Physical Assessment The Knee
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12-15
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2
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20
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26
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28-29
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31
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41-43
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48-54
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57-64
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85-88
What is a positive McMurray Test?
A click or pop If a click or pop is heard along the medial joint line with valgus stress, external rotation, and leg extension, it suggests a probable tear of posterior aspect of medial meniscus
What is the LCL? How do you palpate it? What does it do?
Also know as the fibular collateral ligament. It connects the lateral femoral condyle to head of the fibula. It is rarely injured. Palpate by crossing one leg over the other so the ankle rests on the knee, find the firm cord that runs from the lateral epicondyle of the femur to the head of the fibula. Protects knee against outward directed force (varus-directed force)
What is the MCL? What does it do?
Also known as the tibial collateral ligament. It is a broad, flat ligament that connects the medial condyles of the femur and tibia. Not easily palpable. It serves to protect the knee against inward acting forces
What are the ligaments of the knee?
Anterior Cruciate Ligament (ACL) Posterior Cruciate Ligament (PCL) Medial Collateral Ligament (MCL; tibial collateral ligament) Lateral Collateral Ligament (LCL; fibular collateral ligament)
What does valgus mean?
Bent inwards e.g. Genu valgum: knock-kneedness
What does varus mean?
Bent outwards e.g. Genu varum: bowleggedness
Where does the ACL begin and end? What does it do?
Crosses obliquely from lateral femoral condyle to medial tibia, preventing tibia from sliding forward on the femur Protects the knee from inward rotation of tibia and limits leg extension to prevent hyperextension
What are the three bones of the knee?
Femur Tibia Patella
What forms the tibiofemoral joints?
Formed by the convex curves of the medial and lateral condyles of the femur as they articulate with the concave condyles of the tibia
What is a positive anterior drawer sign?
Forward jerk showing contours of upper tibia. This suggests an ACL tear. A few degrees of forward movement are normal if equal bilaterally.
Where does the PCL begin and end? What does it do
It crosses the lateral tibia and meniscus to medial femoral condyle Prevents tibia from slipping backward on femur. It is not palpable
What does the McMurray Test do? How is it done?
It tests medial and lateral menisci Pt supine Grasp heel, flex knee Cup hand over knee joint with fingers and thumb along medial and lateral joint line. From heel, rotate lower leg internally and externally. Then, push on lateral side to apply valgus stress on medial aspect of joint At same time, rotate leg externally and slowly extend it.
What does the Lachman Test do? How is it done?
It tests the ACL Place knee in 15 degrees flexion and external rotation. Grasp the distal femur with one hand and the proximal tibia with the other Place thumb of hand on tibia on the joint line Simultaneously move tibia forward and femur back Estimate the degree of forward excursion
What does the anterior drawer sign test? How is it done?
It tests the ACL Pt supine, hips flexed, knees flexed to 90 degrees and feet flat on table. Cup hands around knee with thumbs on medial and lateral joint line and fingers on the medial and lateral insertions of the hamstrings Draw the tibia forward and observe it it slides forward (like a drawer) from under the femur Compare degree of movement with opposite knee
What is the MCC of the injury in the PCL?
MCC injury is rearwards impact-type force on tibial tuberosity while flexed at 90 degrees
What are the three articulations (joints) of the knee joint?
Medial and lateral tibiofemoral joints(Two between the femur and tibia at each condyle) Patellofemoral joint (between femur and patella)
Is the synovial cavity usually detectable?
No, unless it is swollen and tender when the joint is inflammed
Inspection of Knee
Observe gait Alignment, contour, atrophy Normal hollows around patella, swelling Slide 44-46
Focused Hx
Onset of Pain Location of Pain MOI Injury associated events Aggravating/Alleviating factors Hx of previous injury or surgery Slides 35-40
Which one is stronger: the PCL or the ACL?
PCL
What is a positive adduction stress test? What does it mean?
Pain Pain or gap in lateral joint line suggest ligamentous laxity and/or partial tear of LCL.
What is a positive abduction stress test? What does it mean?
