Knee Examination

The examination of the knee is a key musculoskeletal examination to master. It is commonly tested in OSCE exams and more importantly, if you end up working in general practice or in the emergency department, chances are you will need to be able to distinguish between a simple strain and damage to key ligaments. In this section we will cover how to assess the knee joint using a systematic approach.

Wash hands

  • Wash your hands using the Ayliffe technique

Introduce yourself

  • Introduce yourself and give your name and grade

“Hi, my name is Han Solo and I am a 4th year medical student”

Check patient details

  • Clarify patient's identity by confirming their name and asking for their DOB

Describe examination

  • Explain what examination you are performing and what this involves

“I have been asked to examine your knee today. This involves having a look, a feel and asking you to do a few exercises.”

Gain verbal consent

“Would this be ok with you?”

Expose appropriately

  • Fully expose the patient's knee

Reposition

  • Ensure the patient is standing for the purposes of this examination

General end of bed inspection

  • Mobility aids such as wheeled walkers, zimmer frames or walking sticks
  • Evidence of injury/trauma

Inspect Gait

  • Symmetry and smoothness
  • Gait cycle - stance and swing phase
  • Abnormal gait - Ataxic (cerebellar disease), Antalgic (trauma/OA), waddling    
  • (proximal muscle weakness), shuffling ( Parkinson’s disease)

Knee inspection anterior and posterior (standing)

  • Check alignment - valgus deformity (knock-knee) or varus deformity (bow-leg)
  • Symmetry
  • Muscle wasting
  • Popliteal swelling - Baker’s cyst, aneurysm or abscess.

Ask the patient to lie on the bed and further inspect the knees

  • Skin changes - erythema (cellulitis), plaques (psoriasis)
  • Fixed flexion deformity
  • Swelling - effusion, septic joint, inflammatory arthropathy
  • Scars - evidence of previous surgery or injury


NB - Remember to talk through what you are doing, both for the sake of the patient (bit awks to just stare at people’s body parts for extended periods of time) and the examiner.

“I am just going to be checking your knee to make sure it has a nice normal alignment, and also ensuring there are no swellings or skin changes.”

Start with the patient lying down in the bed with the knees exposed

NB - Ask the patient before starting if they have any pain in their knee. When feeling the patient’s knee ask them to let you know if there is any pain when you palpate.

Assess temperature

  • Check for the temperature around the knee joints using the back of your hand

Check for effusion

  • Usually done by performing a patella tap
  • This involves running one hand down the patient’s thigh towards the knee
  • Which results in an effusion being forced behind the patella
  • With three fingers of the other hand push the patella down gently
  • Positive test is when the patella bounces back and cause a tap

Knee joint palpation

  • Flex the knee to 90°
  • Palpate for tenderness and evidence of swelling along the joint line
  • Starting at the femoral condyles moving down towards the inferior pole of the patella
  • Then continue down the inferior patella tendon to the tibial tuberosities
  • Work you way to the back of the knee feeling for any swellings (Baker’s cyst)

NB - Most clinicians will start with the good knee first. Both building trust with the patient and also giving you an idea what the good side feels like.

Assess active movement

  • Ask the patient to bend their knees one at a time (Flexion 140°)
  • Ask them to then straighten their knees again (Extension)

Assess passive movement

  • Place one hand on the knee and repeat the same movements
  • Important to make sure the patient is relaxed
  • Take note of any crepitus, locking or reduction in the movements

“ Now I will be doing the same movements, but I just need you to relax and let me take the full weight of your leg.”

“Relax and can you make your leg go nice and floppy?”

Look for evidence of hyperextension

  • Place the palm of your hand on the patient’s heel and lift leg
  • Look for any hyperextension >10° (hypermobility or collagen disorder)

Anterior draw test (Anterior cruciate ligament) and Posterior draw test (Posterior cruciate ligament)

  • Flex the patient’s knee to 90°
  • Check for evidence of posterior sag or step-back of tibia from the side of the knee
  • Wrap both hands around upper tibia
  • Place thumbs on tibial tuberosity and index fingers in the popliteal fossa           
  • Stabilise lower tibia with forearm
  • Gently pull forward
  • Gently push backwards

NB - Significant movement forward indicates ACL laxity or damage and likewise significant backward movement indicates PCL laxity or damage.

Medial and lateral collateral ligament

  • Hold the knee flexed at 15°
  • Hold ankle with one hand and the knee with the other
  • Apply pressure to the lower tibia on the medial and then the lateral aspect of the knee

NB - Remember you are testing the ligament opposite to the pressure area. For example, if you are applying pressure to the medial aspect of the knee and notice excessive movement then it likely indicates lateral collateral damage.

Thank patient

  • Let the patient know you have finished examining them and thank them for their time. Be courteous and offer them help to get redressed.

“That’s the end of the exam. Thank you for your time. Would you like any help getting dressed?”

State other exams for completion

  • Turn to the examiner and state what else you would do to complete the exam.

“To complete the examination I would examine the ankle and the hip joints as well as conducting a full lower limb neurological assessment.”

State what investigations you would perform

  • Explain to the examiner what tests and investigations you would perform based on your findings and the patient’s history;
  • Xray

  • MRI