Internal Derangement of the Knee: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Internal Derangement of the Knee?
An orthopedic surgeon, a doctor who treats bone and joint problems, usually treats injuries inside the knee. A sports medicine doctor, who treats sports injuries, may also help. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is internal derangement of the knee?
The knee joint is made up of bone, cartilage, ligaments and fluid. When any of these parts is hurt or diseased, you have knee problems.
This topic covers common knee injuries, such as tears of soft tissues (for example ligaments and the meniscus), fractures, and dislocation. In many cases, an injury involves more than one part of the knee.
Symptoms
Pain and swelling are the most common signs of a knee injury. The knee may also catch or lock.
Some injuries, such as an ACL tear, cause instability, the feeling that your knee is giving way.
The most common signs of a meniscus tear are:
- Pain.
- Stiffness and swelling.
- Catching or locking of the knee.
- The feeling that the knee is giving way.
- Not being able to move the knee through its full range of motion.
You might feel a pop when you tear the meniscus. Over 2 to 3 days, the knee will gradually become stiffer and more swollen.
Causes and who gets it
Sudden tears of the meniscus often happen during sports. They can occur when twisting, cutting, pivoting, or being tackled. Tears may also occur as a result of arthritis or aging.
ACL injuries are more likely to occur in athletes who play cutting and pivoting sports like soccer, football, and basketball. Changing direction rapidly or landing from a jump incorrectly can tear the ACL.
The posterior cruciate ligament is often injured from a blow to the front of the knee while the knee is bent. Injuries to the collateral ligaments on the sides of the knee are usually caused by a force that pushes the knee sideways.
The most common disease affecting the knee is osteoarthritis. In osteoarthritis, the cartilage in the knee gradually wears away, causing pain and swelling.
How doctors diagnose it
After talking with you about your symptoms and medical history, your doctor will examine your knee. For a meniscus tear, the doctor checks for tenderness along the joint line where the meniscus sits. In the McMurray test, your doctor bends your knee, then straightens and rotates it.
An X-ray will not show a meniscus tear, but it can help look for other causes of knee pain, such as osteoarthritis. An MRI shows the soft tissues in your knee joint, including the menisci, cartilage, tendons, and ligaments. MRI is the preferred method of diagnosing sudden meniscus tears because of its high level of accuracy.
Treatment
Many knee injuries can be successfully treated with simple measures, such as bracing and rehabilitation exercises. Other injuries may need surgery.
At first, the RICE plan can help speed recovery. It stands for rest, ice, compression, and elevation.
Medicines called NSAIDs, like ibuprofen and naproxen, reduce pain and swelling. A doctor may also inject a corticosteroid medicine into the knee joint to help eliminate pain and swelling. Physical therapy uses exercises to restore function to the knee and strengthen the leg muscles that support it.
The outer one-third of the meniscus has a rich blood supply. A tear there may heal on its own or can often be repaired with surgery. The inner two-thirds lacks a significant blood supply, so tears there cannot heal.
If symptoms persist with nonsurgical treatment, a doctor may suggest arthroscopic surgery. The surgeon puts a small camera and tools into the knee through small cuts. A partial meniscectomy trims away the damaged meniscus tissue. Some tears can be repaired by stitching the torn pieces together.
Recovery after a meniscus repair takes longer than after a partial meniscectomy.
When to see a doctor
Call 911 or go to the emergency room if a sudden injury causes severe pain, a deep or large wound, or bleeding that will not stop.
Seek treatment as soon as possible, especially if you hear a popping noise and feel your knee give out when you are hurt, cannot move the knee, begin limping, or have swelling at the injury site.
See a doctor if your symptoms affect how your knee feels or works, or do not go away on their own. Some injuries can raise your risk of developing arthritis.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can examine your knee and help decide which tests you need. They can also help coordinate care with an orthopedic specialist and follow your progress.
Common questions
Can a torn meniscus heal on its own?
Sometimes it can, depending on where the tear is. Tears in the inner part, with limited blood flow, cannot heal. Many meniscus tears will not need immediate surgery.
Does every knee injury need surgery?
No, many knee injuries can be treated without surgery.
What is the most common disease that affects the knee?
The most common disease affecting the knee is osteoarthritis. In this disease, the cartilage in the knee gradually wears away, causing pain and swelling.
How long is recovery after meniscus surgery?
It depends on the type of surgery. Rehabilitation time for a meniscus repair is about 3 to 6 months. A partial meniscectomy requires approximately 3 to 6 weeks of healing.
Sources
- American Academy of Orthopaedic Surgeons - OrthoInfo - Common Knee Injuries
- American Academy of Orthopaedic Surgeons - OrthoInfo - Meniscus Tears
- MedlinePlus - Knee Injuries and Disorders
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
