Knee Joint Flashcards
What are the 2 joints of the knee?
tibiofemoral joint
•patellofemoral joint
Patellofemoral articulation have what type of biomechanics?
7x body weight w/squats
2-3x body weight descending stairs
Reaction force
Motion of the knee is a _____ articulation allowing patella to move __ cm causally in full flexion.
Sliding
7
Note: max contact b/t femur/patella 45 degree of flexion
An increased Q angle can result in
Patella instability characterized by patella subluxation/dislocation
Name the 3 characteristics that lead to an increased Q angle.
Femoral anteversion
Genu Valgum
External tibial torsion/pronated foot
What are the biomechanics of the tibiofemoral articulation?
What is its motion?
Joint reaction force
3x body weight walking
4x body wight climbing
3 degrees of hyper extension to 155 degrees of Flexion in Sagittal plane. Thigh-calf limiting factor to full flexion
Norm gait ROM 0-70 degree
What is the relevance of of Tibiofemoral articulation rotates instant center, points at direct contact?
Rolls posterior
Knee flex: instant center of rotation on femur moves posteriorly
Allows: inc knee flexion by avoids impingement
Which side is the longest on Tibial plateau and what is the cause of screw home mechanism?
Medial
Tibial Externally rotates 5 degrees in 15 degrees of extension
What is is the relevance of rotation in TF articulation?
Locks knee decreasing the work performed by quads while standing
The tibia is subject to ——— w/knee flexion. External rotates on femur as the knee performs what action?
Internal rotation
Extends
The lateral condyle shifts in what direction on the axis of rotation when the knee is in flexion?
Posterior
Tibial internal rotation occurs with what movement?
Knee flexion
Note: 120 degrees to full flexion both condyle participate in Roll Back
Which ligament has a varus stress at the knee?
Lateral collateral ligament
Which collateral ligament experiences a valgus stress?
Superficial portion of the medial collateral ligament
What is the function of the stability of the knee?
Primary: static restraint to anterior translation
Also, play a role in axial rotation
What are the stabilizing components for the anterior cruciate liagment of the knee?
Anteromedial bundle tight in Flexion
Posterolateral bundle tight in Extension
What is the primary function of the posterior cruciate ligament?
Primary static restraint to posterior translation
What is the primary stabilizer of external tibial rotation of the knee?
Posterolateral corner
Knee and joint pain must b distinguished b/t what?
Radiating or referred pain and local knee problems
The knee joint can receive Refetred pain from where else in the body?
Low back Hip Ankle Foot Note: frequently the knee joint is injured b/c of position exposure to outside trauma
What is the most commonly injuries joint of the body?
Knee joint
Note: the knee relies mainly on ligaments and muscles for its stability
True or Fail: Joint effusion (swelling) provides stability to the knee.
True
Note: all ortho exams will be painful
True or False:
Reactive muscle spasms and swelling will make testing unreliable to an acute knee injury.
True
Are soft tissue injuries usually the result of overuse, disuse or both?
both
Knee pain d/t pronation, supination, lower leg torsion, patellar tracking problems and an increased Q-angle are the result of overuse or disuse?
Disuse
Notes: disuse is the biomechanics predisposition of knee joint and pain
The history concerning activities d/t overuse are what?
W/repetitive movements or prolonged awkward positing of the knee
Patellofemoeral arthralgia, patellar instability and tracking disorders are all common presentations for what group of people? ID the specific are of knee pain.
Athlete w/anterior knee pain
Elderly pt’s commonly presents w/knee pain and stiffness as a result of what condition?
OA
Osgood-Schlatter dz is a condition that ___ experience pain around or directly on the tibial tuberosity.
Young athlete
Chronic ACL damage is a common presentation for pt’s with what condition?
Instability
A pt presents with painful locking of the knee. This likely is a common presentation for what condition?
Meniscus tear
An ACL tear or patellar dislocation present in the history indicates a trauma with what motion?
Hyperextension
The pt has a history of a tear in the PCL. What motion has most likely occurred from this type of trauma?
Hyper-flexion
A history of a sudden declaration trauma is likely to be due to what type of damage and specifically to what muscle filter?
ACL tear
Valgus force with no rotation is a tear to what specific ligament?
MCL
Valgus force w/ration (foot fixed) can lead to trauma on what fibers?
ACL, MCL and menisci
Which of the following is not d/t valgus force w/rotation to the knee? ACL, MCL, PCL and menisci
PCL
What structure make up the terrible triad of the knee?
What is the aka of this condition?
ACL
MCL
Meniscus
O’Donoghue triad
O’Donoghue triad aka is
The Terrible Triad
Note:ACL, MCL, meniscus
What injury occurs when the foot is planted or fixed and outside force applied in a valgus direction?
The terrible triad aka O’Donoghue triad
Made of Anterior Cruciate Ligament, Medial Collateral ligament and Meniscus
Which of the following are included in the “Terrible Triad”? Anterior Cruciate Ligament Posterior Cruciate Ligament Medial Collateral ligament Lateral Collateral ligament Meniscus
Anterior Cruciate Ligament, Medial Collateral ligament and Meniscus
A pt has a history of feeling a pop and pain deep with immediate swelling (hemarthrosis) to the knee. What fiber has been damaged?
Anterior cruciate ligament
A pt has generalized knee pain, instability that prevents to return to sports and difficulty weight bearing. These are symptoms involve what ligament?
Anterior cruciate ligament (ACL)
On physical exam the doc might observe an effusion and what else during inspection?
Quadricep avoidance gait (pt will not actively extend the knee).
The lack of what motion is secondary to meniscus injury or arthrofibrosis?
Full extension
The McMurray varus/valgus stress test evaluates the motion of what structures?
Meniscus or concomitant ligamentous injuries
ACL tears are common athletic injuries leading to what type of instability of the knee?
Anterior and lateral rotatory instability
The dx of an ACL tear or damage can be supspected clinically with the presence of a dame to the knee. What test is required to confirm dx? What ortho is used to check for damage?
Traumatic knee effusion w/increased laxity on Lachman’s test (also any drawers test). This requires a MRI to confirm dx.
The treatment of choice for ligamentous reconstruction depends upon what?
Pt’s age and activity level
Will a chronic ACL issue have a previous acute presentation in the history?
Yes
A pt complains of instability of the knee and not pain with the occurrence of a non-traumatic joint line swelling and an acute presentation in their history. This pt likely has an issue with what ligament?
ACL
ACL tears occur from hyperextension and what other actions?
Sudden stopping/cutting
Quadriceps contraction
ACL tears occur from hyperextension a sudden stop and quadriceps contraction. Contact with rotation can affect what structures?
Menisci and MCL
What section of the ACL usually tears?
Mid-substance
What other structure may rupture with the anterior cruciate ligament?
Middle Genicular artery
True or False
An anterior cruciate ligament causes sudden selling and is Stengel and painful.
True
A. What visual information can be gathered from taking a MRI of the ACL?
B. Why are x-ray’s taken?
A. Integrity of the ACL
B. To rule out a fracture
What orthopedic test is used to evaluate a suspected ACL injury? What structure is eliminated with this test?
Note: may need to update this question later.
Anterior Drawer Test
Hamstrings functions are considered here
Lachman’s test in the acute setting
What injury accounts for half of all knee injuries and has a common incidence?
ACL
A. ACL injuries are more common among in what demographic?
B. What leg is most subject to injury?
A.Female athlete,
Sustained at younger age than males
B. Supporting leg (its kicking leg w/males)
What are the risk factors for an ACL injury?
- Female soccer player,
- Male basketball player
- Valgus moment at the Knee and Adduction moment at the Hip upon LANDING
