Meniscus tear diagnostics
Almost everyone has a friend or relative who has ever landed on the operating table due to a rupture of the meniscus of the knee joint. Such an injury is usually received either instantly: for example, if a leg bent at the knee is curled in some unnatural way. Or damage of this kind develops gradually, due to age-related degenerative processes and / or the constant repetitive stress of these structures.
Symptoms of a meniscus rupture include swelling of tissues on the injured side, pain in the knee joint (sometimes it spreads to other parts of the leg) and loss of the ability to fully extend the leg in the injured knee joint.
Of course, these symptoms do not always occur. Many clients who have received such an injury do not even suspect it, and their symptoms do not appear for several weeks. If the brain decides to warn him about the threat of possible tissue damage, the client may notice the appearance of painful clicks in the knee joint, a crunch and impaired mobility. In addition, it may seem to the client that the joint has become unstable, “as if the patella was about to fly out.” In particular, this sensation may worsen with increased load on the knee joint, for example, when climbing and descending stairs.
In this article I will describe the simplest diagnostic protocol that I myself regularly use.
Before we begin the discussion of meniscus injuries, I would like to turn to its anatomy – this will help us understand how such a strong cartilage lining can be damaged in general. The meniscus, consisting of dense and elastic cartilage, consists of two parts, which are often distinguished in the literature as separate menisci: the medial (internal) and lateral (external) menisci. They are located between the tibia and femur. The meniscus has a wedge-shaped shape – it thins toward the center of the knee and thickens outward (Fig. 1). From a functional point of view, these unusual C-shaped structures are extremely important for the distribution of load when walking, in a standing position, and so on. The knee joint itself consists of a rounded femur located on a relatively flat tibia – if there were no meniscus, the area of contact and the application of force between these two bones would be small enough, which would lead to instability of the entire structure. (Fig. 2). Normally, the medial and lateral menisci jointly absorb and increase the stability of the knee joint, which is actively involved in many movements, and also provide a smooth glide of the heads of two bones relative to each other.
The meniscus does not have the best blood supply, but in the outer third of the cartilage there are a lot of vessels. This indicates that small longitudinal gaps of a degenerative nature can repair on their own – good news for chiropractors trying to mobilize or stabilize the knee in the treatment of such an injury.
In my clinical practice, I am much more likely to encounter tears of the medial meniscus than the lateral one. Most often, the meniscus of the knee joint is injured along with the anterior cruciate ligament and the medial collateral ligament in those involved in football or skiing. Among English-speaking athletes, such an injury received the talking name “Unhappy triad” – “Unlucky Triad.”
DIAGNOSIS OF MENISK INJURIES
It is important to note that many orthopedic tests should be carried out in a complex – individually they are not so reliable. When combining the three tests for damage to the meniscus of the knee joint, which will be discussed later, the degree of accuracy (the ability to determine which tissues are damaged) and specificity (the ability to differentiate a particular type of injury from similar ones) are significantly increased – especially if before performing these tests you carefully collected history.
McMurray Modified Test
The McMurray Modified Test is a pain provocation test that helps determine which meniscus is damaged – medial or lateral. This test is shown in Fig. 3: the client’s leg is bent at an angle of 90 degrees in the thigh and knee, the massage therapist’s left thumb squeezes the lateral meniscus, and the index finger squeezes the medial meniscus at the femoral-tibial joint line. If, as the massage therapist slowly moves the tibia from the abduction and rotation outward to the adduction and rotation inward position (valgus of the knee joint), the client feels discomfort or silk along the lateral meniscus border, the McMurray test on this side (lateral meniscus) can considered positive. In turn, if the pain occurs when the knee is moved to the abduction and rotation outward position (varus of the knee joint), and the client notices discomfort or clicks from the side, the medial meniscus is likely to be damaged.