NMS Knee (only half)

What structures primarily provide rotational stability of the knee?

The menisci and cruciate ligaments

The cruciate ligaments are named according to what attachment?

Their tibial attachment

What artery commonly tears with an ACL injury?

The middle genicular artery

What is the primary function of the ACL in non-weight-bearing?

Restrains anterior translation of the tibia

What movement does the ACL resist during weight-bearing?

Posterior movement of the tibia

What is the primary function of the PCL in non-weight-bearing?

Restrains posterior translation of the tibia

What movement does the PCL resist during weight-bearing?

Anterior movement of the femur on the tibia

Which collateral ligament is attached directly to the joint capsule?

The MCL

Which collateral ligament protects against valgus stress?

The MCL

Which collateral ligament provides secondary support to the ACL?

The MCL

Which collateral ligament connects the distal femur to the fibular head?

The LCL

Which muscle separates the LCL from the joint capsule?

The popliteus muscle

The popliteus provides secondary support to which ligament?

The PCL

What are the primary functions of the menisci?

Static stability, shock absorption, and rotational movement

Stretching the knee ligaments activates what response?

Neural reflexes causing muscle contraction

What symptoms should always be assessed during a knee history?

Pain, stiffness, locking, swelling, instability, crepitus, numbness, and tingling

What areas should be considered as possible sources of referred knee pain?

The lumbar spine, pelvis, and hip

What factors should always be assessed during the general knee examination?

Trauma, repetitive activities, pain location, swelling, crepitus, and episodes of giving way

What alignment abnormalities should be assessed during inspection?

Valgus, varus, and recurvatum

Ballottement ("bobbing patella") indicates what?

Joint effusion

Joint-line tenderness is highly suggestive of what pathology?

A meniscal tear

Hyperextension commonly causes what injuries?

An isolated ACL tear or patellar dislocation

Hyperflexion commonly causes what injury?

A PCL injury (often associated with an ACL injury)

Sudden deceleration commonly causes what injury?

An isolated ACL tear

A valgus force without rotation commonly injures what structure?

The MCL

A valgus force with rotation on a planted foot commonly causes what injury?

The Unhappy Triad (ACL, MCL, and medial meniscus)

A blow to a flexed knee commonly causes what injuries?

Contusion, fat pad irritation, patellar fracture, or PCL injury

Running with repetitive mid-range knee flexion commonly causes what?

IT band syndrome or popliteus tendinitis

Repetitive jumping or sprinting commonly causes what?

Patellar tendinitis (jumper's knee)

In adolescents, repetitive jumping commonly causes what condition?

Osgood-Schlatter disease

Constant squatting commonly predisposes patients to what injury?

A meniscal tear

Constant valgus stress commonly causes what?

MCL injury or pes anserine tendinitis

What is the classic mechanism of a meniscal tear?

Twisting on a planted foot while the knee is flexed

Deep squatting under load commonly injures what structure?

The meniscus

Meniscal injuries commonly occur with what ligament injury?

ACL tears

What is another name for the Unhappy Triad?

The Triad of O'Donoghue

What structures make up the Unhappy Triad?

ACL tear, MCL tear, and medial meniscus tear

What are the classic symptoms of a meniscal tear?

Localized joint-line tenderness, pain and swelling with loading, difficulty twisting or squatting, locking, and inability to fully extend the knee

What examination finding is classically associated with a meniscal tear?

A positive McMurray test with a painful clunk

What is the initial treatment for a meniscal tear?

RICE and NSAIDs

When should a patient with a meniscal tear be referred?

If the knee is locked or unstable

When are radiographs indicated for a meniscal injury?

When there is associated trauma

What imaging modality is best for diagnosing a meniscal tear?

MRI

Which meniscal tears are most amenable to surgical repair?

Large peripheral tears

According to the lecture, meniscal tears greater than what size are unlikely to heal?

Greater than 1 cm

Apley Compression Test

External rotation reproduces pain in a medial meniscus tear; internal rotation reproduces pain in a lateral meniscus tear

McMurray Test

Painful click or snap indicates a meniscal tear. Internal rotation tests the lateral meniscus; external rotation tests the medial meniscus

Payr Sign

Pain on the medial side while in the lotus position indicates a posterior horn tear of the medial meniscus

Thessaly Test

Pain, joint-line discomfort, locking, or catching while standing on one leg with the knee flexed to 20° indicates a meniscal tear

Dynamic Test

Pain under the examiner's finger or sharp pain during the maneuver indicates a lateral meniscus tear

Bounce Home Test

Failure to achieve full knee extension indicates a torn meniscus

Childress Duck Waddle Test

Pain, inability to fully squat, or posterior clicking indicates a meniscal tear. Internal rotation stresses the medial meniscus; external rotation stresses the lateral meniscus

Steinmann Sign

Joint-line tenderness that moves posteriorly during knee flexion indicates a meniscal tear

Which tests are considered the best clinical tests for ruling in or ruling out a meniscal tear?

