The McMurray Test is a specific maneuver healthcare providers use during a physical examination to evaluate patients presenting with knee pain. This simple, in-office screening tool assesses the integrity of internal structures within the knee joint, primarily determining if the cushioning cartilage may be damaged. A positive result suggests a structural issue that warrants further investigation. This initial finding helps the clinician narrow down potential causes of discomfort and guides the subsequent diagnostic process.
Understanding the Physical Examination
The McMurray Test is performed with the patient lying on their back while the clinician manipulates the leg. The provider first bends the knee to its maximum flexed position, compressing the menisci. To test the inner (medial) meniscus, the examiner rotates the foot outward (external rotation) and applies slight outward force (valgus stress) while slowly straightening the knee. To assess the outer (lateral) meniscus, the foot is rotated inward (internal rotation) with slight inward force (varus stress) as the knee is extended.
A positive result is characterized by the reproduction of the patient’s pain, or by the examiner feeling or hearing a distinct click, clunk, or pop within the joint. This indicates that a piece of torn or unstable tissue is being momentarily trapped and then released between the femur and the tibia. These mechanical symptoms are physical evidence that a fragment of cartilage is catching on the joint surfaces. It is important to understand that this is a clinical finding, not a final diagnosis, and its diagnostic accuracy can vary widely depending on the patient’s condition and the examiner’s skill.
Identifying the Underlying Injury
A positive McMurray Test strongly suggests a tear in the meniscus, the C-shaped fibrocartilage that acts as a shock absorber between the femur and tibia. Each knee has two menisci, the medial and the lateral, which stabilize the joint and distribute load across the knee surfaces. When a tear occurs, a mobile fragment of the cartilage can become displaced, causing the mechanical symptoms detected during the physical examination. Tears often result from a twisting injury while the foot is planted, or from gradual degeneration over time.
The specific pattern of the tear significantly influences the likelihood and type of mechanical symptom a patient experiences. Tears that create a loose, unstable fragment are the most likely to produce the clicking or locking sensation associated with a positive test. The location of the pain during the test—inner or outer knee—helps the provider differentiate between a medial or lateral meniscal tear.
Types of Meniscal Tears
Tears that create loose, unstable fragments are most likely to produce the clicking or locking sensation. For instance, a flap tear or a large, displaced bucket-handle tear can physically block the knee’s normal range of motion. A bucket-handle tear is an extended vertical tear where the detached inner portion flips into the center of the joint, often leading to acute knee locking.
Other tear patterns, such as a radial tear that cuts across the cartilage, or a horizontal tear that splits the meniscus into upper and lower layers, may produce less distinct mechanical symptoms. Current research suggests that traditional mechanical symptoms may correlate more strongly with underlying cartilage damage than with the specific meniscal tear pattern, especially in older patients.
Next Steps for Diagnosis and Recovery
Following a positive McMurray Test, the next step is typically to seek definitive confirmation of the meniscal injury and rule out other potential causes of knee pain. Initial imaging often includes standard X-rays, which assess for bone fractures or signs of advanced arthritis that could mimic meniscal symptoms. Although X-rays cannot visualize the soft cartilage, they provide a valuable structural overview of the joint.
Confirmation of a meniscal tear, including assessment of its size, location, and severity, requires Magnetic Resonance Imaging (MRI). MRI is the preferred non-invasive method for imaging soft tissues, offering detailed cross-sectional views of the knee’s internal structures. This imaging helps the healthcare team determine the most appropriate treatment plan, which depends on the tear’s characteristics and the patient’s activity level.
Initial management for a suspected meniscal tear, even before final imaging, often involves conservative measures to reduce pain and swelling. The RICE protocol—Rest, Ice, Compression, and Elevation—is a standard recommendation to manage acute symptoms. Treatment pathways range from non-surgical options, including physical therapy to strengthen surrounding muscles, to surgical intervention. Surgical choices include arthroscopic repair (stitching the tear) or a partial meniscectomy (trimming the unstable cartilage), depending on the tear type and its blood supply.