Knowledge · Clinical Examination

Knee Examination: Effusion, Ligaments, Menisci and the Ottawa Knee Rule

By Dr Richard Miller, MBChB FRCS with the MRCS Part B Questions Team · Reviewed 15 September 2026

In brief

Examine the knee with look, feel, move and stability testing; NICE CKS gives a normal range of zero to 135 degrees, supports Lachman and drawer testing, and states that meniscal tests such as McMurray's have particularly poor diagnostic accuracy.

Examine the knee by looking at both legs standing and lying, feeling for warmth, effusion and joint line tenderness, moving through flexion and extension, then testing the ligaments. NICE Clinical Knowledge Summaries give a normal range of zero degrees of extension to 135 degrees of flexion and warn that meniscal provocation tests have poor diagnostic accuracy.

Key takeaways

NICE CKS gives normal knee movement as zero degrees of extension to 135 degrees of flexion.
Lachman's test is performed at 20 to 30 degrees of flexion and is positive with anterior movement and a soft end point.
NICE CKS states that McMurray, Thessaly and Apley tests are not recommended because their diagnostic accuracy is particularly poor in non-specialist settings.
The Ottawa knee rule applies to people over 2 years of age and includes age 55 or over, fibular head tenderness, isolated patellar tenderness, inability to flex to 90 degrees, and inability to weight bear for four steps.
After trauma, NICE CKS asks for an active straight leg raise and a check for a palpable gap in the quadriceps or patellar tendon.

What is the examiner marking at the knee station?

The Intercollegiate blueprint marks a physical examination station out of 20 across four domains: clinical and technical skill carries 8 marks, and clinical knowledge and its application, communication and professionalism carry 4 marks each. The station also gets a separate global rating of pass, borderline or fail.

More than half the marks therefore sit outside your knowledge of the condition, so a silent but technically correct examination scores poorly. You are signalled at six minutes of the nine to present your findings, so the sequence has to finish inside six.

The examiner is marking a complete sequence, gentle technique and honest interpretation of unreliable tests. Knowing which tests are poor is itself a mark.

Compare both knees throughout and expose from mid-thigh to the ankle so the whole limb is visible.

What am I looking for on inspection of the knee?

Look with the patient standing, then walking, then lying.

Scars, sinuses, erythema and swelling
Quadriceps wasting, measured if you have time
Varus or valgus alignment, best seen standing
Effusion, and the resting position of the patella

**Valgus alignment** is a knee that deviates towards the midline, while varus alignment is bow-legged; both change where the load and the pain sit.

How do you feel for an effusion?

Compare temperature with the back of your hand, then test for fluid. NICE CKS describes the patellar tap, in which you squeeze the suprapatellar pouch and then push the patella to bounce it against the femur.

For a smaller effusion, sweep fluid from the medial gutter into the lateral compartment, then press laterally and watch the medial gutter refill.

Palpate the joint line with the knee flexed to 90 degrees, then the collateral ligaments, the patellar tendon and the popliteal fossa.

Which movements should you test, and what is normal?

Test active then passive flexion and extension, feeling for crepitus, with a normal range of zero to 135 degrees per NICE CKS.

Lift the leg by the ankle to check for fixed flexion, and after trauma ask for an active straight leg raise, which NICE CKS uses to test the extensor mechanism.

Which special tests confirm a cruciate ligament injury?

Lachman's test is the primary cruciate test. NICE CKS describes it with the patient supine, the leg slightly externally rotated and the knee at 20 to 30 degrees, stabilising the thigh with one hand and pulling the upper tibia forward with the other; it is positive with anterior motion and a soft end point.

Anterior drawer test at about 90 degrees of flexion, with the foot stabilised
Posterior drawer test from the same position, pushing the tibia backwards
Posterior sag, viewed from the side with both knees flexed to 90 degrees
Pivot shift, which is uncomfortable and is usually offered rather than performed

How do you test the collateral ligaments and menisci?

Apply valgus and varus stress with the knee held at about 30 degrees of flexion, with your fingers over the joint line to feel it open.

Be honest about menisci. NICE CKS states that specific meniscal tests, naming McMurray, Thessaly and Apley, are not recommended because their diagnostic accuracy is particularly poor, and that all provocative knee tests have limited accuracy.

What are the most common mistakes at the knee station?

Performing McMurray's test with force and presenting it as confirmation of a tear
Testing the collaterals in full extension rather than at about 30 degrees
Missing an extensor mechanism rupture by not asking for a straight leg raise
Forgetting the Ottawa knee rule when the history is traumatic
Omitting the neurovascular check, which NICE CKS includes along with considering compartment syndrome

How should you finish the knee examination?

Examine the hip, ankle and spine for referred pain, assess gait and weight bearing, then state your imaging plan.

NICE NG38 recommends using the Ottawa knee rules in people over 2 years with suspected knee fractures, and NICE CKS lists the criteria as inability to weight bear for four steps immediately and in the consultation, inability to flex to 90 degrees, fibular head tenderness, isolated patellar tenderness, or age 55 or over.

The MRCS Part B Questions bank has a knee examination station at /Sample-Questions.

Key evidence

Knee pain assessment: examination — NICE Clinical Knowledge Summaries (2025)
Knee pain assessment: excluding fracture, the Ottawa knee rule — NICE Clinical Knowledge Summaries (2025)
Fractures (non-complex): assessment and management (NG38), recommendation 1.2.1 — National Institute for Health and Care Excellence (2016)

FAQ

Is Lachman's test better than the anterior drawer test?

NICE CKS lists both for anterior cruciate ligament injury, with Lachman performed at 20 to 30 degrees and the drawer at about 90 degrees. Lachman is easier in an acutely painful knee because it needs less flexion. Interpret either alongside the history and the rest of the examination.

Why does NICE advise against McMurray's test?

NICE CKS states that specific tests for meniscal injuries, including McMurray, Thessaly and Apley, are not recommended because they have particularly poor diagnostic accuracy, especially in non-specialist settings. Joint line tenderness and a mechanical history carry more weight. Saying this in the station shows judgement.

How do I detect a small knee effusion?

Use the sweep or bulge test: empty the medial gutter upwards, then apply pressure laterally and watch the medial side refill. The patellar tap, described by NICE CKS, detects larger effusions by bouncing the patella on the femur after squeezing the suprapatellar pouch. Compare with the other knee.

What is the Ottawa knee rule?

It decides whether a radiograph is needed after knee injury in people over 2 years of age. NICE CKS lists inability to weight bear for four steps immediately and during the consultation, inability to flex the knee to 90 degrees, tenderness of the fibular head, isolated patellar tenderness, and age 55 or over. NICE NG38 recommends its use.

What should I check after a patellar dislocation?

NICE CKS asks you to check the position of the patella, which is usually lateral in dislocation, proximal in patellar tendon rupture and distal in quadriceps tendon rupture. Test the active straight leg raise and feel for a gap in the tendon. Assess neurovascular status before and after any reduction.

Which joints should I examine alongside the knee?

NICE CKS asks you to examine the hips, ankles and spine for other joint pathology causing referred pain to the knee, particularly in children. A slipped upper femoral epiphysis presenting as knee pain is the classic trap. Always assess gait and weight-bearing ability too.

The MRCS Part B Questions Team

Written and maintained by doctors who have sat and scored well at this interview, and reviewed against the current published guideline in each case. Guidance changes — check the source before you rely on a threshold.

Last reviewed 15 September 2026

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