Positive if pain (normally, no pain should occur). Pain or gap in medial joint line suggests ligament laxity and partial tear of MCL. Most injuries are medial as opposed to lateral.
What are the bursae of the knee?
Prepatellar bursa Anserine bursa Semimembranosus bursa Slide 34
For palpation, which position allows tendons, ligaments and mm's to relax and make bony landmarks more visible?
Pt sitting, knees flexed and over edge of table
How do you perform the patellofemoral grinding test?
Pt supine, knee extended Push patella against underlying femur Ask pt to tighten the quadriceps as the patella moves distally in the trochlear groove Check for smooth sliding motion
What are the muscle groups of the knee?
Quadriceps femoris (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) Hamstring muscles (semitendinosus, semimembranosus, biceps femoris) Slides 16-18
What is the function of the patella?
Serves as a pulley to aid quadriceps muscle
What is a positive Lachman test?
Significant forward excursion, which suggests ACL tear
What does it mean if patient has pain and crepitus for the patellofemoral grinding test? What if they have pain with patellar movement on quad contraction?
Suggests roughening of patellar undersurface that articulate's with the femur. Similar pain may occur with climbing stairs and getting up from chair. Suggests chondromalacia, or degenerative patella
What does the abduction stress test do? How is it done?
Test MCL Have Pt supine with their knee slightly flexed. Then move their thigh 30 degrees laterally to side of table. Stabilize lateral knee at femur with one hand, while the other holds the medial side of the ankle. Push medially against the knee and pull laterally at the ankle to open the knee joint on the medial side (valgus stress)
What does the Posterior Drawer Sign test? How is it done?
Tests PCL Position same as for anterior drawer sign Push tibia posteriorly Observe degree of movement backward of femur (isolated PCL tears are rare)
What does the adduction stress test do? How is it done?
Tests the LCL Keep position the same as abduction stress test. Switch hands, one medial surface knee and other around lateral ankle. Push medially against the knee, and pull laterally at the ankle to open lateral aspect knee joint (varus stress)
What is the most commonly injured ligament of the knee?
The ACL
What forms the patellofemmoral joint?
The area where the patella slides in trochlear groove on the anterior aspect of the distal femur, during flex/ext of knee.
What is the largest joint in the body?
The knee Slide 3
What is the synovial cavity of the knee? Location? What does it do?
The largest joint cavity of the knee Lies behind concavities on either side of patella, and 6cm above the upper border of the patella, deep to the quadriceps mm in the suprapatellar pouch It covers the medial, anterior and lateral surfaces of knee, and condyles of femur and tibia posteriorly
What are the menisci of the knee? What do they do?
They are crescent-shaped fibrocartilaginous cup-like discs situated on the tibial plateau, located medially and laterally They cushion the action of the femur on the tibia Slide 30
What are the landmarks of the knee?
Tibial tuberosity Adductor tubercle Medial/Lateral condyle Patella Trochlear groove Head of the fiula Slide 8-10
What is the bulge sign used for? How do you do it? What is a positive sign?
Used for minor effusions Have the patients knee extended with your left hand above their knee. Apply pressure on suprapatellar pouch, displacing or "milking" fluid downward. Then stroke downward on medial aspect of the knee and apply pressure to force fluid to lateral area. Lastly, tap knee behind lateral margin of the patella with right hand Positive= fluid wave or bulge on medial aspect of knee b/w patella and femur, consistent with effusion.
What is the balloon sign used for? How do you do it? What is a positive sign?
Used for minor effusions Put thumb and index finger of right hand on either side of patella. The left hand compress the suprapatellar pouch against femur. Then you feel for fluid entering (ballooning into) the spaces next to patella under Right thumb and index finger Positive=palpable wave , returning wave into suprapatellar pouch confirms effusion
What is ballotting used for? How do you do it?
Used to assess large effusions Compress suprapatellar pouch and "ballotte" or push the patella sharply against the femur. Watch for fluid returning to the suprapatellar pouch. Positive= palpable fluid returning into pouch further confirms presence of large effusion, palpable patellar click with compression may occur, but yields more false positives
