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**
Meniscus injury PE test:
-also, what do Pts complain of?
McMurray
-**Pts may experience “locking in extension” – piece/flap of meniscus obstruction joint
“Pt has medial joint line tenderness”
think Meniscus tear!!!
Meniscus injury Dx:
-Xrays usually normal but may show joint space narrowing or effusion
More helpful in pts wo h/o OA
-MRI is TOC (test of choice)
Meniscus injury Tx:
- Degenerative tears – non-operaple, PT
- Acute tears: arthroscopic meniscus repair or debridement
Knee dislocation: dislocation of the _________ joint of the knee
tibiofemoral
Knee dislocation is considered an orthopedic _______
EMERGENCY!!
Stats about knee dislocation: (etiology)
- The exact incidence is unknown as many present already reduced
- Associated with multi-trauma in almost half of patients
**Ppl are screaming in pain
How is a knee dislocation described?
Described in terms of the tibia’s displacement relative to the femur
To dislocate the knee, at least __, of the ___ major knee ligaments are torn
3, if not all, of the 4
Knee can dislocate in 3 ways (list 3)
Can dislocate anteriorly (31%) or posteriorly (25%), laterally (13%), or medially (3%)
Which artery sustains either partial or complete disruption in 40% of knee dislocations?
The popliteal artery, which courses through the popliteal fossa, sustains either partial or complete disruption in 40% of knee dislocations–>** vascular emergency!!!!
the ______ nerve is injured in 23% of knee dislocations
The peroneal nerve, which provides sensation to the lateral side and dorsum of the foot and controls ankle dorsiflexion
Knee dislocation MOI:
MC with high-energy trauma such as hyperextension (anterior dislocation), or anterior blow to the knee (posterior dislocation) - dashboard injuries
Knee dislocation PE findings
-Gross deformity (if no spontaneous reduction)
-Large effusion
-Significant pain – unable to bear weight
-**MUST evaluate for neurovascular injuries!–> Palpable distal pulses – does NOT exclude the
possibility of a vascular injury!
What MUST you order for a knee dislocation?
**Obtain Ankle-Brachial Index –> assessing Popliteal vasculature
What else should you assess in a person with suspected knee dislocation?
- Assess pt sensation and strength
- -evaluating the Peroneal Nerve (provides sensation to the dorsum of the foot and controls ankle dorsiflexion)
ABI’s: what is the cut off for ordering a CT arteriogram?
- Systolic BP in LE (“ankle”) / systolic BP in the UE (“brachial)
- ABI >0.9–> monitor with serial exams
- ABI <0.9 –> obtain advanced imaging to evaluate the popliteal artery
**Intact distal pulses is NOT sufficient enough for acute knee injuries!
Imaging for knee dislocations
- AP and lateral knee xrays–>Obtain even if self reduced to evaluate for tibial plateau fracture
- *CT arteriogram ( IS gold standard!!) or arterial duplex ultrasound
-**MRI later to evaluate for ligamentous derangement
Why is CT arteriogram gold standard for eval. knee dislocations?
- Evaluates for popliteal artery injury
- Not necessarily always indicated – but do obtain if any doubt!
-Absolutes: PE consistent with decreased circulation or ABI <0.9
Knee dislocation tx:
- IV pain control – often admitted for this alone!
- Reduce – even if pt has a vascular injury – reduce than reassess and obtain ortho/vascular consult and advanced imaging
- Post-reduction xray
- Splint in a long leg splint with 20-30 degree flexion
- Admit for pain control and serial exams with ortho consult
Knee dislocation –complications (which one is MC?)
- Limb ischemia
- Permanent nerve damage
- Compartment syndrome
- Arthrofibrosis (stiffness) – most common
Knee dislocation: what must you do prior to ordering an X ray?
REDUCE!! then reassess and obtain ortho consult and advanced imaging
Knee dislocation –Prognosis
- Patients will require an MRI after swelling has reduced – will likely need surgical repair for ligamentous injuries
- Patients need to know that complications are frequent and rarely does the knee return to its pre-injury state
Knee bursitis- describe this condition
Bursa becomes irritated and produces too much fluid, which causes it to swell and puts pressure on the adjacent parts of the knee
MC location for knee bursitis?
