Finding the Cause of Knee Pain: Is MRI the Solution?

Knee injuries can be as frustrating as they are debilitating. The knee is one of the most complex joints in the body. It has many important structures that need to work in unison for the joint to function correctly. Damage to one of these individual structures can result in pain. If left untreated can lead to more serious knee complications in the future.

Research has shown 23% of participants have experienced a form of knee injury, 51% of those injuries required hospitalization. The most prevalent are ligament injuries, accounting for 40%, while 25% are miscellaneous injuries, such as contusions and strains.

Furthermore, 24% are patella related injuries, and 11% are meniscus injuries. With many possible injuries, each involving different aspects of the knee joint, it’s virtually impossible to determine the cause of knee pain through physical examination alone. An MRI scan can provide a detailed image of the knee, showing any damage, and allows physicians to make an accurate diagnosis.

Early intervention is essential to a quick and full knee recovery. An MRI scan of the knee is a painless diagnostic procedure that can help produce an accurate diagnosis, to get you back on your feet. Continue as we discuss what the most common knee injuries are, and what you can expect from a knee MRI scan.

What is the Anatomy of the Knee Joint?

The knee is a type of synovial hinge joint, consisting of:

1. Bones
   1. Patella (Kneecap)
   2. Femur
   3. Tibia
2. Ligaments
   1. Anterior Cruciate Ligament (ACL)
   2. Lateral Cruciate Ligament (LCL)
   3. Medial Cruciate Ligament (MCL)
   4. Posterior Cruciate Ligament (PCL)

Tissues

1. 1. Meniscus
   2. Joint Capsule
   3. Synovial Membrane
   4. Hyaline Cartilage

The soft, fibrous tissues ensure the bones are protected from friction and shock damage, while also keeping the joint lubricated. The ligaments hold the knee joint together, keeping the hinge joint moving in the correct direction. This integrated network of structures work to move your knee, support the weight of your upper body and are necessary for you to perform everyday functions like walking, sitting and standing. The knee can only function correctly when all of these structures work in unison, when one is damaged it puts further strain on the rest of the joint components.

Why Should I Get an MRI Knee Scan Procedure?

Knee pain means there has been damage to a component of the knee joint. Sometimes it can be a simple strain and can be managed with rest and physiotherapy. However, other times it can be a serious injury to an important structure or the sign of a degenerative disorder.

The most common injuries include:

• Ligament Tears
• Meniscus Tears
• Patellar Dislocation
• Contusion
• Fracture

A Magnetic Resonance Imaging (MRI) scan uses a powerful magnetic field to capture multiple images of the knee joint. These detailed pictures showcase the soft tissues, ligaments, and muscles surrounding the joint. Since the knee is a complex network of structures, the best way for a physician to provide a diagnosis, is through examining an MRI knee scan. An early diagnosis leads to early intervention and is imperative to making a full recovery.

If you are experiencing any of the following symptoms,

• Knee joint pain that increases with exercise
• Limited range of motion
• Sudden weakness in your knee
• Direct injury to the knee joint
• Swelling or fluid collection around the knee

It could be of value to have an MRI knee scan to help identify the root of the problem.

What Does an MRI of the Knee Show?

An MRI knee scan produces detailed images of the knee joint, including,

• Tibial and Femoral Condyles (rounded end of the bone)
• Patella
• Ligaments
• Meniscus
• Joint Capsule

Unlike an X-ray, an MRI scan procedure can show the extent of damage to the fibrous tissue structures in the knee. This allows doctors the opportunity to diagnose,

• Fractures
• Degenerative diseases (such as osteoarthritis)
• A build-up of fluid in the Knee
• Infections
• Tumours
• Decreased range of motion
• Joint weakness
• Damage to ligaments, meniscus, or soft tissues
• Possible ligament or tissue tears

Early intervention is important for the recovery of knee injuries, an MRI scan increases the ability to accurately diagnose the cause of your knee pain, and begin the rehabilitation process.

How Do You Read a Knee MRI Scan?

