Knee Pain? What is the Most Common Cause?
by B. Rodney Comisar, MD
Knee pain is one of the most common patient complaints seen in the orthopaedist’s office. There are many causes of knee pain, which can vary depending on the age of the patient. Knee arthritis is certainly high on the list of diagnoses when treating knee pain. Knee arthritis is the most common form of arthritis affecting the large joints in our bodies.
Osteoarthritis, or degenerative arthritis (“DJD”), is the most common form of knee arthritis; rheumatoid and other forms of inflammatory conditions are much less common types of arthritis affecting the knee and other joints. Osteoarthritis (OA) is generally cumulative, a result of “wear and tear.” It can be influenced by trauma or previous injury, weight, occupation, and prior surgery. There is also felt to be a genetic component to OA in some patients. Osteoarthritis describes the deterioration of the articular cartilage coating on the end of the bones at the level of the joint. This can be accompanied by bone spur formation and joint deformity.
Knee pain as a result of osteoarthritis typically has a progressive onset, although acute flares do occur – patients are often unaware of the presence of arthritis until x-rays are taken. Arthritis pain can be diffuse in location or may be localized to a particular area in the knee – medial, lateral, or anterior. Activity-related swelling is commonplace, but persistent swelling is seen less frequently. Mechanical symptoms of popping, cracking, grinding, or even catching and locking may be noted with movement due to the uneven joint surfaces. Morning stiffness or stiffness after periods of sitting and inactivity are noted as well.
Patients with knee arthritis may limp and generally have problems with extended periods of standing and walking. “Start-up” pain getting up from a chair or getting out of a car is commonly cited. Activities of daily living are increasingly affected with time. Many patients also complain of night pain disrupting sleep.
When is it time to consult a physician?
Generally, when the patient’s quality of life is sufficiently affected, it is time to consider an evaluation with a health care professional. Typically, the diagnosis is made by taking a detailed history, performing a comprehensive physical exam, and obtaining x-rays. Weightbearing x-rays are critical, as x-rays taken with the patient sitting or lying down underestimate the extent of degenerative changes in the knee and often need to be repeated when seeing an orthopaedist. MRIs are less useful in the setting of OA, as x-rays are the gold standard in making the diagnosis, and are only performed when the diagnosis is in question. Meniscal tears often accompany the degenerative arthritic process but normally are not a significant source of the symptoms; rather the degenerative meniscal tears are more of an incidental finding.
Dr. B. Rodney Comisar is a board certified, fellowship-trained orthopedic surgeon who specializes in sports medicine related injuries. He has a sub-specialty certification in Sports Medicine. Dr. Comisar offers a full spectrum of sports medicine surgery, including arthroscopy and minimally invasive procedures. Dr. Comisar’s special areas of interest include: multi-ligamentous knee injuries/dislocations; ACL injuries/reconstruction; rotator cuff injuries/tears; patellar instability/dislocation; proximal hamstring ruptures; shoulder instability; and shoulder arthritis including total shoulder replacement and reverse total shoulder replacement.