- **Pre-patellar most common (KNOW!) – direct pressure on the knee
- -“Housemaids knee”
Knee bursitis Sxs:
- Swelling and tenderness over the bursa
- May become infected – erythema, warmth
Knee bursitis dx:
dx is clinical
Knee bursitis Tx
- NSAIDs
- RICE
- Eliminate pressure over the patella
- Refractory – prepatellar bursa injections
Knee osteoarthritis is ___x more common than hip osteoarthritis
3x
knee OA demographic:
- Affects 1/3 of those over age 65 years
- *Chronic progressive knee pain – medial compartment more commonly affected
Knee OA Sxs:
- Morning stiffness lasting < 30 minutes (KNOW!!)
- Crepitus
- Mild effusion
- Pain relieved with rest
-*Severe - Genu Valgum (knock knee) or Genu Varum (bow leg)
Knee OA dx:
Xrays – joint space narrowing, osteophytes
Knee OA tx:
- Conservative: Weight loss (for those with BMI >25), graded exercise (quad strengthening)
- APAP and NSAIDs
- Intra-articular Corticosteroid - Offers short-term relief, but does not improve quality of life, and may result in greater cartilage loss
-Synvisc (Hyaluronic acid) - Intra-articular viscosupplementation
(Mixed data)
- Platelet-Rich Plasma Injections (Mixed data)
- Total or partial knee replacement
Patella Subluxation & dislocation: how common? Which direction is MC?
- Very common injury
- Can go medially or lateral (laterally more common)
MOI Patella Subluxation & dislocation
direct blow to the side of the knee
Patella Subluxation & dislocation Sxs:
- Pain, swelling, deformity
- Limited ROM, often locked in extension
Patella Subluxation & dislocation dx:
Xray
Patella Subluxation & dislocation tx:
- Reduction – apply pressure while extending the knee
- Immobilization short-term
- PT – quad strengthening
- Non-op after first, op if recurrent
Patella Fracture MOI
-Direct patellar impact
ie Dashboards, fall onto flexed knee
Patella Fracture Sxs:
Usually significant swelling and focal pain
Patella Fx Dx:
-Xray – AP, lateral, and sunrise views (KNOW!)!
- Multiple fracture types
- Important to examine and document an intact extensor mechanism (patellar tendon intact)
- SLR(straight leg raise)
Patella fx tx:
- Ortho referral, RICE, pain control
- Non-operative: extensor mechanism intact, nondisplaced fx, vertical fracture
- -**Extension bracing WITH weight bearing
- Operative: extensor mechanism failure, open fx, displaced fx, comminuted fx
- ORIF (Open reduction and internal fixation) surgery
Bipartite patella: describe this condition and how common
- In about 1 in 50 people the patella is composed of two bones
- This is a bilateral abnormality in 50% of people
- Correlate xray findings with PE, consider obtaining bilateral imaging
- Weight-bearing (squatting) view demonstrates increased separation of fragments compared with non-weight views (prone)
Patellar tendon rupture: how common? and MOI?
Not super common
MOI: sudden quadriceps contraction with knee in a flexed position (e.g., jumping sports, missing step on stairs)
Patellar tendon rupture Sxs:
pain, swelling, elevation of patella
Patellar tendon rupture dx:
Xray shows patella displacement–> MRI
Patellar tendon rupture tx:
- Ortho referral
- Complete tears are repaired operatively
Chondromalacia /Patellofemoral syndrome aka ______
“runners knee”
Chondromalacia /Patellofemoral syndrome: describe this condition
=Damage to the undersurface cartilage of the patella secondary to poor patellar tracking
-Women > Men, adolescents/young adults
Chondromalacia /Patellofemoral syndrome: sxs
- Chronic, progressive anterior knee pain
- Progressive pain that is increased with going up stairs and/or squatting
- No effusion
- Grind test and apprehension sign
Pts with Chondromalacia /Patellofemoral syndrome are at increased risk of ______ ______ ______
lateral patella subluxation
Chondromalacia /Patellofemoral syndrome dx:
- Xrays – AP, lateral, and sunrise (bilateral)
- -Patella alta/baja, or lateral patella tilt
- MRI – assess cartilage damage
Chondromalacia /Patellofemoral syndrome tx:
- Non-operative is mainstay
- NSAIDs, PT (quad strengthening)
- Operative if persistent/progressive > 1 yr and PT failed
- -Arthroscopic debridement
- -Patellar realignment surgery
