Knee Exam

What are the Ottawa knee rules?

• 55+ yrs old

• Isolated patellar tenderness without other bone tenderness

• Tenderness of the fibular head

• Inability to flex to 90°

• Inability to bear weight immediately after an injury and in the emergency department (4 steps) regardless of limping

What is patella Alta? What can cause it?

• Abnormally elevated patella, higher than normal relative to the femoral trochlea

• Caused by a long patellar tendon or short quad tendon

What is patella Baja? What can cause it?

• Abnormally low-lying patella relative to the femoral trochlea

• Caused by a short patellar tendon or a long quad tendon

What is the consequence of patella Baja?

• Restricted knee ROM

• Crepitations

• Retropatellar pain

What are some potential causes of patellar tilt?

• Muscle imbalances

• Soft tissue laxity

• Bony abnormalities

What are the consequences of having a patellar tilt?

Patellofemoral pain and instability

The acute loss of knee ROM is not a red flag. True or false?

False!

What is a normal amount of a force a healthy adult quad can expel?

0.5-3 Nm/kg

What is a normal amount of a force a healthy elderly adult quad can expel?

0.3-2 Nm/kg

How much force does the quad expel during running?

2 Nm/kg

How much force does the quad need to be able to produce following ACLR for RTS?

3 Nm/kg

How do you calculate torque?

Force output (N) x distance from knee joint center to dynamometer (m)

Describe how the sweep/stroke test is done

2-3 upward strokes on medial side of knee followed by 2-3 downward strokes on the lateral/superior aspect

What would quantify as a score of 0 on the sweep/stroke test?

No fluid movement

What would quantify as a score of trace on the sweep/stroke test?

Small bulge of fluid on medial side of knee

What would quantify as a score of 1 on the sweep/stroke test?

Large bulge

What would quantify as a score of 2 on the sweep/stroke test?

Medial fluid returns without a down sweep

What would quantify as a score of 3 on the sweep/stroke test?

There by so much fluid that there’s no movement

What is the purpose of Lachman’s test?

Test for ACL injury (posterolateral band more specifically)

Describe how Lachman’s test is done. What would a positive result be?

Pt lies supine → PT puts pt’s knee in 30° of flexion → Pt holds pts distal lateral thigh with one hand while the other hand is just below the joint line on the medial tibia/fibula → distal hand provides an anterior translatory force

Positive test is soft or no end feel with increased translation

What are some reasons that you may get a false negative when doing the Lachman’s test?

• Femur not properly stabilized

• Meniscus lesion blocks translation

• Tibia is IR

• Hamstring muscle guarding

What is the purpose of the anterior drawer test?

Test for injury to ACL ligament

Describe how the anterior drawer test is done. What would a positive result be?

• Pt is supine → PT moves pts knee to 90° flex → PT sits on pts foot → PT puts hands around tibia and draws it forward

• Positive test is abnormal amount of movement

What are some reasons for a false negative on the anterior drawer test?

• Hemiarthrosis

• Torn medial meniscus (posterior horn) that is wedged against the medial femoral condyle

• Hamstring guarding

What are some reasons for a false positive anterior drawer test?

• Torn PCL

How is a pt positioned for the posterior sag sign?

Supine with hip flexed to 45° and then knee flexed to 90°

What is the purpose of the reverse Lachman test?

Test for PCL injury/integrity

Describe how the reverse lachman test is done. What would a positive result be?

• Pt is prone on table with knee flexed to 30° → PT stabilizes distal femur against table → PT’s other hand pulls up on tibia

• Positive test is excessive translation

If ya get a positive posterior drawer test, what structures may be hurt?

• Posterior cruciate ligament

• Arcuate-popliteus complex

• Posterior oblique ligament

• ACL

Describe how the quad active test is performed

Knee flexed to 80-90° in neutral rotation → pt tried to use the quad while PT holds ankle down

What is the purpose of the valgus stress test?

Test the injury/integrity of the medial/tibial collateral ligament

Describe how the valgus stress test is performed. What would a positive result be?

