The knees provide stable support for the body. They also allow the legs to bend and straighten. Both flexibility and stability are needed to stand, walk, run, crouch, jump, and turn. Other parts of the body help the knees do their job. These are:
Knee injury facts
- The knee is one of the most common body parts to be injured.
- Types of knee injuries include sprains, strains, bursitis, dislocations, fractures, meniscus tears, and overuse injuries.
- Knee injuries are generally caused by twisting or bending force applied to the knee, or a direct blow, such as from sports, falls, or accidents.
- Risk factors for knee injury include overuse, improper training, having osteoporosis, and playing high-impact sports that involve sudden changes in direction.
- The main signs and symptoms of knee injury are pain and swelling.
- Knee injuries are diagnosed by a history and physical. Sometimes an X-ray or MRI may be done.
- Treatment of knee injuries depends on the type and severity of the injury and can involve RICE therapy (rest, ice, compression, elevation), physical therapy, immobilization, or surgery.
- Prognosis for knee injury depends on the type and severity of the injury and the need for physical therapy or surgery.
- Knee injuries can be prevented by proper training, proper equipment, and maintaining a safe playing field or home environment to avoid falls.
Who Gets Knee Problems?
Men, women, and children can have knee problems. They occur in people of all races and ethnic backgrounds.
What Causes Knee Problems?
Mechanical knee problems can be caused by:
- A direct blow or sudden movements that strain the knee
- Osteoarthritis in the knee, resulting from wear and tear on its parts.
- Inflammatory knee problems can be caused by certain rheumatic diseases, such as rheumatoid arthritis and systemic lupus erythematosus (lupus). These diseases cause swelling that can damage the knees permanently.
How Are Knee Problems Diagnosed?
Doctors diagnose knee problems by using:
- Medical history
- Physical examination
- Diagnostic tests (such as x rays, bone scan, CAT scan, MRI, arthroscopy, and biopsy).
- Arthritis in the Knees
The most common type of arthritis of the knee is osteoarthritis. In this disease, the cartilage in the knee gradually wears away. Treatments for osteoarthritis are:
- Medicines to reduce pain, such as aspirin and acetaminophen
- Medicines to reduce swelling and inflammation, such as ibuprofen and nonsteroidal anti-inflammatory drugs (NSAIDs)
- Exercises to improve movement and strength
- Weight loss
Rheumatoid arthritis is another type of arthritis that affects the knee. In rheumatoid arthritis, the knee becomes inflamed and cartilage may be destroyed. Treatment includes:
- Physical therapy
- Knee replacement surgery (for a seriously damaged knee).
- Cartilage Injuries and Disorders
Chondromalacia (KON-dro-muh-lay-she-uh) occurs when the cartilage of the knee cap softens. This can be caused by injury, overuse, or muscle weakness, or if parts of the knee are out of alignment. C
hondromalacia can develop if a blow to the knee cap tears off a piece of cartilage or a piece of cartilage containing a bone fragment.
The meniscus (meh-NISS-kus) is a C-shaped piece of cartilage that acts like a pad between the femur (thigh bone) and tibia (shin bone).
It is easily injured if the knee is twisted while bearing weight. A partial or total tear may occur. If the tear is tiny, the meniscus stays connected to the front and back of the knee.
If the tear is large, the meniscus may be left hanging by a thread of cartilage. The seriousness of the injury depends on the location and the size of the tear.
Treatment for cartilage injuries includes:
- Exercises to strengthen muscles
- Electrical stimulation to strengthen muscles
- Surgery for severe injuries.
What are risk factors for a knee injury?
High-impact sports, including running, basketball, football, hockey, soccer, cycling, and others, can increase the risk of knee injury.
Sports where shoes with cleats are worn and sharp, sudden changes in direction are made are common risks for knee injury.
The elderly may be at higher risk for knee injury due to falls and osteoporosis.
Women may be at higher risk for particular knee injuries to the anterior cruciate ligament (ACL) and patella. This is due to the anatomy of a woman’s hips and femur and the angle at which the knee is tilted.
This can lead to chondromalacia patella (CMP), an inflammation or irritation of the underside of the patella.
Being overweight can be a risk factor for knee injury, as excess weight puts more stress on the lower extremity joints.
Overuse and overtraining, improper or insufficient training for a sport, or not properly rehabilitating acute injuries can also predispose a person to knee injuries.
What are knee injury symptoms and signs?
The symptoms and signs of knee injury are related to the type of injury and the part of the knee that was injured.
The main symptoms of knee injury are as follows:
- Difficulty bending the knee
- Problems weight bearing
- Clicking or popping sounds
- Locking of the knee
- Feeling of instability
If the injury is acute, the main symptoms will most likely be pain and swelling. If the injury is chronic or from overuse, the symptoms of clicking, popping, and intermittent pain will be more prominent.
How is a knee injury diagnosed?
Knee injuries are diagnosed by the physician on the basis of history, physical examination, and sometimes the use of X-rays or MRIs.
Depending on the how the knee was injured and whether or not there are accompanying medical issues, the doctor will perform specific tests involving bending or twisting the knee to test the stability of the ligaments and check for damage to the cartilage.
Knee-bending tests done by your doctor are designed to isolate specifically which ligament or part of the cartilage has been damaged.
Further testing with X-rays, CT scans, or MRIs may be necessary to evaluate the extent of the injury and help determine treatment and prognosis.
X-rays and CT scans are used to asses for bony injuries (fractures), and MRIs are used to evaluate soft-tissue damage (ligaments and cartilage).
How Can People Prevent Knee Problems?
Some knee problems (such as those resulting from an accident) can’t be prevented. But many knee problems can be prevented by doing the following:
- Warm up before playing sports. Walking and stretching are good warm-up exercises. Stretching the muscles in the front and the back of the thighs is a good way to warm up the knees.
- Make the leg muscles strong by doing certain exercises (for example, walking up stairs, riding a stationary bicycle, or working out with weights).
- Avoid sudden changes in the intensity of exercise.
- Increase the force or duration of activity slowly.
- Wear shoes that fit and are in good condition.
- Maintain a healthy weight. Extra weight puts pressure on the knees.
What Types of Exercise Are Best for Someone With Knee Problems?
Three types of exercise are best for people with arthritis:
- Range-of-motion exercises. These exercises help maintain or increase flexibility. They also help relieve stiffness in the knee.
- Strengthening exercises. These exercises help maintain or increase muscle strength. Strong muscles help support and protect joints with arthritis.
- Aerobic or endurance exercises. These exercises improve heart function and blood circulation. They also help control weight. Some studies show that aerobic exercise can reduce swelling in some joints.