Child Health Library
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Knee Problems and Injuries
Most people have had a minor knee problem at one time or another. Most of the time our body movements do not cause problems, but it's not surprising that symptoms develop from everyday wear and tear, overuse, or injury. Knee problems and injuries most often occur during sports or recreational activities, work-related tasks, or home projects.
The knee is the largest joint in the body. The upper and lower bones of the knee are separated by two discs (menisci). The upper leg bone (femur) and the lower leg bones (tibia and fibula) are connected by ligaments, tendons, and muscles. The surface of the bones inside the knee joint is covered by articular cartilage, which absorbs shock and provides a smooth, gliding surface for joint movement. See a picture of the structures of the knee.
Although a knee problem is often caused by an injury to one or more of these structures, it may have another cause. Some people are more likely to develop knee problems than others. Many jobs, sports and recreation activities, getting older, or having a disease such as osteoporosis or arthritis increase your chances of having problems with your knees.
Sudden (acute) injuries
Injuries are the most common cause of knee problems. Sudden (acute) injuries may be caused by a direct blow to the knee or from abnormal twisting, bending the knee, or falling on the knee. Pain, bruising, or swelling may be severe and develop within minutes of the injury. Nerves or blood vessels may be pinched or damaged during the injury. The knee or lower leg may feel numb, weak, or cold; tingle; or look pale or blue. Acute injuries include:
- Sprains, strains, or other injuries to the ligaments and tendons that connect and support the kneecap.
- A tear in the rubbery cushions of the knee joint (meniscus).
- Ligament tears, such as the anterior cruciate ligament (ACL). The medial collateral ligament (MCL) is the most commonly injured ligament of the knee.
- Breaks (fracture) of the kneecap, lower portion of the femur, or upper part of the tibia or fibula. Knee fractures are most commonly caused by abnormal force, such as a falling on the knee, a severe twisting motion, severe force that bends the knee, or when the knee forcefully hits an object.
- Kneecap dislocation. This type of dislocation occurs more frequently in 13- to 18-year-old girls.
- Pieces of bone or tissue (loose bodies) from a fracture or dislocation that may get caught in the joint and interfere with movement.
- Knee joint dislocation. This is a rare injury that requires great force. It is a serious injury and requires immediate medical care.
Overuse injuries occur with repetitive activities or repeated or prolonged pressure on the knee. Activities such as stair climbing, bicycle riding, jogging, or jumping stress joints and other tissues and can lead to irritation and inflammation. Overuse injuries include:
- Inflammation of the small sacs of fluid that cushion and lubricate the knee (bursitis).
- Inflammation of the tendons (tendinitis) or small tears in the tendons (tendinosis).
- Thickening or folding of the knee ligaments (plica syndrome).
- Pain in the front of the knee from overuse, injury, excess weight, or problems in the kneecap (patellofemoral pain syndrome).
- Irritation and inflammation of the band of fibrous tissue that runs down the outside of the thigh (iliotibial band syndrome).
Conditions that may cause knee problems
Problems not directly related to an injury or overuse may occur in or around the knee.
- Osteoarthritis (degenerative joint disease) may cause knee pain that is worse in the morning and improves during the day. It often develops at the site of a previous injury. Other types of arthritis, such as rheumatoid arthritis, gout, and lupus, also can cause knee pain, swelling, and stiffness.
- Osgood-Schlatter disease causes pain, swelling, and tenderness in the front of the knee below the kneecap. It is especially common in boys ages 11 to 15.
- A popliteal (or Baker's) cyst causes swelling in the back of the knee.
- Infection in the skin (cellulitis), joint (infectious arthritis), bone (osteomyelitis), or bursa (septic bursitis) can cause pain and decreased knee movement.
- A problem elsewhere in the body, such as a pinched nerve or a problem in the hip, can sometimes cause knee pain.
- Osteochondritis dissecans causes pain and decreased movement when a piece of bone or cartilage or both inside the knee joint loses blood supply and dies.
Treatment for a knee problem or injury may include first aid measures, rest, bracing, physical therapy, medicine, and, in some cases, surgery. Treatment depends on the location, type, and severity of the injury as well as your age, health condition, and activity level (such as work, sports, or hobbies).
Check your symptoms to decide if and when you should see a doctor.
Check Your Symptoms
The medical assessment of symptoms is based on the body parts you have.