• Pt is supine and chill → PT holds lateral distal thigh and medial ankle and provides a valgus force → test is done with knee fully extended and with 20-30° knee flexion

• Positive test is excessive valgus motion

What structures may be injured when you get a positive valgus stress test with the knee fully extended?

• MCL

• Posterior oblique ligament

• Posterior medial capsule

• ACL

• PCL

• Medial quadriceps expansion

• Semimembranosus muscle

What structures may be injured when you get a positive valgus stress test with the knee is in 15-20° flexion?

• MCL

• Posterior oblique ligament

• Posterior cruciate ligament

• Posteromedial capsule

Which position for the valgus stress test is classified as the true test for one-plane medial instability?

When the knee is in 15-20° flexion

What is the purpose of the varus stress test?

Test for injury/integrity of the lateral/fibular collateral ligament

What structures may be injured when you get a positive varus stress test with the knee fully extended?

• Lateral/fibular collateral ligament

• Posterolateral capsule

• Arcuate-popliteus complex

• Biceps femoris tendon

• Posterior cruciate ligament

• ACL

• Lateral gastrocnemius muscle

• IT band

What is the purpose of Apley’s compression test?

Test for meniscus and/or ligamentous pathology

Describe how Apley’s compression test is done

Pt is prone with knee flexed to 90° → thigh is anchored to the examining table with examiner’s knee or hand → PT’s other hand is one the foot and rotating with tibia with distraction first followed by compression

If rotation with distraction is more painful during the Apley’s compression test, what does that mean?

Ligamentous issue

If rotation with compression is more painful during the Apley’s compression test, what does that mean?

Meniscus issue

What is the purpose of Thessaly’s test?

Look for meniscal pathology/tear

Describe how Thessaly’s test is performed. What is a positive test?

• Pt is flat footed while holding onto a table or PT’s hands for balance → Pt flexes knee 5° and rotates femur on tibia 3x while maintaining knee flexion → Pt repeats but with 20° knee flexion

• Positive test is medial or lateral joint line discomfort or locking/catching in knee

What is the purpose of McMurray’s test?

Test for meniscus pathology

How do you assess the lateral meniscus with the McMurray test?

Medially rotate the tibia and extend the knee

How do you assess the medial meniscus with the McMurray test?

Externally rotate the knee and then extend it

What is the point of the joint line tenderness test?

Check for meniscal lesion

What is the purpose of the Patellar Grind test/clark test?

Test for the presence of patellofemoral dysfunction

Describe how the patellar grind test/clark test is done. What is a positive result?

• Pt is supine with their knee extended → PT presses down slightly just proximal to the upper pole or base of the patella with the web of the hand → Pt asked to contract with quads while the PT maintains the downward force

• Positive test is retropatellar pain and pt discontinues the contraction

What is the purpose of the patellar tendon/quad tendon bowstring test?

Determine if pain during squatting or originating from the patellar tendon/quad tendon

Describe how the patellar tendon/quad tendon bowstring test is done. What would a positive result be?

• PT compresses quad or patellar tendon as a pt performs a squat

• Positive is if pain is reduced

What is the purpose of the Hoffa test?

Check for fat pad impingement/pathology

Describe how Hoffa test is performed

PT grabs fat pad just inferior to the patella outside the margin of the patellar tendon with the knee in 30° of flexion while the PT passively extends the knee

What needs to be true in order for the plica/stutter test to be effective?

Need no joint swelling

Describe how the plica/stutter test is performed

Pt is sitting over the edge of the table → PT had a finger of the patella → pt slowly does knee extension and flexion

What would a positive plica/stutter test look like?

Patella stutters/jumps between 60-45° knee flexion

Describe how the patellar apprehension test is done

Pt lies supine with knee flexed to 30° → PT slowly presses patella laterally

What is the purpose of Noble’s compression test?

Check for an irritable distal IT band

Describe how Noble’s compression test is performed. What would a positive result be?

• PT puts pressure on distal IT band while flexing and extending the knee

• Positive test would be pain/snapping or crepitus around 30° of flexion

When doing a posterior glide of the tibiofemoral joint, do you position the tibia in IR or ER?

IR

When doing an anterior glide of the tibiofemoral joint, do you position the tibia in IR or ER?

ER