Joint-line tenderness, McMurray test, and Thessaly test

Which ligament injuries are most commonly associated with lateral impacts?

MCL injuries

Which ligament is most commonly injured in non-contact pivoting or off-balance landing injuries?

ACL

A blow to the anterior knee commonly injures which ligament?

The PCL

Which collateral ligament injury is the least common?

<1% are LCL injuries

What are the classic signs and symptoms of an ACL tear?

Audible pop, immediate swelling, difficulty achieving full extension, hemarthrosis, positive Lachman test, and positive anterior drawer test

Approximately what percentage of hemarthrosis cases are caused by ACL tears?

About 75%

Lachman Test

Soft or mushy end-feel with increased anterior translation (infrapatellar pole disappears); indicates ACL insufficiency, posterior oblique ligament injury, or arcuate complex injury

Why is the Lachman test preferred over the anterior drawer test in acute ACL injuries?

Because hamstring spasm at 90° knee flexion can limit the anterior drawer test

Anterior Drawer Test

Anterior translation greater than 6 mm indicates anterior cruciate insufficiency

The Anterior Drawer Test is most useful for diagnosing what?

Chronic ACL tears rather than acute ACL tears

What amount of anterior tibial translation is considered normal during the Anterior Drawer Test?

Approximately 6 mm

Lateral Pivot Shift Test

Reduction ("jog") of the tibia with a sensation of giving way indicates ACL injury, posterolateral capsule injury, arcuate-popliteus complex injury, LCL injury, or IT band involvement

Losee Test

A clunk just before full extension indicates anterolateral rotary instability

What mechanism of injury commonly causes anterolateral rotary instability?

A posterior force on a planted foot with internal rotation

Slocum Test

Excessive anterior movement with the foot internally rotated indicates anterior rotatory instability; excessive posterior movement indicates posterior rotatory instability (cruciate instability)

Which three orthopedic tests are best for ruling IN an ACL tear?

Anterior Drawer Test, Lachman Test, and Lateral Pivot Shift Test

Which orthopedic test is best for ruling OUT an ACL tear?

Lachman Test

What is the classic orthopedic test finding in a PCL injury?

A positive Posterior Drawer Test

In a minor PCL injury, where is the tibial plateau located?

Level with the femoral condyles

In a severe PCL injury, where is the tibial plateau located?

Posterior to the femoral condyles

Posterior Drawer Test

Excessive posterior translation of the tibia indicates PCL injury

Posterior Sag Sign (Godfrey Tibial Sag Sign)

Posterior subluxation of the tibia that reduces with an anterior force indicates a significant PCL injury

What are the classic examination findings of MCL and LCL injuries?

Localized tenderness and positive valgus or varus stress tests

Grade I knee ligament sprain

Incomplete stretching of ligament fibers with minimal pain, minimal or no swelling, no instability, and no loss of function

Grade II knee ligament sprain

Partial ligament tear with moderate pain, moderate swelling, some loss of function, and some instability

Grade III knee ligament sprain

Complete ligament rupture with marked pain, swelling, instability, and loss of function

Abduction Stress Test

Also called the Valgus Stress Test; stresses the MCL and is performed at both 0° and 30° of knee flexion

Adduction Stress Test

Also called the Varus Stress Test; stresses the LCL and is performed at both 0° and 30° of knee flexion

What does pain without instability during valgus or varus stress testing indicate?

A Grade I collateral ligament sprain

What does pain with joint opening but a definite endpoint indicate during valgus or varus stress testing?

A Grade II collateral ligament sprain

What does joint opening without a definite endpoint indicate during valgus or varus stress testing?

A Grade III collateral ligament sprain

What is the initial treatment for collateral and cruciate ligament injuries?

RICE and NSAIDs

What imaging should be obtained after significant collateral or cruciate ligament injuries?

Radiographs to rule out fracture, followed by MRI if indicated

When should an ACL injury be referred?

Orthopedic referral

How are low-grade PCL injuries typically managed?

Conservative treatment

When should a PCL injury be referred?

Severe PCL injuries

Why are LCL injuries frequently managed surgically?

Because they commonly occur in conjunction with cruciate ligament injuries

What ligament injury is commonly associated with valgus stress without rotation?

MCL injury

What ligament injury is commonly associated with valgus stress and rotation?

ACL, MCL, and medial meniscus (Unhappy Triad)

What ligament injury is commonly associated with hyperextension?

ACL injury

What ligament injury is commonly associated with hyperflexion?

PCL injury

What ligament injury is commonly associated with sudden deceleration?

ACL injury

What ligament injury is commonly associated with a direct blow to the anterior aspect of a flexed knee?

PCL injury