Knee Pain Causes and Treatment

Knee pain is a common clinic complaint that affects people of all ages or approximately 5% of the adult population and 25% of our athletes.

Knee pain can be the result of an injury, such as a ruptured ACL or torn cartilage. Knee pain can also be caused by underlying medical conditions such as arthritis, gout, and various infections. Osteoarthritis is the most common cause of chronic knee pain in adults over 50 years old.

Most minor knee pain responds well to conservative treatment. Treatment usually consists of therapy, ice, bracing, and over the counter analgesics such as ibuprofen or acetaminophen.

Depending on the cause, knee pain severity and location can vary and may require medical evaluation and treatment. Signs that you likely need to seek medical attention are:

• Cannot bear weight on the leg with the knee pain or your knee feels as if it will buckle (give out) with weight bearing
• Have severe knee swelling
• Unable to fully extend or flex your knee
• Obvious deformity in your leg or knee
• Have a fever, in addition to redness, pain, and swelling in your knee
•  Have severe knee pain that is associated with an injury

Knee pain can be caused by injuries, biomechanical problems, and types of arthritis.

Injuries

A knee injury can affect any of the ligaments, tendons, or fluid-filled sacs (bursae) that surround your knee joint as well as the bones, cartilage, and ligaments that form the joint itself.

Some of the more common knee injuries include:

• ACL injury. A tear of the anterior cruciate ligament (ACL) — one of four ligaments that connect your shinbone to your thighbone. An ACL injury is particularly common in people who play basketball, soccer or other sports that require sudden changes in direction.    
• Fractures. The kneecap (patella), can be broken during motor vehicle collisions or falls. People with Osteoporosis can sometimes sustain a knee fracture simply by stepping wrong.
• Torn meniscus. The meniscus is a tough, rubbery cartilage that acts as a shock absorber between your femur and tibia. It can be torn with sudden twisting of your knee with weight bearing.
• Knee bursitis. Injuries can cause inflammation in the bursae, which are small sacs of fluid that cushion the outside of your knee joint so that tendons and ligaments glide smoothly over the joint.         
• Tendinopathy. Can be acute inflammation (tendinitis) or chronic (tendinosis) of the patellar or quadriceps tendon that attach to the knee cap. Runners, skiers, cyclists, and athletes involved in jumping sports may develop this type of pain. Watch Dr. James Huber's video on FB to learn more about tendinopathies

Biomechanical Problems

• Loose body. Degeneration of bone or cartilage can cause a piece of bone or cartilage to break off and float in the joint space. This may interfere with knee joint movement.
• IT band syndrome. When the tough/fibrous band of tissue that runs from the outside of your hip to the outside of your knee (iliotibial band) becomes very tight that it rubs against the outer portion of your femur. High incidence in distance runners and cyclists.
• Hip or foot pain. If you have hip or foot pain it can change the way you walk. The hip and foot make correction when walking to provide a smooth motion. Pain will cause those joints to work inefficiently and cause more stress on the knee joint.

Arthritic Conditions

More than 100 different types of arthritis exist. The varieties most likely to affect the knee include:

• Osteoarthritis. Also known as degenerative arthritis, is the most common type of arthritis. It's a wear-and-tear condition that occurs when the cartilage in your knee   deteriorates with use and age.
• Rheumatoid arthritis. An autoimmune condition that can affect almost any joint in your body, including your knees. It is a chronic disease and varies in severity.
• Gout. Occurs when uric acid crystals build up in the joint. Most commonly affects the big toe, but it can also occur in the knee.
• Pseudogout. Often mistaken for gout, it is caused by calcium-containing crystals that develop in the joint fluid. Knees are the most common joint affected.
• Septic arthritis. Infection in the knee joint and often occurs with a fever. Usually no trauma before the onset of pain. Can quickly cause extensive damage to the knee cartilage. Requires immediate medical evaluation and treatment.            

