full-Length: Covers whole foot; provides more total support and better positioning; requires more toe box space.   - Three-Quarter: Ends at metatarsals/sulcus; less forefoot control; higher shoe compatibility; less stability (may migrate).
• Cavus Foot (High Arch):   - Characteristics: High medial arch, rigid stance, reduced shock absorption, pressure on heel/ball/5th metatarsal.   - Treatment: Soft accommodative FO, cushioning under heel and forefoot, lateral arch support, metatarsal pad.
• Common Foot Deformities and Treatments:   - Pes Planus: Flat/pronated foot, calcaneus everted. Treatment: Medial arch support, medial posting.   - Rearfoot Varus: Heel inverted. Treatment: Lateral heel wedge or lateral rearfoot post.   - Forefoot Varus: Forefoot inverted relative to rearfoot. Treatment: Medial forefoot post.   - Forefoot Valgus: Forefoot everted relative to rearfoot. Treatment: Lateral forefoot post.   - Equinus Deformity: Limited dorsiflexion. Treatment: Heel raise, rocker sole.   - Plantarflexed First Ray: First metatarsal sits lower. Treatment: First ray accommodation, pressure relief.

Foot Biomechanics and Gait

• The Arches of the Foot:   - Medial Longitudinal: Primary weight-bearing and shock absorption.   - Lateral Longitudinal: Shallow support and lateral stability.   - Transverse Arch: Provides stiffness and rigidity.
• Kinetic Chains:   - Open Kinetic Chain: Foot moves freely (e.g., Swing phase).   - Closed Kinetic Chain: Foot is fixed on the ground (e.g., Stance phase).
• Foot Function in the Gait Cycle:   - Heel Strike/Initial Contact: Calcaneus contacts; subtalar joint pronates for shock absorption.   - Midstance: Weight distributed across arch; subtalar joint neutral.   - Terminal Stance/Push-off: Supination stiffens foot; windlass mechanism activated; propulsion via hallux.   - Swing Phase: Foot clears ground via dorsiflexion.
• Normal Gait Parameters:   - Definition: Rhythmical alternating movements of trunk and limbs resulting in forward progression of center of gravity.   - Prerequisites: Equilibrium (upright posture), Locomotion (rhythmic stepping), Musculoskeletal integrity, Neurological control.   - Functions: Forward progression, Stability, Shock absorption, Energy conservation.   - Values:     - Cadence: $90-120\,\text{steps/min}$.     - Velocity: Approx. $1.34\,\text{m/s}$.     - Gait Cycle Breakout: Stance ($60\%$), Swing ($40\%$).
• The Eight Phases of Gait:   1. Initial Contact ($0\%$): Heel contacts floor.   2. Loading Response ($0-10\%$): Weight acceptance/shock absorption.   3. Midstance ($10-30\%$): Body moves over supporting foot.   4. Terminal Stance ($30-50\%$): Heel rises, body progresses forward.   5. Pre-swing ($50-60\%$): Limb unloads for swing.   6. Initial Swing ($60-73\%$): Foot leaves ground.   7. Mid-swing ($73-87\%$): Limb advances for clearance.   8. Terminal Swing ($87-100\%$): Limb prepares for next heel strike.
• Pathological Gait Types:   - Trendelenburg Gait: Contralateral pelvic drop during single limb stance; caused by gluteus medius weakness.   - Antalgic Gait: Pain-avoidance; reduced stance time on painful limb, rapid weight transfer.   - Vaulting: Excessive plantarflexion of stance foot to clear opposite swing limb; caused by limb length discrepancy or lack of knee flexion.   - Circumduction: Lateral arc of foot during swing; caused by long swing limb or hip weakness.   - Steppage/Foot Drop: Exaggerated hip/knee flexion to prevent toe drag; caused by weak dorsiflexors.   - Scissor Gait: Spastic gait where legs cross; excessive hip adduction; common in Spastic Cerebral Palsy.   - Crouch Gait: Excessive ankle dorsiflexion and hip/knee flexion in stance; high quadriceps demand.   - Ataxic Gait: Coordination failure; wide base, irregular stepping; caused by cerebellar dysfunction or nerve damage.