Font Size

Knee Pain Overview (cont.)

Causes, Symptoms, Signs, Treatment, Prognosis, and Types of Acute Knee Pain

The nerves that provide sensation to the knee come from the lower back and also provide hip, leg, and ankle sensation. Pain from a deeper injury (called referred pain) can be passed along the nerve to be felt on the surface. Knee pain, therefore, can arise from the knee itself or be referred from conditions of the hip, ankle, or lower back. All of the following sources of knee pain arise from the knee joint itself.

In general, knee pain is either immediate (acute) or long-term (chronic). Acute knee pains can be caused by an acute injury or infection. Chronic knee pains are often from injuries or inflammation (such as arthritis) but can also be caused by infection.

Acute knee pain

  • Fractures (broken bones)
    • Description: Fractures of any of the bones of the knee are traumatic injuries typically caused by moderate to high forces (such as car accidents or contact sports).
    • Symptoms and signs: Fractures may be accompanied by swelling or bruising but are almost always extremely painful and tender. The pain is typically so severe that people are unable to walk or even put weight on the knee.
    • Evaluation: Fractures are an emergency and should be checked by a doctor. This evaluation will generally include an X-ray and other relevant studies. A delay in evaluation can result in fracture fragments being moved and associated injuries.
    • Treatment: Depending on the particular fracture, the doctor may either recommend immobilization (with a cast or splint) or surgery to repair it.
    • Prognosis: Fractures often heal with no long-term problems. Some fractures, however, are complicated by arthritis or by injuries to arteries or nerves that can be serious.
  • Sprained and torn collateral ligaments
    • Description: The medial collateral ligament (MCL) is the most commonly injured ligament in the knee. Like all ligaments, this ligament may be sprained or torn. A sprained ligament may be partially ruptured. A torn ligament is completely ruptured.
    • Symptoms and signs: Severe MCL sprains or tears often produce a tearing or ripping sensation along the inner joint line of the knee. You may also notice knee instability and swelling. A force from the outer (lateral) knee to the inner (medial) knee is typically responsible for this injury in contrast to the more rarely injured LCL, which is typically a result of an inner to outer force. In general, bruises
    • occur at the point of impact. Sprained and torn ligaments occur opposite the point of impact. Both MCL and LCL injuries are common in contact sports but can also result from twisting the knee with a planted foot such as in skiing. Injured medial and lateral collateral ligaments are typically tender at the inner and outer knee respectively.
    • Evaluation: After a history and physical examination, conservative treatment with rest, application of cold packs, and elevation of the involved extremity is often recommended. With persisting symptoms, the doctor may suggest an MRI scan or arthroscopy to further evaluate an injured ligament.
    • Treatment: For a mild sprain, early rehabilitation with compression, ice, elevation, anti-inflammatories, and pain-control medications along with an exercise
    • regimen including a stationary bike and leg-strengthening exercises may be all you need. Such an exercise regimen should be under the supervision of a doctor or physical therapist because certain exercises are to be avoided. In contrast to sprains, tears often require surgical repair for best results.
    • Prognosis: The long-term outlook for ligament injury depends on the severity of the injury and the recovery from any surgical repair.
  • Sprained and torn cruciate ligaments
    • Description: An anterior cruciate ligament (ACL) injury is a common sports injury generally caused by a hard stop or a violent twisting of the knee. The posterior cruciate ligament (PCL) is stronger than the ACL and much less commonly torn. The PCL requires strong forces, such as those produced when the dashboard strikes the knee in a car accident, to tear. Due to these severe forces, PCL injury is often associated with other ligament and bone injuries.
    • Symptoms and signs: If you tear your ACL, you may hear a pop. You will also notice your knee give way or become unstable and feel pain.. This will, almost always, be followed by marked knee swelling over the next couple of hours because the ACL bleeds briskly when torn.
    • Treatment: Surgical repair is recommended for athletes who require return to competition. Conservative treatment and knee braces may prove sufficient for those who do not demand quite so much from their knees.
Medically Reviewed by a Doctor on 2/19/2016

Must Read Articles Related to Knee Pain Overview

Chronic Pain
Chronic Pain Chronic pain is pain that persists for a period of six months or longer, and is the result of a long-standing medical condition(s) or damage to the body. Common...learn more >>
Gout Gout is characterized by abnormal uric acid learn more >>
Knee Joint Replacement
Knee Joint Replacement The procedure of knee joint replacement is called a total knee arthroplasty (TKA). This surgery involves replacing your knee joint with a manmade one. Osteoarth...learn more >>

Patient Comments & Reviews

The eMedicineHealth doctors ask about Knee Pain:

Knee Pain - Causes

What was the cause of your knee pain?

Knee Pain - Length Symptoms Lasted

How long did the symptoms of your knee pain last? Was there anything in particular that helped with pain/symptom relief?

Knee Pain - Experience

Tell us about your experience with knee pain.

Read What Your Physician is Reading on Medscape

Knee Injury, Soft Tissue »

Soft tissue injuries of the knee are some of the most common and clinically challenging musculoskeletal disorders in patients presenting to the ED.

Read More on Medscape Reference »

Medical Dictionary