What is Apley’s Test?
There are two types of Apley’s test, the Apley compression test and the Apley distraction test. The Apley distraction test is used for the evaluation of ligamentous injuries. Apley distraction test evaluates the integrity of the collateral ligaments (MCL & LCL) of the knee.
While the Apley compression test, also known as the Apley grind test, is used to evaluate meniscal injuries. Now, we will talk about both of these tests individually. So let’s first talk about the Apley compression test.
Apley Compression Test
The Apley compression test or Apley grind test is used to evaluate meniscal problems or injuries in the knee. This test was named after Alan Graham Apley (1914-1996), a British orthopedic surgeon who developed this method for assessing patients.
Meniscal injuries are quite common and can cause significant pain and morbidity. Children younger less than ten years are not likely to sustain meniscal injuries. Men are more likely to be afflicted than women. As men engage in more contact sports, so chance of rotational injuries are high.
Early diagnosis of meniscal injuries is essential to provide appropriate treatment. For proper diagnosis, doctor proper physical exam, provocative tests such as Apley grind test and Apley distraction test, and advanced imaging such as MRI (magnetic resonance imaging).
Now let’s understand the anatomy of the meniscus of the knee.
Anatomy of The Meniscus
The meniscus is C-shaped cartilage present in a pair in each knee joint. It is present between the two bones, mainly forming the knee joint, i.e. femur, and tibia. The meniscus is made up of both fibrous and cartilaginous components (fibrocartilaginous). They act as cushion-like padding between the distal femur and proximal tibia to make up the knee joint.
There are two types of meniscus in each knee joint
The lateral meniscus is more rounded than the Medial meniscus and covers more part of the tibial plateau surface.
The thick peripheral part of the meniscus surface is well supplied with blood and thus gets its nutrients normally by blood. But the inner part is avascular (lacks proper blood supply) and depends upon the synovial fluid for nutrition. Now movements is necessary for the absorption of the nutrients from the synovial fluid as well as nourishment of the middle third of the meniscus.
The cartilage structure of the meniscus acts as a shock absorber or cushion for the knee joint. The meniscus can be torn in several ways. There are several types of potential tears like a degenerative tear, flap tear, radial tear, horizontal tear, bucket handle tear, radial tear.
Functions of the meniscus
- It deepens the shallow articular surface of the tibia so that it can accommodate the large convex condyles of the femur.
- They increase the contact area between the two bones, thus decreasing the joint stress between the two.
- The meniscus acts as a shock absorber by dispersing the compression force from the femur on a wider (larger) area of the tibia.
- The menisci may also be involved in the lubrication or nourishment of the knee joints.
For More Details related to the meniscus functions, you can read – Biomechanics of knee joint: Tibiofemoral joint and meniscus.
Causes of Meniscal Tear
- These injuries are pretty common in athletes who are involved in contact sports like football or basketball. E.g., These injuries can be picked up when you receive a nasty tackle on the football pitch.
- They can also result from forceful rotation or twists of the knee. E.g., suddenly stopping or turning movement.
- Sometimes it can happen in people not related to sports. e.g., suddenly getting up from a squat, kneeling, or lifting heavy weight can cause a meniscal tear.
- In older individuals, the major cause of knee injury is the degenerative changes in the knee.
- Obesity is another risk factor.
Note – The medial meniscus is far more prone to injury when compared to the lateral meniscus. The reason behind that is that the medial meniscus is strongly attached to the medial collateral ligament. The lateral meniscus does not have any attachment to the lateral collateral ligament. Therefore it is more mobile and less susceptible to injury.
Apley compression (grind) test is used for the diagnosis of meniscal problems or injuries in the knee. In comparison, the Apley distraction test is used for the diagnosis of ligamentous problems. So both tests are performed in conjugation with one another.
The reason behind that is that the performing procedure of both tests is quite similar. As in the Apley grind test, the examiner gently compresses the tibia. While in the Apley distraction test, the examiner pulls up the tibia. Otherwise, the rest of the procedure remains the same.
Performing both tests allows the examiner to get a clearer vision in diagnosing either the meniscus or ligamentous tear as doctors cannot see the internal structures of the human body.
That’s why the doctors perform as many possible physical tests related to the injured area and also order radio imaging techniques like X-ray and MRI to make a more proper diagnosis.
Now Let’s understand the performing procedure of both the tests.
Apley Compression Test
- The patient lies in the prone(face downward) position on the examination table.
- Ask your patient to flex the tested leg to 90° at the knee joint while the other leg is fully extended.
- The examiner now puts his knee on the distal part of the patient’s back of the thigh gently.
- Now with one hand, the examiner applies a downward axial loading force on the sole of the foot to compress the patient’s knee joint. This compression force compresses the meniscus.
- While with the other hand, the examiner grasps the lower end of posterior aspect of the patient’s heel for stabilization.
- After that, along with the compression, the leg is rotated internally and externally, and the patient is asked for any pain response.
The Apley compression test is considered positive when the patient feels pain or restriction during compression and internal or external rotation. If the patient feels pain at the medial side of the knee, this indicates medial meniscus injury. If the patients feel pain at the lateral side of the knee, this indicates lateral meniscus injury.
Apley Distraction Test
The Apley distraction test is used for the diagnosis of collateral ligamentous injuries (MCL & LCL) of the knee. The Apley compression test is performed in conjugation with the Apley distraction test. The reason for this is explained above.
Let’s understand how it is performed.
The starting procedure of this test remains the same as of the Apley compression test.
- As in the same prone position, with the patient knee flexed to 90° and the examiner’s knee on the distal part of the patient’s back of the thigh.
- Instead of applying a downward axial loading force with one hand, the examiner will now pull up the patient’s affected leg. During this upward pulling, the examiner’s knee, which is resting on the distal part of the patient’s thigh, will prevent the patient’s femur from rising off the couch.
- This distraction force places a strain on the collateral ligaments (ACL & PCL) of the knee.
- While with the other hand, the examiner grasps the lower end of the posterior aspect of the patient’s heel for stabilization.
- After that, along with the distraction, the leg is rotated internally and externally, and the patient is asked for any pain response.
The Apley distraction test is considered positive when the patient feels pain or restriction during distraction and internal or external rotation. If the patient feels pain at the medial side of the knee, this indicates medial collateral ligament injury or damage. If the patients feel pain at the lateral side of the knee, this indicates lateral collateral ligament injury or damage.
Now let us discuss some questions.
Why compression force produces Meniscus pain, not distraction force?
This is because, on compression, the meniscus gets grinded between the two bones (femur & tibia). Thus rotation in that scenario produced much pain sensation. However, while during distraction, there is no pressure on the meniscus, thus painless rotation movement is present.
What happens when there is a ligamentous injury in one leg (Positive Apley distraction test)?
When Apley’s test is performed on both the legs of the patient, now during the distraction and rotation, we may observe a lot of mobility present in one of the legs. While on the other leg, during the distraction and rotation, the mobility is comparatively limited.
This shows that the leg which is allowing excessive rotation probably has a ligamentous injury. This can be inferred that the ligaments are responsible for restricting the excess rotation, which is missing here.
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