- If you are transgender or nonbinary, choose the sex that matches the body parts (such as ovaries, testes, prostate, breasts, penis, or vagina) you now have in the area where you are having symptoms.
- If your symptoms aren’t related to those organs, you can choose the gender you identify with.
- If you have some organs of both sexes, you may need to go through this triage tool twice (once as "male" and once as "female"). This will make sure that the tool asks the right questions for you.
Many things can affect how your body responds to a symptom and what kind of care you may need. These include:
- Your age. Babies and older adults tend to get sicker quicker.
- Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
- Medicines you take. Certain medicines, herbal remedies, and supplements can cause symptoms or make them worse.
- Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
- Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.
Try Home Treatment
You have answered all the questions. Based on your answers, you may be able to take care of this problem at home.
- Try home treatment to relieve the symptoms.
- Call your doctor if symptoms get worse or you have any concerns (for example, if symptoms are not getting better as you would expect). You may need care sooner.
Pain in adults and older children
- Severe pain (8 to 10): The pain is so bad that you can't stand it for more than a few hours, can't sleep, and can't do anything else except focus on the pain.
- Moderate pain (5 to 7): The pain is bad enough to disrupt your normal activities and your sleep, but you can tolerate it for hours or days. Moderate can also mean pain that comes and goes even if it's severe when it's there.
- Mild pain (1 to 4): You notice the pain, but it is not bad enough to disrupt your sleep or activities.
Major trauma is any event that can cause very serious injury, such as:
- A fall from more than 10 ft (3.1 m)[more than 5 ft (1.5 m) for children under 2 years and adults over 65].
- A car crash in which any vehicle involved was going more than 20 miles (32 km) per hour.
- Any event that causes severe bleeding that you cannot control.
- Any event forceful enough to badly break a large bone (like an arm bone or leg bone).
When an area turns blue, very pale, or cold, it can mean that there has been a sudden change in the blood supply to the area. This can be serious.
There are other reasons for color and temperature changes. Bruises often look blue. A limb may turn blue or pale if you leave it in one position for too long, but its normal color returns after you move it. What you are looking for is a change in how the area looks (it turns blue or pale) and feels (it becomes cold to the touch), and this change does not go away.
Pain in children under 3 years
It can be hard to tell how much pain a baby or toddler is in.
- Severe pain (8 to 10): The pain is so bad that the baby cannot sleep, cannot get comfortable, and cries constantly no matter what you do. The baby may kick, make fists, or grimace.
- Moderate pain (5 to 7): The baby is very fussy, clings to you a lot, and may have trouble sleeping but responds when you try to comfort him or her.
- Mild pain (1 to 4): The baby is a little fussy and clings to you a little but responds when you try to comfort him or her.
Pain in children 3 years and older
- Severe pain (8 to 10): The pain is so bad that the child can't stand it for more than a few hours, can't sleep, and can't do anything else except focus on the pain. No one can tolerate severe pain for more than a few hours.
- Moderate pain (5 to 7): The pain is bad enough to disrupt the child's normal activities and sleep, but the child can tolerate it for hours or days.
- Mild pain (1 to 4): The child notices and may complain of the pain, but it is not bad enough to disrupt his or her sleep or activities.
Symptoms of infection may include:
- Increased pain, swelling, warmth, or redness in or around the area.
- Red streaks leading from the area.
- Pus draining from the area.
- A fever.
Certain health conditions and medicines weaken the immune system's ability to fight off infection and illness. Some examples in adults are:
- Diseases such as diabetes, cancer, heart disease, and HIV/AIDS.
- Long-term alcohol and drug problems.
- Steroid medicines, which may be used to treat a variety of conditions.
- Chemotherapy and radiation therapy for cancer.
- Other medicines used to treat autoimmune disease.
- Medicines taken after organ transplant.
- Not having a spleen.
With severe bleeding, any of these may be true:
- Blood is pumping from the wound.
- The bleeding does not stop or slow down with pressure.
- Blood is quickly soaking through bandage after bandage.
With moderate bleeding, any of these may be true:
- The bleeding slows or stops with pressure but starts again if you remove the pressure.
- The blood may soak through a few bandages, but it is not fast or out of control.
With mild bleeding, any of these may be true:
- The bleeding stops on its own or with pressure.
- The bleeding stops or slows to an ooze or trickle after 15 minutes of pressure. It may ooze or trickle for up to 45 minutes.
