Examination

ASSESSMENT

Subjective Assessment

  • Mechanism of Injury
    • Position of Foot / Knee
    • Direction of force
  • Initial Symptoms and Progression
    • Degree and location of pain
    • Giving way – due to pain or just gave way
    • Locking
    • Clicks, cracks or pops
    • Sensations of patella moving out of place (or visualisation)
    • Ability to WB
    • How quickly swelling develops – severe swelling within 1-2 hours, versus slowly developing swelling
    • Aggravations and Eases – ie pain behaviour
  • Past Knee History
    • Both that knee and other side, including operations. Note difference between knee RECONSTRUCTION (for ACL tear) and knee REPLACEMENT (for osteoarthritis) – patients often get confused between the two

Objective Assessment

General Considerations

  • In an acute injury:
    • Often everything hurts
    • Weightbearing is usually difficult
    • Active and passive movement is often painful
    • The patient will probably use extensive muscle guarding to prevent further pain
  • This makes assessment difficult and patients should be referred on for followup assessment and treatment advice
  • With assessment of the knee, perhaps more so than any other joint, it is important for the patient to be completely relaxed or the examination will not be accurate.
  • Handling is crucial
  • If no significant laxity is demonstrable initially but you are still suspicious of injury to ACL (eg “pop” or “crack”, giving way) or menisci (locking) arrange appropriate followup (physiotherapy or sports physician) for reassessment once the acute symptoms have subsided.
  • If there is substantial ligamentous laxity, particularly in an extended knee or with a high force mechanism (eg struck by car or kicked by horse) orthopaedic review is vital

Examination

OBSERVATION

  • OBS – HR, BP, TEMP (IF INDICATED)
  • Distal Neurovascular function (pedal pulse, capillary return, sensation, movement, warmth)
  • Swelling
    • Effusion (watery fluid able to be moved between pouches; slow onset)
    • Haemarthrosis (boggy, bloody swelling; rapid onset = usually indicates trauma to ACL, PCL, Menisci, PFJ dislocation or #)
  • Color – is it red?
  • Any Bruising / deformity

FUNCTIONAL TESTS

  • Ability to WB
  • Squat – Bilateral and Unilateral
  • Duckwalk (if able to deep squat without significant pain

GENERAL TESTS

  • Range of motion (Active vs Passive)
  • Flexion / Extension
  • Squat – Bilateral / Unilateral
  • Extension / Abduction
  • Extension / Adduction

SPECIAL TESTS

  • Lateral Stability Tests
    • Valgus Stress Test 0 and 30 degrees
    • Varus Stress Test 0 and 30 degrees
  • AP and PA Stability Tests (Cruciate Ligaments)
    • Lachman’s Test
    • Pivot Shift Test
    • Anterior Drawer Test
    • Posterior Sag Test
    • Posterior Drawer Test
    • Reverse Lachman’s Test
  • Meniscal / Internal Derangement Tests
    • McMurray’s Test
    • Apley’s Grind Test
  • Patellofemoral Joint / Quadriceps Complex
    • Straight Leg Raise
    • Apprehension Test
    • Glides – Medial / Lateral / Superior / Inferior
    • Compression
  • Muscle Length Tests
    • Ober’s Test
    • Hamstrings
    • Quadriceps

Lateral Stability Tests

Valgus Stress Test

Technique

  • Stabilise the patients leg to control hip rotation and knee flexion
  • Apply a valgus (abduction) force to the knee in both full extension and 30 degrees of flexion

Interpretation

  • Pain on the medial side of the knee indicates pathology on opening up of the medial joint space.
  • Laxity of movement indicates more significant damage:
    • Grade I MCL sprain = pain on testing without laxity
    • Grade II = pain with mild laxity
    • Grade III = pain with moderate to significant laxity
  • Laxity only in flexion tends to indicate isolated MCL damage, however if there is laxity in extension as well, this might indicate damage to other structures such as the ACL (the knee is most stable in extension, so if it is now unstable, there is usually more than the MCL damaged)
  • Pain on the lateral side of the knee indicates pathology on closing down the lateral joint space = potential lateral meniscal damage or other internal derangement

Varus Stress Test

Technique

  • Stabilise the patients leg to control hip rotation and knee flexion
  • Apply a varus (adduction) force to the knee in both full extension and 30 degrees of flexion

