Lower Extremity Orthopedics- Jaynstein- Exam 2 Flashcards
What is the largest joint in the body?
KNEE! susceptible to injury from trauma, inflammation, infection, and degenerative changes
The knee is stabilized by 4 ligaments: (list them)
- Against anterior movement by the anterior cruciate ligament (ACL)
- Against posterior movement by the posterior cruciate ligament (PCL)
- Against varus strain by the lateral collateral ligament (LCL)
- Against valgus strain by the medial collateral ligament (MCL)
The ACL connects the posterior aspect of the _____ _____ to the anterior aspect of the _____
- femoral condyle
- tibia
ACL function?
Controls anterior translation of the tibia on the femur as well as rotational stability
How common is an ACL injury?
Common injury! - particularly in sports (3% of all athletic injuries)
Soccer, basketball, football and skiing
*Women > Men
MOI: ACL
- Typically in a non-contact deceleration, producing valgus twisting
- -Hyperextension
- -Marked internal rotation
- Or with Pure deceleration (MC mechanism is from stopping suddenly)
Varus?
think R for rum, rum makes your knees widen (Varus= knees wide apart)
-varus strain=LCL
Valgus?
think G for gum (gum makes your knees stick together)
-Valgus strain= MCL
ACL injury Sxs:
- “pop”
- Marked, immediate effusion
- Difficulty/inability to weight bear
- Knee feels “unstable”
ACL injury PE findings: (tests you will perform)
- Lachman’s, Anterior Drawer
- Lever Sign
ACL injury Dx:
- what does the Xray show?
- ____ fractures are present in 75% of ACL tears**
- 1st line imaging study for ACL tears?
- Knee xrays often show a large effusion
- Can demonstrate a Second fracture–> avulsion fx of the lateral tibial plateau
- *Present in about 75% of ACL ruptures
TOC: MRI without contrast – large effusions can obscure imaging
ACL injury tx:
- Young/active with complete tear –->surgical repair–>Autograft (own patellar or hamstring tendon) or allograph (cadaver)
- Older/sedentary or partial tear – conservative. –>PT to strengthen the hamstrings, bracing
ACL injury additional tx? (specify for acute and subacute/chronic)
- Bracing (debated) to protect other structures – pt at increased risk of secondary meniscus injury
- Acute: knee immobilizer and crutches
- Subacute/chronic: hinged brace
- RICE, Pain control, & Ortho referral
What is the strongest ligament in the knee?
PCL (posterior cruciate ligament)
T/F: complete tears are more common than partial tears with the PCL
False! Sprains or partial tears are more common than complete tears
–Complete tears are associated with major trauma
Over ____% of PCL tears have assoc. injuries
-over 70%, ACL and MCL tears MC, or complete knee dislocation
MOI: PCL injury
- Often due to a blow to the knee while it’s flexed
- ie Striking the knee against the dashboard during an auto accident
- ie Falling on the knee while it’s flexed
PCL injury Sxs:
- Swelling is immediate and typically profound
- Severe pain
- Limited ROM
- Instability, inability to ambulate
PCL injury Dx:
- **“sag sign” – obvious set-off of the tibia posterior
- Posterior drawer test
- MRI WITH CONTRAST (now you’re concerned about vascular disruption)
PCL injury tx: (are these Pts admitted?)
-when do you opt for Physical therapy vs surgery?
- Ortho referral – often admitted!
- RICE, pain control, immobilization with crutches
- Isolated PCL tears may be treated non-op with PT (failure = surgery)
-In combo with other injuries usually means operative treatment
What is the MC injured ligament in the knee?
MCL (medial collateral ligament). – however, not all pts with an MCL injury get seen
What are MCL injuries often associated with?
concurrent ACL injury
The MCL and LCL are extra-articular, and therefore ____ ______ is less common with these injuries
joint effusion
MOI MCL:
-Valgus stress on a partially flexed knee
-Lateral to medial impact
(Pt will say something hit the side of their knee, focal pain)
MCL Sxs:
- Focal pain over ligament
- Minor swelling
- Limited ROM acutely – improves quickly! In about 2 weeks
MCL injury Dx:
- Valgus stress exam
- -Causes pain and laxity
- MRI – does not need to happen acutely – may watch and wait
MCL injury Tx:
- Graduated weight bearing as tolerated
- Bracing (minor hinged, severe immobilizer)
- PT
- Allow 6-8 weeks for healing
- Isolated MCL tears rarely need surgery
LCL (lateral collateral ligament injury) injury: how common?
-is there joint effusion?
- less commonly injured
- The LCL is extra-articular and therefore, joint effusion is less common with these injuries
LCL MOI:
- Varus stress on a partially flexed knee
- Medial impact
LCL injury Sxs:
- Focal pain over ligament
- Minor swelling
- Limited ROM acutely – improves 2 wks
LCL injury dx:
- Varus stress exam–>Causes pain and laxity
- MRI – does not need to happen acutely – may watch and wait
LCL injury tx:
- Ortho referral – often surgical
- Brace
Meniscus injuries: how common?
- “Shock absorbers” of the knee
- **Very commonly injured
- Can be injured acutely or suffice to degeneration
Meniscus MOI:
**multiple mechanisms, usually twisting related
-Internal rotation of femur on tibia with knee in flexion (catches posterior meniscus between femur and tibia)
-Sudden extension causes longitudinal tear (external rotation for lateral meniscal injury)
-May have partial or complete tear, posterior or anterior horn tear, longitudinal or bucket handle tear
(dont memorize these types)
Meniscus injury Sxs:
- “catching,” “locking,” “clicking”
- Painful walking and squatting
- Mild to mod joint swelling
- ** (KNOW)->Joint line tenderness**