The McMurray’s Test is a common physical examination technique used in orthopedic and sports medicine settings to evaluate the integrity of the knee joint. This maneuver helps clinicians identify potential structural damage, specifically targeting the knee’s cushioning tissue. It serves as an initial screening tool to guide the diagnostic process before advanced imaging is considered.
The Purpose of the McMurray’s Test
The primary purpose of the McMurray’s Test is to screen for meniscal tears, which are injuries to the C-shaped cartilage within the knee joint. The medial and lateral menisci are wedges of fibrocartilage that function as shock absorbers and stabilize the knee between the femur (thigh bone) and the tibia (shin bone).
The test mechanically traps a torn portion of the cartilage between the bones as the knee moves. By applying rotational stress while the knee is flexed and extended, the clinician attempts to catch the damaged flap. If caught, this causes pain or a distinct sensation, suggesting a meniscal injury. This examination is used for patients presenting with joint line tenderness, mechanical locking, or pain following a rotational injury.
Executing the Examination Steps
The McMurray’s Test is performed with the patient lying flat on their back (supine). The examiner fully bends the patient’s knee and hip, holding one hand along the joint line and the other on the foot. This positioning allows the examiner to control the movement and apply specific forces.
The procedure involves two distinct maneuvers to test the medial and lateral menisci individually.
Testing the Medial Meniscus
To assess the medial meniscus, the examiner externally rotates the tibia while applying a valgus stress (pushing the knee outward). While maintaining this rotation and stress, the knee is slowly extended from its fully bent position.
Testing the Lateral Meniscus
To check the lateral meniscus, the examiner performs the opposite movement: internally rotating the tibia and applying a varus stress (pushing the knee inward). The knee is then slowly extended while maintaining the internal rotation.
Interpreting Positive and Negative Findings
The interpretation relies on specific reactions during the maneuver, which determine a “positive” finding. A positive test is indicated by a palpable or audible click, a popping sensation, or a sharp reproduction of pain along the joint line as the knee is extended. The mechanical click occurs when the torn meniscal flap is caught between the femoral and tibial condyles.
The specific rotation causing the reaction helps localize the injury. If the click or pain occurs during the external rotation and extension phase, it suggests a tear in the medial meniscus. Conversely, a positive result during the internal rotation and extension portion points toward a tear in the lateral meniscus.
A “negative” result means the maneuver did not elicit any pain, clicking, or popping sensation. However, a negative McMurray’s Test does not definitively rule out a meniscal tear. Due to the test’s variable accuracy, a negative finding means the clinician did not physically trap a torn piece of cartilage, though a tear may still exist.
The Test’s Role in Overall Diagnosis
The McMurray’s Test provides valuable information, but it is rarely used as a standalone diagnostic tool. Its accuracy varies widely; a positive result suggests a tear, but a negative result is poor at ruling one out. The test is considered one piece of a larger clinical picture.
A positive McMurray’s Test, combined with the patient’s history and clinical findings like joint line tenderness, prompts the next diagnostic step. This usually involves confirmatory imaging. Magnetic Resonance Imaging (MRI) is commonly used because it provides detailed pictures of soft tissues and is more accurate than the physical exam for assessing meniscal injuries.
The clinician may also perform other physical examinations, such as the Thessaly test or Apley’s test, to improve diagnostic confidence. The results guide the healthcare provider in determining the need for further workup, ranging from conservative therapy to surgical consultation.