(CPA) musculoskeletal knee exam Flashcards
what position and exposure is required for the knee examination?
lying on the couch at a 45 degree angle
knee joint, quadriceps and calf muscles exposed
what are the components of the knee examination?
position & exposure
look
feel
move (active, passive)
special tests
how is movement of the knee joint tested?
active testing
passive testing
which special tests are carried out in the knee examination?
anterior draw for ACL
posterior sag for PCL
medial & lateral collateral ligament
in the ‘look’ component of the knee exam, what are you looking for?
scars (suggest previous trauma/surgery)
muscle wasting
varus knee deformity (bow-legged)
valgus knee deformity (knock knees)
swelling
what are knee scars suggestive of?
previous trauma/surgery of the knee joint
what is knee muscle wasting suggestive of and what must be done if this is observed?
muscle atrophy (maybe due to LMN lesion)
= must do a neurological examination
what is valgus?
lower leg deformity when the bone at the knee joint is angled OUT and therefore the knees ‘knock’ inwards
what is varus?
lower leg deformity when the bone at the knee joint is angled IN and therefore the knees face outwards
what causes knee muscle wasting?
due to disuse (especially if there is chronic pain on movement = arthritis)
in the ‘feel’ component of the knee exam, what are you feeling/palpating for?
temperature
quadriceps tendon
medial and lateral border of the patella
tibial tuberosity + head of the fibula
popliteal fossa
how do you feel for the temperature at the knee joint?
patient lying flat with knee joint exposed
use the back of your hands simultaneously and feel for temperature above the patella, at the patella and below
do it at the same time so you can compare the temperatures
what does a warm knee temperature suggest?
inflammatory condition (e.g. septic arthritis or osteoarthritis)
what does swelling of the popliteal fossa indicate?
Baker’s cyst (fluid-filled swelling of the tissue of the popliteal fossa)
what is a knee effusion?
occurs when excess synovial fluid accumulates in or around the knee joint
why do knee effusions occur?
arthritis
damage to internal structures (e.g. meniscus)
bursitis
which two feel tests are carried out in a knee examination?
patellar tap method
knee sweep test
describe how a patella tap test is carried out
ensure the patient’s knee is extended
slide your non-dominant hand down the thigh to empty the suprapatellar pouch
with the non-dominant hand in place above the knee joint, firmly press over the patella with your dominant hand
(moderate effusion = feel a tap as the patella hits the femur)
describe how a knee sweep test is carried out
ensure the patient’s knee is extended
with your non-dominant hand sweep upward on the medial side of the knee to empty the medial compartment
keeping your non-dominant hand in place, sweep downward on the lateral side of the knee to empty the lateral compartment, with your dominant hand
(small effusion = ripple/bulge of fluid appears on the medial side of the knee from lateral side)
what does the patella tap test detect?
for detecting large effusions
what does the knee sweep test detect?
for detecting small effusions
what is a positive patella tap test?
in moderate effusion = feel a tap as the patella hits the femur
what is a positive knee sweep test?
if small effusion = ripple/bulge of fluid appears on the medial side of the knee from lateral compartment
in the ‘move’ component of the knee exam, what are you moving?
active flexion & extension of the knee joint
passive flexion & extension of the knee joint
which muscles enable flexion of the knee joint?
hamstring muscles
- biceps femoris
- semitendinosus
- semimembranosus
- gracilis
which muscles enable extension of the knee joint?
quadriceps
- vastus medius
- vastus intermedius
- vastus lateralis
- rectus femoris
what can damage to the hamstrings and quadriceps cause?
inability to straight leg raise
how is active movement of the knees assessed?
ensure leg is fully extended to begin with
ask patient to fully flex and then fully extend the knee in turn
how is active movement of the knees assessed?
ask the patient to relax theri legs
you flex and extend the patient’s leg to the maximum extent
!! test the extensor compartment by lifting the patient’s foot with their leg relaxed !!
when assessing movement, which two things do you look for?
pain on movement
range of motion
what does pain on movement of the knee suggest?
damage to the structures (e.g. fracture to the meniscus)
what does a reduced range of motion suggest?
could be due to arthritis
when is the range of motion greater: active or passive movement?
usually passive movement
what is the normal angle of motion for the knee joint?
0-140 degrees
how is hyperextension of the knee joint assessed?
ask patient to relax their leg
lift the patient’s for with the patient’s leg relaxed
what is a normal level of hyperextension?
approx 10 degree
anything above 10 degrees is abnormal
what are the two special tests performed during the knee examination?
anterior drawer test for ACL
posterior sag test for PCL
what does the anterior cruciate ligament (ACL) prevent?
anterior subluxation (i.e. partial dislocation)
what does the posterior cruciate ligament (PCL) prevent?
posterior subluxation (i.e. partial dislocation)
describe how the anterior drawer test is carried out
flex the patient’s knee to 90 degrees and maintain this position (use your thigh when you sit down to stabilise the foot)
check that the hamstring muscles are relaxed and look for posterior sag (posterior subluxation of the tibia on the femur)
with hands behind the upper tibia and both thumbs over the tibial tuberosity, pull the tibia anteriorly
what must you check for before carrying out the anterior draw test and why?
must ensure hamstrings are relaxed AND look for posterior sag (!!)
as posterior sag causes false-positive anterior drawer sign = should not be interpreted as ACL laxity
what result in an anterior drawer test indicates ACL pathology?
significant movement fowards i.e. >1.5cm upwards
indicates an ACL pathology (rupture) often associated with medial ligament injury
movement of how much indicates ACL injury in an anterior drawer test?
> 1.5cm upwards
= indicates an ACL pathology (rupture) often associated with medial ligament injury
what do the medial and lateral collateral ligaments resist?
valgus and varus stresses
describe how to assess the medial collateral ligaments
flex the knee to 30 degrees
place one hand on the medial lower thigh and another hand on the lateral upper calf
apply valgus stress (push out) with your hand on the medial upper thigh
describe how to assess the lateral collateral ligaments
flex the knee to 30 degrees
place one hand on the lateral lower thigh and another hand on the medial upper calf
apply varus stress (push in) with your hand on the medial upper thigh
what does opening of the medial joint line suggest?
opening of the medial joint line suggests damage to the medial collateral ligament
what does opening of the lateral joint line suggest?
opening of the lateral joint line suggests damage to the lateral collateral ligament
what does a positive posterior sag sign suggest?
posterior cruciate ligament tear
what does a positive anterior draw sign suggest?
anterior cruciate ligament tear
what does a positive anterior drawer sign in the present of a positive posterior sag sign indicate?
clinically inconclusive
as positive anterior drawer is a false positive if posterior sag sign present
how do you apply varus stress to the knee joint?
one hand on medial upper calf and another on the lateral lower thigh
using thigh hand, push inwards to apply varus stress
how do you apply valgus stress to the knee joint?
one hand on lateral upper calf and another on the medial lower thigh
using thigh hand, push outwards to apply valgus stress
when varus stress is applied, which ligament is being tested?
lateral collateral ligament
when valgus stress is applied, which ligament is being tested?
medial collateral ligament
