Knee Flashcards
What does a normal gait require in relation to the knees?
Normal gait requires:
a. flexible and full range knee joints
b. intact supporting ligaments
c. strong quadriceps muscle
d. normal lumbosacral nerve roots
What knee deformities may you note on inspection?
Knee observation from in front, the side and from behind may show these abnormalities:
a. Genu varus (bow legs) may indicate isolated medial compartment disease eg OA, or developmental
b. Genu valgus (knock knees) may indicate inflammatory tricompartment synovitis and cartilage loss, or
developmental
c. Genu recurvatum (hyperextension) indicates hypermobility
d. Fixed flexion deformity may indicate previous synovitis and resolution by fibrosis
e. Popliteal fossa swellings eg Baker’s cyst, popliteal aneurysm, varicose veins, fat pad
What are the four muscles that make up the quadriceps?
The quadriceps muscles of thigh are made up of (lateral to medial):
rectus femoris, vastus lateralis, vastus intermedius, vastus medialis oblique
What is the mechanical function of the patella?
The patella functions primarily as an anatomic pulley for the quadriceps muscle group.
It increases the lever arm of the extensor mechanism allowing for more effective knee flexion and thus
increases quadriceps strength by 33–50%.
What is the minimum amount of fluid that the swipe test can detect?
The swipe test can detect a knee effusion of 10-15 ml
What is the normal range of the knee joint?
Knee joint range of movement is flexion 140 degrees and extension 0 degrees
What muscles are used for knee flexion?
Knee flexion uses the hamstrings muscle group, from lateral to medial:
biceps femoris, semitendinosus, semimembranosus
What are the mechanical functions of the medial collateral ligament of the knee?
The mechanical functions of the medial collateral ligament (MCL) are:
a. primary static stabilizer of the knee and assists in passively stabilizing the knee joint
b. prevents an anterior movement of the tibia and hyperextension
c. joint proprioception
What is the significance of the sag sign?
A positive sag sign indicates a posterior cruciate ligament (PCL) tear and may lead to a false positive anterior
drawer test or Lachman test for ACL tear
What are two indicators of a positive Lachman test?
Lachman test is positive: either significant anterior displacement of the tibia on the fixed femur
or no firm end point is felt
What are common causes of injury of the ACL?
ACL injuries are common in sports:
a. Suddenly slowing down and changing direction (cutting)
b. Pivoting with your foot firmly planted
c. Landing from a jump incorrectly
d. Stopping suddenly
e. Receiving a direct blow to the knee or collision, such as a football tackle
What are other clinical findings in a knee meniscal tear?
Clinical findings in a knee meniscal tear are:
a. joint effusion
b. joint line tenderness
c. inability to squat
d. loss of terminal extension (due to effusion or blocked by torn cartilage
e. positive McMurray’s /Thessaly test
