KNEE EXAMINATION TECHNIQUES

sion. The postero-lateral capsule and arcu- ate complex also contribute to the range.

ANTERIOR CRUCIATE LIGAMENT The name relates to its distal attachment. The ACL descends anteriorly, inferiorly and medially from femur to tibia and prevents excess anterior tibial translation. It also contibutes to rotatory stability, in addi- tion to assisting in the normal gliding, rolling action of the knee a) Anterior drawer test – patient supine, hip at 45º, knee at 90º. The foot is fixed and after ensuring relaxation of the ham- strings the tibia is drawn forward. Excess motion may indicate injury to the ACL or posterior capsular structures (Fig.2)

It is necessary to check first that there is no posterior sag due to PCL injury, giving the impression of excess anterior tibial translation due to starting from a more posterior position.

Figure 4: Pivot shift test

c) Pivot shift test – this is a test of antero-lateral instability and is predomi- nantly a test for ACL deficiency. With the patient supine, the examiner holds the heel to place the leg in about 20º of hip flexion and slight abduction and internal- ly rotates the leg with the knee extended. In the ACL deficient knee the tibia will be displaced antero-laterally (Fig.4)

Figure 2: Anterior drawer test

b) Lachman’s test – the knee is placed in 20-30º of flexion and with the femur sta- bilised by the examiner’s hand (or knee as in Fig.3), the tibia is drawn forward. The amount of anterior tibial translation and end point are determined

Excessive translation (greater than a 3mm difference) compared with the other leg, along with a soft, mushy or spongy end feel (not the usual sharp one) equates to a positive test.

The other hand is placed by the fibula head and a valgus force applied as the knee is flexed to 30-40º.

As the knee flexes the ilio-tibial band ‘reduces’ the tibia back to its normal posi- tion and a sensation of giving way (+/- pain) is felt by the patient which may mimic their symptoms functionally.

POSTERIOR CRUCIATE LIGAMENT This extends infero-, postero-laterally from its femoral attachment and limits posterior tibial translation and hyperex- tension of the knee. It acts along with the ACL in guiding the ‘screwing home’ lock- ing mechanism of knee extension.

Posterior ‘sag’ sign – as indicated before a deficient PCL will cause the tibia to drop back in relation to the femur and this is inspected from the side. Patient supine, hip at 45º, knee at 90º.

Figure 3: Lachman’s test If positive then the patient is asked to a.

extend the knee and an active anterior drawer is seen as the tibia is drawn for- ward into its normal position.

b.

SPECIAL TESTS McMurray’s test – meniscal tests are not definitive and need careful interpretation. With the patient supine the examiner takes the heel in one hand whilst feeling over the joint line with the other. The knee is then fully flexed.

c.

For the medial meniscus the tibia is exter- nally rotated and the knee extended and vice-versa. A click may be felt over the joint line which may be painful. Apley’s test is no longer thought to be reliable.

Figure 5: McMurray’s test

Patellar apprehension – this test is per- formed to elicit previous dislocation of the patella. With the knee at about 30º flexion and the quadriceps relaxed, the examiner pushes the patella laterally.

The patient, sensing impending disloca- tion, looks apprehensive and contracts the quadriceps to prevent further dis- placement.

Functional tests – The examination find- ings to date may indicate the need for more functional tests. These could include squats, ‘duck walking’ and single leg hop tests (straight and cross-over).

Dr Nick Webborn is a full time sports physician with a particular interest in joint examination techniques, sport for the disabled, diabetes and exercise pre- scription. He has numerous articles and publications to his name and is medical advisor to both SportEX Medicine and the National Sports Medicine Institute. He is the medical officer to the British Paralympic swimming squad and has been a lecturer at the academic depart- ment of sports medicine of St Bartholomew’s and the Royal London School of Medicine and Dentistry.

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