Orthotic and Podiatric Biomechanics 2 Flashcards
Pressure Insoles
- A pressure sole is placed inside shoe to dynamically measure forces applied to
small areas of the foot - Measurements are taken throughout the stance phase of the gait cycle, creating a
moving image or series of frames to visualize the force distribution. - The pressure sole provides quantitative data on force patterns, allowing a detailed
view of force movement from heel to toe along the lateral side of the foot, which
was previously inferred from shoe wear patterns.
Pressure
Force per square area
3 common foot orthoses
- Rearfoot varus wedge
- Forefoot medial wedge
- Heel lifts for Achilles tendon
Rear Varus Wedge
- Used for patients with excess pronation or flat feet to improve subtalar joint control
- Placed under the entire heel with a thicker side on the medial side
- Common wedge angle is about four degrees, but this can vary based on the patient’s assessment
Treatment for forefoot Inversion (forefoot varus)
- Medial wedge placed under the first metatarsal phalangeal joint
Heel lifts for achilles Tendon
Heel lifts are used to reduce stress on the Achilles tendon,
particularly for patients with tendinitis or Sever’s Disease
Sever’s Disease
Inflammation of the heels growth plate in children, often due to repetitive stress or overuse
Ankle-Foot Orthosis
External device used to control motion, stabilize gait, reduce pain, correct flexible deformities, and prevent fixed deformity progression
Common uses for AFOs
Primarily for patients with drop foot due to stroke, MS, Spina Bifida, spinal cord injury, Post-Polio syndrome, birth defects, and severe ankle instability
Design features of AFOs
Provides rigidity with some flexibility; may include an articulated hinge or made from more flexible material if needed for additional movement.
Knee braces
Provide external support to reduce reliance on ligaments and improve stability
Prophylactic knee braces
Help protect injured knees from valgus stresses, especially in high-risk sports like football and skiing
- 20-30% greater resistance to MCL injury from a lateral blow
Effectiveness of Prophylactic knee braces
- Research suggests a reduced risk of injury, but findings are inconclusive.
- Knee braces may reduce straight sprint speed and cause early fatigue by restricting muscle perfusion, potentially decreasing
stability
Considerations Knee brace prophylactic
Brace migration, added weight, potential loss of proprioception, and performance impact.
Functional Knee Braces
Gained popularity after Joe Namath’s (NFL quarterback) successful comeback post-knee injury; designed to reduce knee instability following ACL injury and prevent additional injuries during athletic activities
Functional Knee braces: purpose and usage
Initially marketed for athletes with knee instability in sports requiring rapid direction changes; recommended after ACL reconstructive surgery to reduce strain
on the graft.
Functional Knee braces: Benefits
Some users report subjective improvements in knee stability, pain reduction, performance, and confidence, despite few controlled studies on efficacy
Functional Knee braces: Limitations
Laboratory tests show tibial rotation and translation limitations, but these effects diminish under stress loads. Functional knee braces may also increase energy expenditure and muscle fatigue
Proprioception & Confidence
- Braces provide limited proprioceptive benefits and may increase injury risk by offering a false sense of confidence.
- Functional knee braces are not harmful but should be used alongside proper rehabilitation, activity modification, and strengthening, flexibility, and technique improvements, which are more important for treating ligamentous knee injuries
Unloader Knee Braces
- Can help relieve osteoarthritis pain in early and mid stages of disease
- May reduce KAM by limiting varus thrust, slightly increasing joint space in the medial tibiofemoral compartment
Knee OA
commonly affects medial compartment, causing joint space narrowing and often linked to varus knee thrust during early stance phase
Knee Adduction Moment
a rotational force that increases medial knee loading, contributing to OA progression
