Q4: Knee Orthoses Flashcards
Primary Uses
KOs
- Coronal Issues
- Arthritis
- Hyperextension
Suspension is a primary issue
Tibial Plateau
Functional Anatomy of the Knee
Lateral aspect is smaller and convex
Medial aspect is larger and concave
Menisci
Functional Anatomy of the Knee
Create an increase in congruence between tibia and femur
Menisci
Relevant Characteristics
- Viscoelastic - shock attenuation
- Made of fibrocartilage
- Richly innervated
- Center is avascular
Femoral Condyles
Functional Anatomy of the Knee
Asymmetrical
* Lateral - wider but shorter
* Medial - thinner but longer
Lateral/Medial divided by femoral trochlea
ACL/PCL
Functional Anatomy of the Knee
rise from the intercondylar notch
Facets of the Femur
Functional Anatomy of the Knee
- Lateral - Concave and largest
- Medial - Convex
- Odd - only articulates at the end range of knee flexion
Patellofemoral Joint Syndrome
Functional Anatomy of the Knee
- pain is common in the athletic population
- females more likely to develop
- Managed conservatively (unless no improvement after 6 months - then Sx)
ACL
Primary Roles of Ligaments
Resist anterior displacement of tibia relative to femur
Secondary - resist varus when extended
PCL
Primary Roles of Ligaments
Resist posterior displacement of the tibia relative to the femur
Secondary - Resists varus when extended
LCL
Primary Roles of Ligaments
Resists varus when knee is 30 degrees flexed
Secondary - resists ext. rotation below 50 degrees of flexion
MCL
Primary Roles of Ligaments
Resists valgus angulation
Secondary - Limits rotation with help of ACL
MCL vs. LCL
Biomechanics of the Knee
- MCL has more stretch than the LCL
- MCL attaches to med/meniscus (LCL does not)
Stability of the Knee
Biomechanics of the Knee
13 muscles assist to knee stabilization
Meniscis also assist by increasing SA; minimal perfusion
Axis of Rotation
Knee Joint
Polycentric in nature
* Follows a J-shaped path
* Tibia rolls and glides on femur
* Flexion initiated by int. rotation of tibia
Screw Home Mechanism
Locking - medial tibial condyle moves anterior (ER)
Unlocking - medial tibial condyle moves posteriorly (IR)
Patellofemoral Syndrome
Conservative Management
- PT - strengthening
- Ox - FOs; 1 study shows Bauerfiend Genutrain (KO sleeve) helps
- Taping - not as much evidence
Prophylactic KOs
Ox Design
Prevent Injury
* inhibit coronal motion
* can have one or two sidebars (single axis)
Post-Op KOs
Ox Design
Treat acute injury
* prevent excessive loads on impaired ligament
* allow early return to activity
* longer lever arms
Functional KOs
Ox Design
Return to ADLs/Athletics
* bilateral sidebars
* polycentric joints
* inhibit ant. migration of tibia on femur (protect ACL)
Limitations of KOs
Ox Design
- Migration distally - suspension issues
- Shorter lever arms than KAFOs
- Only crosses the knee (no transverse motion control)
Injuries to other athletes can occur too
“Unhappy Triad”
Knee Injuries
ACL, MCL, and medial Meniscus
Sx is almost always indicated
AKA: O’Donoghue’s Triad
ACL
Knee Injuries
Noncontact (70%)
Contact (30%)
50/50 if Sx is needed
ACL comprised of
fibrocartilage; inability to heal
PCL
Knee Injuries
MOI - forced HE from direct blow
50% of time correlated with other ligament injuries
MCL
Knee Injuries
MOI - Valgus stress on flexed knee
Commonly injured with other ligaments (ACL usually)
Most common ligament injury in knee
LCL
Knee Injuries
MOI - direct blow resulting in excessive varus
Isolated cases are very rare
MCL Injury Treatment
Grade I/II Sprains
Compressive knee sleeve OR adjustable ROM KO
PCL Injury Treatment
Grade I/II Sprains
Weight bearing as tolerated; KO set in terminal extension
LCL Injury Treatment
Grade I/II Sprains
KO locked in terminal extension
ACL Injury Treatment
Grade I/II Sprains
Adjustable ROM KO
ACL Injury Treatment
Grade III Sprains
Reconstruction for more active individuals
Less active peoples can return to preinjury levels with PT and Ox
Adjunct Therapies
Grade I/II Sprains
- PT - return to activies when 80% strength and ROM returns
- NSAIDs
PCL Injury Treatment
Grade III Sprains
Conservative Management; Sx only if CM does not work
Fibroblast allow for potential healing; Ox for 2-4 weeks
MCL Injury Treatment
Grade III Sprains
Conservative Management for isolated injuries
KO set in 30 degrees of flexion with PT
MCL Injury Treatment
Grade III Sprains
Conservative Management for isolated injuries
KO set in 30 degrees of flexion with PT
LCL Injury Treatment
Grade III Sprains
Reconstruction typically indicated
Efficacy of KOs
- Prophylactic - favorable outcome but increased fatigue
- Rehabilitative - Ox are a primary reason for reduced Sx management
- Functional - without a brace, Sx outcomes not favorable
“Does bracing patients that underwent ligament
reconstruction decrease the likelihood of future re-
injury?”
Some of the strong studies say “NO”
Medial Compartment OA
Most common location in knee
Occurs with varus when medial compartment bears more than 70% of axial load
Lateral Compartment OA
Occurs with valgus when lateral compartment bears close to 50% of axial load
More common for individuals with RA
Knee Adduction Moment
GRF passes medial to the knee center creating sudden adduction; OA of medial compartment often seen
OA - Coronal Plane Alignment
KO Design
LoadShifter Mechanism
* The patented LoadShifter technology allows tool-less
adjustability via the innovative SnapLock allowing the
practitioner to easily accommodate the patient’s
anatomy or the degree of unloading quickly and easily.