Risk Factors

• Being overweight or obese increases stress on your knee joints, even during ordinary activities such as walking or going up and down stairs. Accelerates breakdown of cartilage.     
• Lack flexibility or strength can increase the risk of knee injuries because lack of stability and full range of motion.           
• Certain sports or occupations put greater stress on your knees. Sports such as basketball, skiing, running or jogging all increase a person’s risk of knee injury. Jobs that require repetitive stress on the knees such as construction or farming also can increase your risk.
• Previous injury to the knee makes it more likely that you'll injure your knee again or predispose it to early arthritis.

Not all knee pain is serious. But some knee injuries and medical conditions can lead to increasing pain, joint damage, and disability if left untreated.

Prevention

You cannot always prevent knee pain, however, there are things that can lower your risk.

• Lose weight. Maintain a healthy weight; it's one of the best things you can do for your knees. Every extra 10 pound puts additional 40 pounds of pressure on your knee joints, increasing the risk of injuries and osteoarthritis.
• Get in shape. To prepare your muscles for the demands of sports participation or particular job demands you must take time for conditioning. Work with a coach, trainer, or therapist to ensure that your technique and movement are the best they can be and understand what is necessary to do on a regular basis to strengthen and maintain optimal joint health.
• Balance strength and flexibility. Weak muscles do not support the knee joint adequately and are a leading cause of knee injuries. Build up the muscles that cross the knee joint such as the quadriceps, hamstrings, and calf muscles. Balance and stability training teaches the muscles around your knees work together more effectively.      
• Be smart. If you have arthritic changes to the knee joint from arthritis or other medical condition you will likely need to change the way you exercise. Consider switching to swimming and other low-impact activities a few days of the week. Sometimes limiting high-impact activities may be enough to provide adequate relief.        
   

Treatment

Knee pain can be caused from injury or degeneration of any anatomical structure in the knee (cartilage, ligaments, tendons, bone, muscle, nerves, bursa). When conservative and exercise based treatments fail, further evaluation by a physician is warranted.

Corticosteroid injection. Also known as cortisone injection, is used for bursitis and arthritis conditions around the knee. Therapeutics benefits vary and there is some evidence that repeated injections can cause accelerated degeneration of the knees articular cartilage.      

Regenerative Medicine, including Platelet rich plasma (PRP) and Prolotherapy. These techniques stimulate healing of the damaged tissue by creating an inflammatory response that causes the body to initiate a healing response at the site of injection. The evidence of effectiveness of these techniques is still growing and currently they are not covered by insurances. Despite the lack of evidence many people benefit from these treatments with reduced pain and improved function.          

Percutaneous Ultrasonic Tenotomy. Through a small incision in the skin a specialized needle debrides (cuts away) the diseased/degenerated tissue and causes an inflammatory response that initiates the healing cascade similar to regenerative medicine techniques. This procedure is usually limited to the quadriceps and patellar tendons in the knee.

Hyaluronic Acid. Hyaluronic acid occurs naturally in the body and is found in abundance in the joints and eyes. It is a thick, viscous material that is injected into the knee joint to provide lubrication and pain relief. Usually covered by insurance. Mixed results in the literature and my clinical experience.

Amniotic fluid derivatives. This is a dehydrated cellular component injection that is used to lubricate, reduce inflammation, reduce pain, and protect the knee joint. Preliminary clinical research data is promising and a large multi-center trial is currently ongoing. One brand is covered by Medicare but is usually not covered by other commercial plans.

Nerve ablation. Pain is transmitted to the brain through sensory nerves. There is currently two sets of nerves routinely targeted to help reduce pain. The nerves are only sensory nerves. A process of heating or freezing the nerve is used to temporarily destroy a branch of the nerve providing pain relief. The ablation is preceded by a nerve block to determine which nerves would be appropriate for the procedure. The nerves does  regrow over time and the procedure would likely need to be repeated.                   

Surgery. In cases of acute knee injuries that have ligament or tendon tears or severe arthritis refractory to above treatments, surgical intervention would be required. PCI's Orthopedic Surgeons specialize in knee surgery. Learn more here >>

No treatment for knee pain is 100% effective or guaranteed to work. You should discuss all options with your physician to determine the best treatment choice. Sometimes multiple treatment modalities noted above need to be used to achieve desired result.