Shock is a life-threatening condition that may quickly occur after a sudden illness or injury.
Adults and older children often have several symptoms of shock. These include:
- Passing out (losing consciousness).
- Feeling very dizzy or lightheaded, like you may pass out.
- Feeling very weak or having trouble standing.
- Not feeling alert or able to think clearly. You may be confused, restless, fearful, or unable to respond to questions.
Shock is a life-threatening condition that may occur quickly after a sudden illness or injury.
Babies and young children often have several symptoms of shock. These include:
- Passing out (losing consciousness).
- Being very sleepy or hard to wake up.
- Not responding when being touched or talked to.
- Breathing much faster than usual.
- Acting confused. The child may not know where he or she is.
Seek Care Now
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
- Call your doctor now to discuss the symptoms and arrange for care.
- If you cannot reach your doctor or you don't have one, seek care in the next hour.
- You do not need to call an ambulance unless:
- You cannot travel safely either by driving yourself or by having someone else drive you.
- You are in an area where heavy traffic or other problems may slow you down.
Make an Appointment
Based on your answers, the problem may not improve without medical care.
- Make an appointment to see your doctor in the next 1 to 2 weeks.
- If appropriate, try home treatment while you are waiting for the appointment.
- If symptoms get worse or you have any concerns, call your doctor. You may need care sooner.
Seek Care Today
Based on your answers, you may need care soon. The problem probably will not get better without medical care.
- Call your doctor today to discuss the symptoms and arrange for care.
- If you cannot reach your doctor or you don't have one, seek care today.
- If it is evening, watch the symptoms and seek care in the morning.
- If the symptoms get worse, seek care sooner.
Call 911 Now
Based on your answers, you need emergency care.
Call 911 or other emergency services now.
Call 911 Now
Based on your answers, you need emergency care.
Call 911 or other emergency services now.
Put direct, steady pressure on the wound until help arrives. Keep the area raised if you can.
Home treatment may help relieve pain, swelling, and stiffness.
- Rest and protect an injured or sore area. Stop, change, or take a break from any activity that may be causing your pain or soreness. When resting, place a small pillow under your knee.
- Ice will reduce pain and swelling. Apply ice or cold packs immediately to prevent or minimize swelling. Apply the ice or cold pack for 10 to 20 minutes, 3 or more times a day.
- For the first 48 hours after an injury, avoid things that might increase swelling, such as hot showers, hot tubs, hot packs, or alcoholic beverages.
- After 48 to 72 hours, if swelling is gone, apply heat and begin gentle exercise with the aid of moist heat to help restore and maintain flexibility. Some experts recommend alternating between heat and cold treatments.
- Compression, or wrapping the injured or sore area with an elastic bandage (such as an Ace wrap), will help decrease swelling.
- Don't wrap it too tightly, since this can cause more swelling below the affected area. Loosen the bandage if it gets too tight. Signs that the bandage is too tight include numbness, tingling, increased pain, coolness, or swelling in the area below the bandage.
- Don't expect the bandage to protect or stabilize a knee injury.
- Talk to your doctor if you think you need to use a wrap for longer than 48 to 72 hours. A more serious problem may be present.
- Elevate the injured or sore area on pillows while applying ice and anytime you are sitting or lying down. Try to keep the area at or above the level of your heart to help minimize swelling.
- Reduce stress on your sore knee (until you can get advice from your doctor):
- Use a cane or crutch in the hand opposite your painful knee.
- Use two crutches, keeping weight off the leg with the sore knee. You can get canes or crutches from most pharmacies. Crutches are recommended if a cane causes you to walk with a limp.
- Gently massage or rub the area to relieve pain and encourage blood flow. Do not massage the injured area if it causes pain.
- Try the following exercises to maintain flexibility:
- Avoid high-impact exercise, such as running, skiing, snowboarding, or playing tennis, until your knee is no longer painful or swollen.
Do not smoke. Smoking slows healing because it decreases blood supply and delays tissue repair. For more information, see the topic Quitting Smoking.
Try a nonprescription medicine to help treat your fever or pain:
Talk to your child's doctor before switching back and forth between doses of acetaminophen and ibuprofen. When you switch between two medicines, there is a chance your child will get too much medicine.
Be sure to follow these safety tips when you use a nonprescription medicine:
Symptoms to watch for during home treatment
Call your doctor if any of the following occur during home treatment:
- Signs of infection develop.