An MRI scan takes images at three different angles:

• Axial - From the top looking down
• Sagittal - From the side
• Coronal - From the front

A great way to understand how an MRI scan works is to imagine the knee as a tomato. Slices of the tomato are being cut from one side to the other, each one of those slices represents a single MRI image. Each image is a cross-section of the knee joint, as it moves from one side to the other, along one of the three angles.

A radiologist is a doctor who specializes in reading and interpreting MRI scans. They will move through the images, across one angle at a time to identify the key knee structures, looking for changes and inconsistencies in colour or shape. They will be able to identify issues such as fluid build-up, deterioration of important knee structures, or ligament tears. If an issue is identified, they can move through the set of images across the other two angles to assess the severity of the damage.

The radiologist will sign off on your scan and send it to your physician, who will discuss the results with you and advise a treatment plan if required. In some instances, there will need to be a follow-up MRI scan to evaluate the effects of the treatment, or if there is no decrease in pain.

How Long Should an MRI Knee Scan Take?

An MRI scan of your knee should take on average 10–30 minutes. You will be instructed to wear a hospital gown or loose-fitting clothing without metal clasps or zippers. Certain types of metal can interfere with the MRI machine, causing blurred images. If this occurs the scan will need to be repeated.

It is important to stay extremely still during this procedure. Sudden movements during the scan can also produce blurred images. If this happens, the scan will need to be repeated causing a longer MRI procedure.

How Much Does a Knee MRI cost?

Prices for knee MRI scans can vary based on your location, the hospital you choose, and whether or not you need a separate appointment with a consultant to get a referral.

We're the UK's largest imaging network with over 200 scanning centres to choose from, with complete pricing transparency that includes a pre-scan consultation, your referral, your scan, copies of your report and images, and a post-scan follow-up call. Scan.com makes it easier to compare prices across all of the options near you with no hidden costs, with knee MRI scan costs starting from just £295.

The benefit of choosing a private MRI knee scan is reduced wait times. Currently, to receive a non-urgent MRI through the NHS, the wait time can be up to 18 weeks or more. Our private MRI clinics offer a quick alternative, most appointments can be made within two weeks. Knee injuries can often begin as a small issue, growing more severe and painful over time. It’s important to identify the issue quickly to intervene with the appropriate medical treatment.

What do I Need to Do to Prepare for an MRI Knee Scan?

Before your scan, it is common for your technician to go over your medical history, including any allergies. Since some procedures use an iodine contrast material, your technician needs to know if you have any known allergies to this material. At this time, it is important to inform the technician of any implanted medical device, such as a pacemaker or defibrillator. MRI technology advancements have made it safe for those with implanted medical devices to undergo an MRI scan. However, the powerful magnetic field can potentially cause changes in the settings of these devices. It’s advised to also inform your radiographer if you are pregnant. There is currently no link between MRI scans and adverse birth defects, but it is important to disclose your full medical history.

Furthermore, before your scan, you will need to change into a hospital gown. Some clinics will allow you to wear your clothing, so long as they are loose-fitting and do not contain any metal fasteners. Each clinic has its guidelines about eating and drinking before a procedure. Generally, it is not necessary to fast before an MRI knee scan unless otherwise specified.

The Bottom Line

Knee injuries can be debilitating, but early intervention can increase the potential to make a full recovery. Taking advantage of an MRI knee scan can help speed up your diagnosis and get you on the road to rehabilitation.

If you are thinking about an MRI knee scan and would still like additional information, visit our Frequently Ask Questions page. Or contact us, our team will be happy to assist you with any questions you may have.

References

1. https://bjsm.bmj.com/content/34/3/227.2
2. https://www.innerbody.com/image/skel16.html
3. https://pubmed.ncbi.nlm.nih.gov/22506941/
4. https://josr-online.biomedcentral.com/articles/10.1186/s13018-020-01638-1
5. https://www.radiologyinfo.org/en/info/kneemr
6. https://regenexx.com/blog/read-knee-mri/#gref
7. https://medlineplus.gov/ency/article/007361.htm