Knee Range of Motion Test

Knee problems that affect the knee's motion

Several knee problems can significantly impact the knee's motion, affecting daily activities and overall mobility. One common issue is injury to the anterior cruciate ligament (ACL), which is crucial for stabilizing the knee joint. An ACL injury often results in knee pain, swelling, and difficulty achieving full knee extension, limiting both internal and external rotation. Another prevalent issue is osteoarthritis, a degenerative joint disease that leads to the deterioration of cartilage, causing stiffness and reduced knee flexion. This condition can make it challenging to measure knee extension effectively, as patients may struggle with terminal knee extension or flexion.

When to perform a knee assessment

Medical professionals should perform a knee assessment when a patient presents with symptoms such as knee pain, swelling, or stiffness that affects mobility. Assessments are crucial following a knee injury, particularly if there is a history of trauma or instability, to evaluate potential ligament damage or meniscus tears. Additionally, knee assessments should be conducted during pre-operative evaluations for knee surgery interventions or post-operative follow-ups to monitor recovery progress.

What is the Knee Range of Motion Test?

The Knee Range of Motion Test is a clinical assessment used to evaluate the flexibility and mobility of the knee joint. This test measures key movements, including measuring knee flexion, knee extension, and both internal and external rotation, to determine the functional capacity of the knee. Measuring knee range should be accurate as it is essential for diagnosing conditions, monitoring progress, and planning effective treatment interventions for patients with knee problems.

There are two types of Knee Range of Motion Test: active and passive. In the active test, the patient is asked to move their knee on their own without any assistance from a medical professional. In contrast, in the passive test, a medical professional moves the patient's knee manually to assess its range of motion.

Both tests are vital in different scenarios; for example, an active range of motion test is suitable for evaluating functional capacity and identifying muscle imbalances or weaknesses, while a passive range of motion test can help determine potential joint limitations or stiffness.

How are these tests conducted?

Here's how to perform the active and passive Knee Range of Motion Test (Physiotutors, n.d.-a; Physiotutors, n.d.-b):

Active Knee Range of Motion Test

1. The examiner instructs the patient to lie supine and bring their heel as close as possible to their buttocks, noting the degree of flexion.
2. The patient contracts their quadriceps or pushes their knee into the examination table, aiming for the heel to lift off the table, indicating full knee extension.
3. As the patient performs flexion and extension, the examiner observes the patella to ensure it tracks smoothly along the femoral trochlea. The patella should move upward and laterally during knee extension, and downward and medially during flexion.
4. For the ankle assessment, the patient sits on the table with their legs hanging freely.
5. The patient is instructed to palpate above the ankle joint to distinguish between ankle inversion/eversion and actual tibial rotation.
6. The examiner holds the tibia and instructs the patient to rotate their ankle outward, aiming for 30 degrees of external rotation.
7. Finally, the examiner asks for inward rotation to reach 20 to 30 degrees.

Passive Knee Range of Motion Test

This test assesses the flexion, extension, internal and external rotation, and patellar mobility:

• Flexion assessment 135° to 145°: To conduct a flexion assessment at 130°, the examiner positions the patient supine and flexes their leg to 90° at the hip while stabilizing the distal femur with one hand. With the other hand, the examiner grasps the distal tibia and performs maximal flexion, then assesses the end feel.
• Extension assessment -1° to -5°: The extension assessment requires the patient to be positioned supine with the leg flat on the bench. The examiner stabilizes the distal femur with one hand while grasping the distal tibia medially with the other hand to perform passive extension. It is important for the examiner to grip the tibia medially to facilitate the “screw-home” mechanism during terminal knee extension.
• Internal and external rotation assessment (20-30° / 30-40°): The examiner positions the patient in a supine posture. They flex the patient's hip and knee to a 90° angle, securing this position with one hand. With the other hand, the examiner grasps the foot from the plantar side and elevates the talocrural joint into maximal dorsiflexion for stabilization. The examiner then rotates the tibia internally, followed by external rotation.
• Patella mobility assessment: The examiner positions the patient in a supine lying position with the leg fully extended. To assess the medial glide, the examiner gently presses on the patella using both thumbs. For the lateral glide, the examiner applies pressure laterally with their index fingers. For the distal glide, the examiner uses their index finger and thumb, or the pisiform bone, to apply pressure. For the proximal glide, the examiner pushes the patella with their index finger and thumb.

How are the results interpreted?

During the active Knee Range of Motion Test, healthcare professionals should record their observations of the four active movements assessed--flexion, extension, internal rotation and external rotation.

For the passive Knee Range of Motion Test, examiners should also document their measured range of motion, type of end feel, and end feel description for every assessment conducted.

While each test doesn't have definite positive and negative results, the examiner can compare the patient's results with established norms to determine deviations or abnormalities. For example, a loss of 10-30° in active extension could potentially indicate quadriceps muscle weakness.

Furthermore, the combined results from both tests and their interpretation can assist in diagnosing potential conditions affecting the knee joint, such as ligament injuries or osteoarthritis.

How to use our Knee Range of Motion Test template

Using the Knee Range of Motion Test template is a straightforward process designed to facilitate accurate assessments of knee functionality. This template serves as a valuable tool for healthcare practitioners to efficiently evaluate and document their patients' knee range of motion, ensuring effective diagnosis and treatment planning.

Step 1: Access and download the template

To begin, access the Knee Range of Motion Test template from Carepatron's resource library. Download the PDF test template once located.

Step 2: Review the test template

Once downloaded, take a moment to thoroughly review the test template. Familiarize yourself with the structure. Understanding the template's layout will enhance your efficiency during the assessment, ensuring you capture all necessary information accurately.

Step 3: Conduct the tests

Perform both the active and passive Knee Range of Motion Tests with your patient by adhering to the steps outlined in the template. Ensure that your patient comprehends the necessary movements and guide them through each action.

Step 4: Provide proper diagnosis and next steps for the patient

Based on your findings, deliver a suitable diagnosis and discuss potential treatment options with your patient. This may involve referrals for further imaging, physical therapy, or a customized rehabilitation program aimed at improving knee function and alleviating pain.

Benefits of conducting this test

Conducting the Knee Range of Motion Test offers several advantages for both healthcare practitioners and patients. Here are three key benefits:

Early detection of knee issues

One of the primary benefits of this test is its ability to facilitate the early detection of knee problems. By assessing the range of motion, practitioners can identify limitations or abnormalities that may indicate underlying conditions, such as ligament injuries or arthritis.

Informed treatment planning

By understanding a patient's specific range of motion deficits, healthcare practitioners can tailor rehabilitation programs to target areas of concern. This individualized approach enhances the effectiveness of therapeutic interventions and promotes faster recovery.

Monitoring progress over time

Regularly conducting the Knee Range of Motion Test allows practitioners to monitor a patient’s progress over time. Healthcare providers can evaluate the effectiveness of treatment strategies, make necessary adjustments, and motivate patients by demonstrating improvements in their knee function.

References

Physiotutors. (n.d.-a). Knee active range of motion | basic AROM assessment. https://www.physiotutors.com/wiki/knee-active-range-of-motion/

Physiotutors. (n.d.-b). Knee passive range of motion | basic AROM assessment. https://www.physiotutors.com/wiki/knee-passive-range-of-motion/