Knee pain is very common, and many people just assume it’s arthritis or something and try to ignore it. However, most cases of knee pain are not due to arthritis and are instead due to other conditions. In fact, proper diagnosis and treatment can easily resolve many of these issues.
The knee is a very complex joint. It connects the femur (the thigh bone) to the tibia (the larger shin bone, on the inside of the lower leg) and the fibula (the smaller shin bone, on the outside of the lower leg). The knee primarily allows the leg to bend, acting as a hinge joint. It also allows for some medial and lateral rotation.
The knee joint itself consists of the patella, a roundish piece of bone attached to the quadriceps muscle on top of the thigh and to the tibia. This structure works to straighten the leg through the action of the quadriceps muscle. The hamstring muscle, on the bottom of the thigh, is attached to the lower leg and acts to bend the knee.
Ligaments also help in stabilizing the knee joint. The medial collateral ligament (MCL) on the inside of the knee and the lateral collateral ligament (LCL) on the outside of the knee stabilizes it during side-to-side motion. The anterior cruciate ligament (ACL) on the front of the knee and the posterior cruciate ligament (PCL) on the back of the knee stabilize it during front-to-back motion.
The knee is lined with a slippery layer of cartilage and is filled with a lubricant, synovial fluid, that allows it to move smoothly without friction. The knee also has four bursal sacs full of synovial fluid that act like ball bearings. They lie between two surfaces and allow the structures to slide over each other. The largest one lies underneath the kneecap, and two smaller ones are located right above and below the kneecap. The fourth bursa is right below the joint, on the inside of the knee.
In addition, the knee also has shock absorbers. The meniscus, made out of cartilage, lies inside the knee joint and primarily acts to absorb shocks.
With all of these complicated structures that can get injured and malfunction, is it any surprise at all that knees frequently hurt?
The Most Common Causes of Chronic Knee Pain
Traumatic injuries to the knee usually prompt a visit to a doctor for diagnosis and treatment. However, chronic pains and aches in the knee are far more common and are often never diagnosed or treated. Common non-arthritic causes of chronic knee pain include:
- Patellofemoral pain syndrome. Sometimes referred to as runner’s knee. This features a dull pain that occurs under the kneecap and around the front of the knee.
- Bursitis. The inflammation of one of the bursa sacs.
- Baker’s knee. A fluid-filled cyst that forms behind the knee and causes stiffness and discomfort.
- Tendinitis. The irritation of the tendons. It causes pain in the front of the knee that gets worse when climbing stairs or walking up hills.
The first step in seeking relief from knee pain is getting a proper diagnosis. This may require taking a history and observing the anatomy of the knee with ultrasound, x-rays, as well as MRI. A physical therapist will need to examine the motion of the knee, determine if the joint has any abnormal laxness or a limited range of motion, and ascertain when and where the pain occurs.
In most cases, surgery is unnecessary, and physical therapy can help treat the condition. The two primary goals of physical therapy are:
- Retrain the patient to use the correct biomechanics to avoid stressing and injuring the knee.
- Strengthening muscles in the thigh, calf, hip, as well as core to support the knee joint and allow for correct biomechanics.
Your physical therapist will devise a personalized plan to allow the injured structures to heal while working toward these two goals. Your plan may involve wearing a brace for a few weeks while performing strengthening and retraining exercises. Some patients may need to refrain from certain activities that aggravate the injury while they perform the prescribed strengthening and retraining exercises.
In most cases, after a few weeks to months of physical therapy, the knee pain can be either completely relieved or at least substantially improved, and the patient can return to their normal activities. In fact, some patients who retired from sports or a beloved activity, such as running or hiking, find that after treatment, they can resume performing this activity.