1. Examination of The Knee
Kevin Ross
Clinical Educator

2. LOOK Patient standing :- Alignment / symmetry Knee flexion deformity
Valgus deformity
Varus deformity
Popliteal swelling
Alignment/symmetry may be different when weight bearing, than when patient is supine
Knee flexion deformity is the patients knee fully extended? If not ?arthritis could be hip problem also
Or is it in a comfortable position for the patient as some pts have hyperextension (genus recurvatum)
Can be pathological, quadriceps weakened, normal in women. Is it bilateral / unilateral?
Valgus (knock kneed) lateral deviation of the leg below the knee.
Varus (bow legged) medial deviation of lower leg.
Valgus measure distance between medial malleoli of ankle
Varus measure distance between the medial joint lines of the knee
Causes include degenerative or inflammatory processes within the knee, causes excessive wear on one side of the knee. Trauma eg medial collateral ligament = valgus deformity
Popliteal swelling ( bakers cyst) more common in women, result of OA /RA
Causes knee pain and stiffness

3. Alignment / Symmetry
Squat test ask to squat with heels flat on the ground, if unable, indicates incomplete knee flexion, maybe meniscus tear of the posterior horn.

4. Genu Varum / Genu Valgum

5. BAKERS CYST

6. LOOK Patient Supine :- Muscle wasting Scars Bruising Redness Swelling
Rash
Muscle wasting, ask pt to tense quads, note any discrepancy in bulk (atrophy)
Scars, previous surgery,injury healed sinus with tethering indicates previous infection (osteomyelitis).
Bruising indicates superficial structure damage
Redness indicates infection, eg prepatellar bursitis septic arthritis
Swelling is it localised or generalised? Is it within the boundaries of the knee or extended ( ie infection will extend)
Causes include synovitis, pus blood synovial fluid( usually localised)
Rash, psoriasis = RA usual on flexion side of joint

8. FEEL Temperature Tenderness Synovial Thickening
Temperature use back of the hand, feel from mid thigh to mid shin for changes. Feel both legs simultaneously
Tenderness check if in pain first. Feel along the borders of patella,
With knee flexed at 90 degs, (this allows clearer indentification of structures)
palpate along the joint line from the femoral condyles – inferior pole of the patella. Then feel down the inferior patellar tendon – tibial tuberosity
Feel behind the knee for popliteal swelling (bakers cyst) also check for popliteal pulse at this stage.
Synovial Thickening best assessed at the margins of the patella, usually secondary to irritant substance ie- blood, inflammatory arthropathy
localised synovial fold is a plica, can occur anywhere in the joint, caused by trauma, repetition of movement such as cycling.
Synovitis feel posteriorly on both sides of the quadraceps tendon with knee flexed.

9. FEEL Knee Effusion ;- Patella Tap Bulge test
Cross Fluctuation (wipe test)
An effusion can usually be observed, however there are several tests for detecting presence and amount of fluid. Usually causes bulging above the patella (suprapatellar pouch)
Patella tap milk fluid down from the suprapatella pouchusing the first web space between thumb and index finger, use other hand to press down on the patella, if fluid is present the patella will ‘tap’ on the femoral condyles.
Remember to stabilise the patella with thumb and finger or you will get a false negative result.
Bulge Test easiest way of detecting large effusions. Place thumb and finger either side of the patella, push fluid down from the suprapatellar pouch as before. If fluid present will move finger and thumb away from patella.
Cross fluctuation will note presence of small effusions, stroke the medial side of the joint upwards displacing any fluid from the medial compartment, then stroke the lateral side downwards (distally), observe for bulge on medial side if presence of effusion.

11. MOVE Ensure the patient is relaxed, note any pain or discomfort
Compare one knee to the other
Assess full flexion and extension
Assess active movement first
Assess passive movement
Flexion can be limited by the soft tissue of the calf and thigh.
Muscular patients or overweight pts will not be able to flex as much as others
Full flexion is usually no more than 135 degrees ( can use a goniometer to measure angle of flexion if need)
Lack of flexion due to pain, soft tissue injury or arthritis
Extension
full extension recorded as 0 degrees
loss of full ext = neg number eg -10 degrees of fixed flexion deformity
Causes include meniscal injury, arthritis, spasm following injury, particularly if effusion is present
Hyper extension recorded as pos number eg +10 degrees of hyperextension
Examiner places hands under both knees and asks pt to contract their quadriceps muscles, noting equal amount of hyperextension. Can also lift both legs simultaneously from the end of the bed, hyperextension will become obvious.
Common causes can be normal (females), patella – femoral abnormalities, cruciate instability problems, ehlers-danlos syndrome ( affects ligaments etc- stretchy)
Active with the patient in a supine position, ask the patient to flex knee up to their chest and then back down on the couch, assess range of movement.
Ask the patient to keep leg straight and raise off the couch, if cannot keep knee extended = weakened quadraceps or abnormality of the extensors (extensor lag)
Passive place hand on knee whilst flexing knee as far as possible.
Crepitus can be caused by chondromalacia patellae (esp young females), or osteoarthritis

12. Tests for Stability
Anterior draw test (anterior cruciate ligament test)
Flex the knee at 90 deg, sit on the patients foot to stabilise, check the hamstrings are relaxed and check for posterior lag ( subluxation of tibia on the femur) can cause a false positive sign.
Place hands behind upper tibia, thumbs on tibial tuberosity, pull forward, if movement of >1.5cm = ligament rupture. Compare with other knee. Slight movement is normal.
Common injury history of tearing/popping may say the knee came out of joint + goes back in. swelling within 1-2 hrs due to swelling can’t assess immediately
Posterior draw test Posterior cruciate ligament ask the patient to flex knees to 90 degs, look for posterior subluxation from the side. Will note less prominent tibial tuberosity push tibia posteriorly note excessive movement.
Lachman’s test test’s the anterior cruciate ligament, but at 15 – 20 degs one hand stabilises the femur, while the other grips the upper tibia and assess the amount of anterior travel. Can be undertaken sooner after trauma as knee not flexed to 90 degs
Pivot shift test (usually done under general anaesthetic) checks anterolateral instability associated with anterior cruciate ligament instability, leg is extended, hold calf or foot with one hand, twist and push with other. A valgus stress is applied to the knee.
In acl incompetence, lateral tibial condyl is subluxed the knee will reduce at approx 30 degs
Mc Murray test checks for meniscus tears with patient supine, pick up the leg, and flex the knee as far as possible for the patient, place thumb and finger on medial and lateral joint lines of the knee holding the foot with other hand exert external rotation until pain or click is experienced indicating tear over medial joint For lateral lesion repeat but internally rotate the leg.
Medial meniscus is more likely to be damaged. Usually with twisting mechanism whilst load bearing, swelling usally occurs several hours later may experience locking intermittently, pain.
Apley compression test used to diagnose meniscal injury and distinguish it from collateral ligament damage the patient is laid prone with knee flexed to 90 degs, apply pressure through the heel, whilst doing this the leg is rotated internal for lateral meniscus and externally for medial meniscus
Collateral ligament test should be assessed in extension, and at 15 – 20 degs flexion, place one hand on the knee the other holding the ankle and moves the leg from side to side noting stability. There should be no abduction / adduction possible if ligament lax or ruptured will be movement, may experience pain if partially torn but joint will not open.
Medial collateral ligament more likely to be damaged eg hit from side when weight bearing on the leg (rugby tackle)

13. FUNCTION Ask the patient ;- Stand Walk
Stand assess power, gait and co-ordination
Walk look at gait, check for bow legged or knock kneed