The patient lies in the supine position, and the clinician, standing on the same side as the involved knee, maximally flexes the hip and knee. This is accomplished by grasping the patient’s foot in such a way that the thumb is lateral, the index and middle fingers are medial, and the ring and little fingers hold the medial edge of the foot. The thumb of one hand is placed against the lateral aspect of the patient’s knee.
To test the medial meniscus: the clinician rotates the tibia into external rotation, then slowly extends the knee.
To test the lateral meniscus: the clinician flexes the knee again but now internally rotates the patient’s tibia and then slowly extends the knee.
What is a positive McMurray Test?
McMurray test is Positive when there is a click (or catch) and pain in the extension of the knee.
Pain while extending the knee with the lower leg externally rotated and abducted suggests a medial meniscus lesion; while pain in internal rotation suggests an injury to the lateral meniscus.
A snapping sound in extreme flexion occurs when a projecting meniscal flap becomes impinged on the posterior horn.
Snapping in 90° of flexion suggests an injury in the middle section of the meniscus.
The snapping symptoms can be increased by moving the entire lower leg in a circle (modified McMurray test).
Sensitivity & Specificity
A Meta-Analysis study by Ockert 1 to assess the value of the clinical examination in suspected meniscal injuries, the Sensitivity & Specificity of McMurray Test was:
Sensitivity: 51 %
Specificity: 78 %
Another Systematic review and meta-analysis by Eric J Hegedus 2 found that the pooled sensitivity and specificity were 70% and 71% for McMurray test.
Numerous variations exist for the McMurray test, including the addition of varus / valgus stresses. An examination of the variation seemed to indicate that the McMurray test has some value as a specific test where a positive test would rule in the disease.
Continuing the extension as far as the neutral (0°) position corresponds to the Bragard test.
This test, when performed by slowly extending the knee with the lower leg in external rotation to test the medial meniscus, is also described as the Fouche sign.
The McMurray test is positive in 30% of all children with normal knees.
Approximately 1% of the normal population should test positive.
In plan view the medial and lateral menisci are C-shaped; they are triangular in cross-section, and formed from dense avascular fibrous tissue.
Their extremities (horns) are attached to the upper surface of the tibia on which they lie; the posterior horn of the lateral meniscus has an additional attachment to the femur, whereas both anterior horns are loosely connected.
The concave margin of each meniscus is unattached; the convex margin of the lateral meniscus is anchored to the tibia by coronary ligaments, whereas the corresponding part of the medial meniscus is attached to the joint capsule) and thereby loosely united to both femur and tibia.
During extension of the knee the menisci slide forwards on the tibial plateau and become progressively more compressed, adapting in shape to the altering contours of the particular portions of the femur and tibia between which they come to lie.
Only the peripheral edges of the menisci have an appreciable blood supply, so that meniscal tears that involve the more central portions have a poor potential for healing.
The lateral meniscus of the knee is more circular in form, covering up to two thirds of the articular surface of the underlying tibial plateau.
The tendon of the popliteus muscle separates the posterolateral periphery of the lateral meniscus from the joint capsule and the fibular collateral ligament.
It’s more mobile than the medial meniscus.
The average width is 10 to 12 mm, and the average thickness is 4 to 5 mm.
It’s less likely to be injured because it is firmly attached to the popliteus muscle and to the ligament of Wrisberg or of Humphry, which make it follows the lateral femoral condyle during rotation.
The semilunar or U-shaped medial meniscus, with the wider separation of its anterior and posterior horns, is larger and thicker than its lateral counterpart and sits in the concave medial tibial plateau.
The medial meniscus is wider posteriorly than anteriorly.
It is attached to the anterior and posterior tibial plateau by coronary ligaments. These ligaments connect the outer meniscal borders with the tibial edge and restrict movement of the meniscus.
The medial meniscus also has an attachment to the deeper portion of the MCL and the knee joint capsule.
The horns of the medial meniscus are further apart than those of the lateral, which makes the former nearly semilunar and the latter almost circular.
The posterior horn of the medial meniscus receives a piece of the semimembranosus tendon.
The transverse genicular ligament serves as a link between the lateral and medial menisci
Being anchored to the capsule tighter, the medial meniscus has less mobility than the lateral one, provoking a greater risk for ruptures.
meniscal tears can occur as acute injuries with a history of an adequate trauma (most commonly twisting), or they can be presented as a degenerative rupture usually without any memorable violent event.
Intermittent pain at the joint line and swelling are the most frequent symptoms; depending on the size and the pattern of the tear where the knee can become “locked” in a bent position
Ockert B, Haasters F, Polzer H, Grote S, Kessler MA, Mutschler W, Kanz KG. Der verletzte Meniskus: Wie sicher ist die klinische Untersuchung? Eine Metaanalyse [Value of the clinical examination in suspected meniscal injuries. A meta-analysis]. Unfallchirurg. 2010 Apr;113(4):293-9. German. doi: 10.1007/s00113-009-1702-2. PMID: 19960176.
Hegedus EJ, Cook C, Hasselblad V, Goode A, McCrory DC. Physical examination tests for assessing a torn meniscus in the knee: a systematic review with meta-analysis. J Orthop Sports Phys Ther. 2007 Sep;37(9):541-50. doi: 10.2519/jospt.2007.2560. PMID: 17939613.