Knee examination – OSCE Guide

Knee examination frequently appears in OSCEs. You’ll be expected to pick up the relevant clinical signs using your examination skills. This knee examination OSCE guide provides a clear step by step approach to examining the knee, with an included video demonstration. Check out the knee examination mark scheme here.

Introduction

Wash hands

Introduce yourself

Confirm patient details – name/DOB

Explain examination:
“Today I need to examine your knee joint, this will involve looking, feeling and moving the joint.”

Check understanding and gain consent:
“Does everything I’ve said make sense?  Are you happy for me to examine your knee joint?”

Expose patient’s legs – ideally, the patient should be wearing shorts

Position the patient standing upright

Ask if patient currently has any pain

Look

Inspect for mobility aids and adaptations – walking stick / wheelchair

Gait

Is the patient demonstrating a normal heel strike/toe off gait?

Is each step of normal height? –high-stepping gait is noted in foot drop (secondary to common peroneal nerve palsy / sciatic nerve palsy i.e after total hip replacement)

Is the gait smooth and symmetrical?

Any obvious abnormalities? – antalgia / waddling / broad-based

Inspect the knees

Anteriorly

Scars – previous surgery / trauma

Swellings – effusions / inflammatory arthropathy / septic arthritis

Asymmetry/leg length discrepancy

Valgus or varus deformity

Quadriceps wasting – reduced mobility secondary to injury / arthritis / nerve injury

Posteriorly

Scars

Asymmetry

Popliteal swellings – Baker’s cyst / Popliteal aneurysm

Feel

Ask the patient to lay on the bed.

Assess temperature – ↑ temperature may suggest inflammation/infection

Palpation of knee and surrounding structures (with leg straight and relaxed)

• Quadriceps tendon – tenderness may suggest tendonitis
• Patella – palpate the medial and lateral patella facets for tenderness (stabilise one side of patella and palpate with fingertip on the other) – tenderness may represent injury / patellofemoral arthritis 

Assess for joint effusion

Joint effusion can be caused by ligament rupture (e.g. anterior cruciate ligament), septic arthritis, inflammatory arthritis and osteoarthritis.

Patellar tap (for large joint effusions)

1. Empty the suprapatellar pouch by sliding your left hand down the thigh to the patella.

2. Keep your left hand in position and use your right hand to press downwards on the patella with your fingertips.

3. If there is fluid present you will feel a distinct tap as the patella bumps against the femur.

1. Position the patient supine, leg relaxed and straight.

2. Swipe fluid from the medial part of the knee into the suprapatellar pouch.

3. Hold the fluid in the suprapatellar pouch with one hand on the medial side.

4. Swipe down from the suprapatellar pouch on the lateral side with the other hand.

5. The appearance of a bulge or ripple on the medial side of the joint suggests the presence of an effusion.

Palpation of knee and surrounding structures (with knee bent to 90°)

• Patella tendon – tenderness may suggest tendonitis
• Tibial tuberosity – tenderness may suggest Osgood-Schlatter disease
• Joint line – tenderness may suggest a meniscal tear
• Head of the fibula
• Collateral ligaments (medial and lateral)
• Popliteal fossa – feel for any obvious collection of fluid (e.g. Baker’s cyst)

Measure quadriceps circumference and compare – 20cm above tibial tuberosity – allows detection of subtle muscle wasting

Move 

Active

This involves the patient performing the movement. Ensure you observe for restricted range of movement and signs of discomfort.

Knee flexion – normal ROM 0-140º – “Move your heel as close to your bottom as you can manage”

Knee extension – “Straighten your leg out as best as you are able to.”

Passive

This involves the patient relaxing and allowing you to move the joint freely. It’s important to feel for crepitus as you move the joint and observe any restriction of movement.

Knee flexion and extension

Hyperextension –  elevate both legs by the heels – note any hyperextension (<10º is normal)

Special tests

Anterior/Posterior drawer test

1. Flex the patient’s knee to 90º

2. Inspect for evidence of posterior sag as this can give a false positive anterior drawer sign

3. Wrap your hands around the proximal tibia with your fingers around the back of the knee

4. Rest your forearm down the patient’s lower leg to fix its position

5. Position your thumbs over the tibial tuberosity

6. Ask the patient to keep their legs as relaxed as possible (tense hamstrings can mask pathology).

7. Pull the tibia anteriorly and feel for any anterior movement of the tibia on the femur –  significant movement may suggest anterior cruciate laxity/rupture

8. Push the tibia posteriorly  –  significant movement may suggest posterior cruciate laxity/rupture

With healthy cruciate ligaments, there should be little or no movement noted.

Lachman’s Test (most sensitive test for ACL rupture)

1. Flex the patient’s leg to 30°

2. Hold the lower leg with one hand with the thumb on the tibial tuberosity and the fingers on the calf

3. With the other hand hold the thigh just above the patella

4. Use the hand holding the lower leg to pull the tibia forward on the femur while the other hand stabilises the femur

Significant anterior movement of the tibia on the femur signifies anterior cruciate ligament laxity/rupture.

Collateral ligaments

Lateral collateral ligament (LCL)

Below are instructions to examine the right knee – change your hands for the left knee

1. Extend the patient’s knee fully.

2. Hold the patient’s ankle between your elbow and side.

3. Place your right hand along the medial aspect of the knee.

4. Place your left hand on the lower limb (e.g. calf or ankle).

5. Push steadily outward with your right hand whilst applying an opposite force with the left.

6. If the LCL is damaged your hand should detect the lateral aspect of the joint opening up.

Medial collateral ligament (MCL)

Below are instructions to examine the right knee – change your hands for the left knee

1. Extend the patient’s knee fully.

2. Hold the patient’s ankle between your elbow and side.

3. Place your right hand along the lateral aspect of the knee.

4. Place your left hand on the lower limb (e.g. calf or ankle).

5. Push steadily inward with your right hand whilst applying an opposite force with the left.

6. If the MCL is damaged your hand should detect the medial aspect of the joint opening up.

If after this assessment the knee appears stable you can further assess the collateral ligaments by repeating this test with the knee flexed at 30°. At this position, the cruciate ligament is not taught so minor collateral ligament laxity can be more easily detected.

With healthy collateral ligaments, there should be no abduction or adduction possible.  If abduction/adduction is possible, it suggests laxity/rupture of the corresponding collateral ligament.

To complete the examination

Thank the patient

Wash your hands

Summarise your findings

Suggest further assessments and investigations

• Neurovascular examination of both lower limbs
• Examination of the joint above and below – ankle and hip
• Further imaging if indicated – X-ray / MRI

Further reading

1. Arthritis research UK provides some excellent free guides to musculoskeletal examination and history taking [LINK]

REVIEWED BY 

Mr Tejas Yarashi

Trauma & Orthopaedic Surgeon (ST7)