Internal derangement of knee is the name given to a few conditions that can affect the knee area. It encompasses joint disorders, loose bodies in the knee joint, damaged ligaments and a torn meniscus. These conditions can either occur alone or in combination with each other. It does, however, not include conditions like osteoarthritis of the knee. It is usually caused by trauma to the knee by sports like football, basketball and skiing. It can also be caused by chronic overuse.

What Is Internal Derangement of Knee?

This condition can involve a ligament or tear in the meniscus of the knee joint.

A ligament is tough connective tissue that connects bones together. Two important ligaments in the knee joint are the ACL (anterior cruciate ligament) and the PCL (posterior cruciate ligament). They attach all the bones of the knee joint together: the femur, patella and the tibia.

The meniscus, which is also a soft tissue, is a rubbery disc that is C-shaped and its purpose in the knee joint is to balance the total body weight equally on the knee joint.

When this type of injury occurs, the person is usually aware of a tearing or snapping sensation. This can be followed by swelling and instability in the knee. This is usually in response to a major trauma to the knee joint.

Causes of Internal Derangement of Knee

The condition can occur through a range of activities: sports, work-related activities and even car accidents. Here are the causes:

• A sudden shift of body weight from one knee to the next
• A sudden stop while running
• Direct trauma to the knee i.e. getting hit on the knee joint
• Landing heavily on a flexed knee joint
• A medial collateral ligament (MCL) injury can occur in sports like football or rugby where the body above the knee joint twists but the leg below the knee joint stays in a fixed position.
• ACL injuries can occur, for example, in a gymnast who misses a landing on the feet and ends up hyperextending the knee joint on impact with the landing surface.
• People older than 60 can be more prone to knee joint disorders than younger people.

Diagnosis of Internal Derangement of Knee

Your medical practitioner will perform some physical exams to check for:

• Any cuts or bruises on the knee
• Swelling of the knee
• Dislocated patella (triangular bone in front of the knee)
• Moving the joint will reveal any ligament instability or meniscal tears.

Your doctor may order the following tests to further diagnose your internal derangement of the knee:

• X-ray
• CT scan
• Arthroscopy-an invasive surgical procedure where a tiny camera is inserted into the knee joint for viewing.
• MRI-used most commonly because ligaments, menisci and tendons can be viewed easily.

Treatments for Internal Derangement of Knee

Any treatment necessary will depend on the type and severity of the injury. Take the advice of your medical practitioner before you try any home remedies to prevent any potential long-term complications. The body is capable of healing a mild injury by itself. You can speed up your healing process by:

• Keeping the weight off the knee joint. Use crutches to improve your mobility without using the affected knee joint. Rest the knee as much as possible.
• Apply cold compresses to the painful knee joint regularly to ease the pain and swelling. Ice can be applied for a few days, every few hours for 20 minutes at a time.
• Compression bandages will control the swelling. There are many products commercially available that will work well.
• When resting your knee, keep the affected knee joint elevated on a pillow. This will also help reduce the swelling.
• There are special knee braces available to stabilize and protect the injured knee.
• Over-the-counter non-steroidal anti-inflammatories will reduce your symptoms of inflammation like the pain and swelling. Remember to use these medicines sparingly as they have side-effects as well.
• Mild and gentle stretching can help your internal derangement of the knee to strengthen and heal faster. You can watch the video below to learn some exercises that can relieve your knee pain and help you gain strength:
• Some people benefit from physical therapy with a physiotherapist.
• While the healing process is taking place, use an alternative way to exercise where there is no stress placed on the knee, e.g. swimming. Strenuous activity before the knee is completely healed will only lead to complications and possibly permanent damage. 
• If the injury is more severe like a torn ACL or PCL, you may need surgery to reconstruct it. This type of surgery is major but may not always be the best option. People with severe pain or professional athletes who want to regain their previous levels of performance may opt for this complicated and involved surgery.

Prevention of Internal Derangement Knee Injuries

Whilst accidents are hard to predict and hence prevent, there are a few precautions you can take to minimize your chances of injury:

• Keep leg muscles strong and supple by stretching and exercising regularly. These strong supporting muscles will decrease the strain on the knee joint.
• Always warm up muscles appropriately before embarking on further strenuous activity.
• Keep stretching your muscles to maintain their flexibility. This is especially true as you age and tend to neglect your flexibility.
• Try to keep correct form and posture when performing potentially twisting movements to protect your knees.