Knee Pain from Arthritis
What causes knee pain?
Knee pain can occur from several anatomical structures that can be injured or inflamed. Understanding the anatomy, listening to the history of the problem from the patient, performing a comprehensive examination of the knee structures and function, and reviewing proper imaging of the knee (x-rays, MRIs) will help lead to the correct diagnosis. In some cases, blood examination is a key part of the evaluation of some inflammatory conditions. Certain conditions require drawing fluid from the knee (a joint aspiration) to help provide the correct diagnosis, such as in the case of infections or gout.
Tendonitis occurs at the end of a muscle where it connects to a bone when it becomes acutely inflamed. This causes pain in the area of the tendon insertion when the muscle is being used. In the knee, there are many locations where muscles are connecting from the quadriceps muscles, the hamstring muscles, and the calf muscles that can cause knee pain when walking, running, rising and sitting, and stair climbing.
Tendinosis occurs when the tendon has been chronically inflamed and the fibers of the tendon develop micro-tears and swelling in them.
Tendon rupture is when a tendon tears acutely. The rupture can be complete or partial. In the knee, the quadriceps tendon is one of the more common tendon ruptures. In a complete tear, this causes an inability to extend the knee or walk without the leg giving out and requires surgical repair. There is also associated bleeding in the joint that can cause swelling and pain. Partial tears can be managed sometimes without surgery using braces to protect the tendon and can be augmented to heal using biologic injections.
Bursas are anatomic cushions at tendon insertions that can become inflamed and cause knee paint at their locations.
Ligaments connect bones to bones in the knee and act as static stabilizers that can be injured, stretched, or torn. The four main ligaments in the knee are the ACL, PCL, MCL, LCL. When these ligaments are injured, the stability of the knee is compromised and can cause pain and swelling.
- ACL tears are often repaired by replacing the ligament with another ligament or similar tissue from the patient or a donor patient.
- Complete PCL tears in young active patients are often repaired.
- MCL tears are commonly incomplete tears and can heal with bracing and protection without surgery. Some complete tears require surgical repair.
Medial and Lateral Meniscus cartilage injuries can cause pain when they are torn in small or large areas. These cartilaginous shock absorbers are critical in the transfer of load across the knee and protection of the surface cartilage on the ends of bones.
Articular surface cartilage damage from trauma, arthritis, infection, and osteonecrosis can cause pain, swelling, loss of motion, and deformity of the knee.
Arthritis is the general term for joint inflammation. Arthritis usually causes pain, swelling, stiffness, loss of motion and reduction in activity level when it occurs in the knee. Treatment depends on the type of arthritis each person presents with. This can be the result of many disease processes in the knee, which include:
- Osteoarthritis (degenerative cartilage wear-down condition)
- Rheumatoid arthritis (inflammatory cartilage destructive disease)
- Psoriatic arthritis (inflammatory cartilage destructive disease)
- Gout (crystalline deposit disease from uric acid levels that are elevated)
- Infections (bacterial, viral, fungal, Lyme Disease)
Osteonecrosis means “bone death”. The bone cells die due to blood flow reduction, lack of oxygen to the cells, and the bone begins to cause pain. This can occur in any bone, but it is commonly seen in the knee and hip joints. It is most often associated with steroid use, alcohol use, sickle cell disease, and it can occur spontaneously. It is commonly seen on the end of the femur and more often on the inner side (medial side).
As osteonecrosis advances and the underlying bone dies, the surface coating on the knee joint called the cartilage can eventually collapse down into the underlying bone causing more pain and disability requiring joint replacement.
Synovitis is a condition inside the knee joint when the lining tissues become inflamed. The inner lining of the knee joint is called the synovium. A variety of conditions can activate this lining to become more active in producing synovial fluid, which is the lubricating fluid of the knee joint. With chronic activation, this lining can become swollen and thick and chronically produce too much joint fluid, creating knee pain and loss of motion from the fluid pressure.
What are the symptoms of knee pain from arthritis?
The common symptom of knee pain from arthritis are:
- Pain in the knee that a person can point to on one side of the knee or the other, or just under the kneecap. (This can be an indication to be a candidate for partial knee replacement)
- Pain that is located all around the knee, not on just one side or under the kneecap alone. (This can be an indication to be a candidate for total knee replacement)
- Pain in the knee when walking.
- Pain getting up from a seated position.
- Pain going up and/or downstairs.
- Dull or aching pain
- Stiffness in the knee
- Swelling of the knee joint.
- Loss of motion in the knee.
- Decreased walk distance
- Reduction in activities of daily living
- Reduction in sports and exercise activities.
How do you treat knee pain from arthritis?
Knee pain from arthritis has many treatment options including non-surgical and surgical options. It is best to begin with the least invasive lowest risk options that give the greatest pain relief and improvement of function. When the less risky and less invasive options no longer provide relief, then more advanced treatment options are considered.
What makes someone a knee arthritis doctor?
The doctor who is most educated in the evaluation, diagnosis, and treatment of knee pain, arthritis and injuries is an orthopaedic surgeon. This requires graduation from a 4-year program in medical school in the USA. Then the acceptance into, and completion of, an orthopaedic surgery residency program for 5 years in the USA. Many orthopaedic surgeons will then complete further specialization in a fellowship program after residency. In the case of knee surgeons, this is in joint replacement or sports medicine.
These surgeons are skilled at the physical examination of the knee, ordering and evaluating proper imaging studies (x-rays, MRI, CT Scans, ultrasound, bone scans), ordering and interpreting laboratory studies, creating management plans to treat knee conditions identified, referring patients for further evaluations by other specialists, and performing surgical procedures on the knee as required by the individual patient’s situation.
What do you recommend for knee arthritis pain management specifically?
I agree with the options that the American Academy of Orthopaedic Surgeons recommends in the management of osteoarthritis of the knee. Their recommendations are based on “outcomes-based medicine” from research conducted and reported in the peer review literature. I also believe in the advancement of medicine, and newer techniques and therapies available to knee surgeons. Some of these options include biologic treatments like stem cells and blood-derived growth factors, and some include advanced technology surgical treatments such as robotic-assisted surgery during joint replacement.
Can you leave knee pain from arthritis untreated?
Yes, you can leave knee pain from osteoarthritis untreated. Unlike cancer or heart disease, osteoarthritis left untreated will not shorten your life. However, it will reduce your quality of life. Managing your quality of life, reducing pain and increasing function is what treating knee osteoarthritis is all about. There are non-surgical and surgical ways to treat knee osteoarthritis. As far as leaving knee pain in general untreated, first I believe you should diagnose the problem and discuss the treatment options with each patient. Only after discussing the options with the patient should we leave it up to the patient to decide how they wish us to help treat their condition, or not.