- Your knee becomes hard to move or swelling lasts for more than 2 days.
- Your knee, lower leg, or foot becomes pale or cool or looks blue.
- Symptoms do not improve with home treatment.
- Symptoms become more severe or frequent.
The following tips may prevent knee problems.
General prevention tips
- Wear your seat belt in a motor vehicle.
- Don't carry objects that are too heavy. Use a step stool. Do not stand on chairs or other unsteady objects.
- Wear knee guards during sports or recreational activities, such as roller-skating or soccer.
- Stretch before and after physical exercise, sports, or recreational activities to warm up your muscles.
- Use the correct techniques or positions during activities so that you do not strain your muscles.
- Use equipment appropriate to your size, strength, and ability. Avoid repeated movements that can cause injury. In daily routines or hobbies, look at activities in which you make repeated knee movements.
- Consider taking lessons to learn the proper technique for sports. Have a trainer or person who is familiar with sports equipment check your equipment to see if it is well suited for your level of ability, body size, and body strength.
- If you feel that certain activities at your workplace are causing pain or soreness from overuse, call your human resources department for information on other ways of doing your job or to talk about using different equipment.
Tips specific to the knee
- Keep your knees and the muscles that support them strong and flexible. Warm up before activities. Try the following stretches:
- Avoid activities that stress your knees, such as deep knee bends or downhill running.
- Wear shoes with good arch supports.
- Do not wear high-heeled shoes.
- When playing contact sports, wear the right shoes that are made for the surface you are playing or running on, such as a track or tennis court.
- Replace running shoes every 300 to 500 miles (480 to 800 kilometers). Experts recommend getting new athletic shoes every 3 months or after 500 miles of wear.
Tips specific to female athletes
Sports trainers recommend training programs that help women learn to run, jump, and pivot with knees bent to avoid knee injuries. In sports such as soccer, basketball, and volleyball, women who bend their knees and play low to the ground have fewer knee injuries than women who run and pivot with stiff legs.
Knee brace use
Some people use knee braces to prevent knee injuries or after a knee injury. There are many types of knee braces, from soft fabric sleeves to rigid, metal hinged braces, that support and protect the knee. If your doctor has recommended the use of a knee brace, follow his or her instructions. If you are using a knee brace to help prevent problems, follow the manufacturer's instructions for use.
Keep bones strong
- Eat healthy foods such as milk, cheese, yogurt, and dark green, leafy vegetables like broccoli. For more information, see the topic Healthy Eating.
- Exercise and stay active. Talk to your doctor about exercises and activities that are right for you. Begin slowly, especially if you have been inactive. For more information, see the topic Fitness.
- Don't drink more than 2 alcoholic drinks a day if you are a man, or 1 alcoholic drink a day if you are a woman. Drinking alcohol increases your chances of having weak bones (osteoporosis). It also increases your chances of falling.
- Do not smoke or use other tobacco products. Smoking increases your chances of having osteoporosis. It also causes problems with the blood supply in your legs and slows healing. For more information, see the topic Quitting Smoking.
Knee injuries such as bruises, burns, fractures, cuts, or punctures may be caused by abuse. Suspect possible abuse when an injury cannot be explained or does not match the explanation, repeated injuries occur, or the explanations for the cause of the injury change. You may be able to prevent further abuse by reporting it and seeking help.
Preparing For Your Appointment
To prepare for your appointment, see the topic Making the Most of Your Appointment.
You can help your doctor diagnose and treat your condition by being prepared to answer the following questions:
- What are your main symptoms?
- How long have you had your symptoms?
- What were you doing when your symptoms started?
- Have you had this problem in the past?
- What was the diagnosis?
- How was it treated?
- How and when did an injury occur? How was it treated? Were illegal drugs or alcohol involved in your injury?
- Have you had any injuries in the past to the same area? Do you have any continuing problems because of the previous injury?
- Have you ever had knee surgery?
- What activities, related to sports, work, or your lifestyle, make your symptoms better or worse?
- Do you think that activities related to your job or hobbies caused your symptoms?
- What home treatment measures have you tried? Did they help?
- What nonprescription medicines have you taken? Did they help?
- Do you have any health risks?
Current as ofJune 26, 2019
Author: Healthwise Staff
Medical Review: William H. Blahd Jr. MD, FACEP - Emergency Medicine
Kathleen Romito MD - Family Medicine
Adam Husney MD - Family Medicine
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