Interpretation

  • Pain on the lateral side of the knee indicates pathology on opening up of the lateral joint space.
  • Laxity of movement indicates more significant damage:
    • Grade I LCL sprain = pain on testing without laxity
    • Grade II = pain with mild laxity
    • Grade III = pain with moderate to significant laxity
  • Laxity only in flexion tends to indicate isolated LCL damage, however if there is laxity in extension as well, this might indicate damage to other structures such as the ACL (the knee is most stable in extension, so if it is now unstable, there is usually more than the MCL damaged), PCL or posterolateral corner
  • Pain on the medial side of the knee indicates pathology on closing down the medial joint space = potential medial meniscal damage

AP Stability Tests

Anterior Drawer Test

Technique

  • Knee flexed to approximately 90 degrees and stabilise the leg (sit on the foot)
  • Using both hands on the posterior aspect of the tibia, draw the tibia anteriorly.

Interpretation

  • Increased anterior translation and loss of normal endfeel may indicate ACL rupture
  • This test is often difficult in an acutely injured knee and Lachman’s test is significantly more specific and sensitive

Lachman’s Test

Technique

  • With the knee supported in slight flexion, use one hand to stabilise the thigh and the other on the posterior aspect of the proximal tibia
  • Pull tibia forwards

Interpretation

  • Increased anterior movement and lack of firm end feel suggests ACL rupture

Positive Lachman’s Test


Pivot Shift Test

Positive Pivot Shift Test


Posterior Sag Test

Technique

  • With the patient in supine and the knees bent to 90 degrees, place the palm of your hand on the tibia, with the MCP joints at the level of the tibial tubercle
  • If there is posterior sag that is not obviously evident on inspection, this may be a more easier way to detect (the MCPs are particularly sensitive to extension)

Interpretation

  • In a positive test, the MCPs will be more extended than usual, indicating a posterior sag of the tibia and likely PCL injury

Posterior Drawer Test

Technique

  • Knee flexed to approximately 90 degrees and stabilise the leg (sit on the foot)
  • Using both hands on the anterior aspect of the tibia, push the tibia posteriorly.

Interpretation

  • Increased posterior translation and loss of normal endfeel may indicate PCL rupture
  • This test is often difficult in an acutely injured knee
  • Internal derangement may give a false negative
  • Pain alone does not necessarily indicate damage to the PCL

Reverse Lachman’s Test

Technique

  • With the knee supported in slight flexion, use one hand to stabilise the thigh and the other on the anterior aspect of the proximal tibia
  • Push the tibia posteriorly

Interpretation

  • Increased movement and lack of firm end feel suggests PCL rupture

Patellofemoral Joint and Quadriceps Tests

Apprehension Test

Technique

  • With knee in full extension, attempt to pull the patella laterally
  • Can also be tested in knee flexion (30 degrees) but retropatellar force from passive quads tension makes this position more difficult to create a lateral glide naturally
  • Often easier to see change with knee extended as opposed to flexed

Interpretation

  • The test is positive where there is increased lateral excursion, apprehension sign (patient reflexively contracts quadriceps or grabs your arm to prevent patella dislocating), subjective feeling of instability with pain
  • Pain alone does not make a positive test

Active Straight Leg Raise Test


Other Patellofemoral Joint Tests

Technique

  • Attempt to glide the patella medially, laterally, superorly and inferiorly +/- compression through the PFJ

Interpretation

  • Pain with compression and glides usually indicates PFJ dysfunction

Internal Derangement Tests

McMurray’s Test

Technique

  • Begin with knee fully flexed
  • Externally rotate the tibia and extend the knee, applying a valgus force as you extend
  • Repeat with internal rotation / varus


Apley’s Grind Test

Technique

  • Position patient in prone
  • Bend knee to 90 degrees
  • Apply a downward (compressive) force through the foot as you rotate the knee medially and laterally
  • Repeat with upwards (distractive) force

Interpretation

  • Reproducible pain +/- clicking should be worse with compression for meniscal injury / internal derangement


Other Tests

Thompson / Simmonds Test

Technique

  • Have the patient positioned either lying prone or kneeling on the edge of the chair
  • Squeeze the calf muscle

Interpretation

  • If the calf / achilles complex is intact, then the foot should actively plantarflex as the calf is squeezed
  • If the ankle does not plantarflex, this may indicate loss of integrity of the calf / achilles complex



Superior Tibiofibular Joint Stress Test

Technique

  • Attempt to sublux the fibular head anteriorly or posteriorly
  • This can be performed in supine or sidelying

Interpretation

  • If increased movement, pain with assessment or subluxation is possible, this indicates laxity at this joint