LGS 3 Flashcards
An ACL injury is a ______ sprain.
An ACL injury is a LIGAMENT sprain.
Majority of ACL tears are incomplete. True or False?
False.
5-15% are partial, most are full
What are the connection points of the ACL?
Anterolateral part of tibial plateau –> lateral femoral epicondyle
What are the main ways to differentiate muscle strains vs ligament sprains?
Muscle spasm –> ligament sprain has NONE
Pain on contraction –> ligament sprain has NONE
What is the function of the ACL?
- Prevents anterior tibial translation
“X” from ACL & PCL also prevents some rotational forces
What is the incidence of ACL injuries in the US?
1 in 3,500 people
ACL is the most commonly injured ligament in the knee. True or False?
True.
Why are females at a greater risk of ACL injuries than males?
- Muscle imbalance: weaker hamstrings, preferential use of quads while decelerating
- Increased valgus angulation of the knee
- Increased circulating estrogen (controversial)
- Different genetic expression (upregulation of aggrecan and fibromodulin and downregulation of WISP2)
Females are 2-100x at greater risk than males to get an ACL injury. True or False?
False.
there is a 2-10x greater risk.
ACL injuries typically occur in what populations?
- Young (peak age of 17yrs)
- Active individuals
- Participate in sport
What is the etiology of ACL tears?
- Most commonly, non-contact mechanisms
(Decelerating and rotational forces) - Sudden changes in direction, rapid stopping, jumping and landing abnormally, direct blow to lateral aspect of the knee (valgus force)
What athletes/ sports are at highest risk for ACL injuries?
Skiers, soccer players, basketball players, football players
What are some risk factors for ACL injuries?
- Female
- Patella Alta
- Increased tibial slope
- Small notch width index (NWI)
What are some common differential diagnoses for ACL injuries?
- Epiphyseal fracture of femur or tibia
- Medial collateral knee ligament injury
- Meniscal tear
- Osteochondral fracture
- Patellar dislocation
- Posterior cruciate ligament injury
- Tibial spine fracture
What are some ways to diagnose ACL injuries in the clinic?
- Observation,
- ROM,
- Muscle strength testing
- Special tests:
- Anterior Drawer
- Pivot Shift
- Lachman’s test
What are some ways to diagnose ACL tears outside of the clinic?
- MRI (primary modality)
- High Sn (86%) & Sp (95%) - Knee arthroscopy
- To differentiate between partial & complete tears - Arthrography
- Gold standard (92-100% Sn & 95-100% Sp) however rarely used
What is the typical natural history for a complete ACL tear?
Large majority will have surgical repair/ligament reconstruction
(Allograft or autograft)
What are the medium-term (3 months-2 years) risk of instability, meniscal lesion, and osteoarthritis for complete ACL tears?
- secondary instability: 15 -66%
- secondary meniscal lesion: 15 -86%
- osteoarthritis: 30%-100%
What is the natural history of partial ACL tears?
- Good short- & medium-term functional results
- Especially when patients limit their sports activities
- Residual pain is frequent (especially on effort) in patients without subjective instability
- Laxity seems to progress with time
- Low level demand: functional management is indicated
- High level demand: may consider ligament reconstruction
What are some signs & symptoms of ACL tears?
- Hear and / or feel a sudden pop
- Feeling of knee giving way at the time / after injury
- Tenderness along the joint line
- General knee pain
- General knee swelling
- Decreased range of knee motion
- Difficulty walking
Overall, there is a high level of satisfaction with treatment/ surgery of ACL tears. True or False?
True.
When do most patients demonstrate near complete revolution of pain and range of motion limitation after ACL reconstruction?
around 12 weeks
What percentage of patients maintain their preinjury level of play ability 4 years after surgery?
<50%
What are some future risks for individuals who have ACL tears?
- Instability
- Meniscal injury
- Osteoarthritis
