Knee Pain

Knee pain is a very frequent cause of debilitation. Millions of patients suffer with knee pain that can be caused by a work, exercise, trauma, or even daily activities. The knee joint carries all of the body weight and begins to degenerate. Because of the various impact forces that the knee must sustain, pain may occur even if there is no gross injury. Knee pain will limit basic activities such as walking within the house or at work which will impact activities of daily living. Knee pain will frequently affect a person’s gait which will then need to back pain in many scenarios. The mechanics of walking impact the entire body from the feet all the way up to the cervical spine.

If untreated, patients are not able to engage with exercise. This leads to a sedentary lifestyle which can cause weight gain and a host of other problems related to obesity, diabetes, and cardiovascular conditions. As a result of pain, one will begin withdrawing from social activities as well which has psychological detriment. An article published in BMC Med 2018 Sept 25 showed chronic disease and musculoskeletal conditions have a significant global burden.

The knee joint actually has one of the largest cartilage surfaces in the body. At times the joint can support 2 to 5 times a person’s body weight. Chronic knee pain affects about 25% of Americans. Knee pain can occur along the entire joint from front to back or side to side. Patients may describe sharp or dull ache that worsens with movement. Walking commonly aggravates the symptoms especially for a prolonged period of time. Standing may cause pressure along the joint line and also create pain followed by swelling. Sports and knee injuries will commonly have pain along with swelling and heat at the joint.

Knee pain can occur in the setting of acute trauma, spontaneous swelling, or referred pain that is a result of another body part. Pain that occurs after injury is concerning for possible structural damage of ligaments, cartilage, tendons, or soft tissue tears. If patients can identify the timing of a specific event that most likely trauma has occurred.

Specific activity such as a new training exercise program or repetitive motions can also help identify specific causes. Specific shoes, braces, or training volume that is introduced to a patient’s lifestyle at times is responsible for treating the pain. When patients present to medical care, pinpointing the exact location can sometimes diagnose whether a specific tendon, ligament, bone is at play. Systemic causes such as rheumatology and infection diseases can attack joints as well.

Swelling in the knee may be a result of traumatic or nontraumatic causes. If swelling occurs in a rapidly progressing phase it may signal trauma that occurs with bleeding into the knee joint such as an anterior cruciate ligament tear (ACL tear or torn ACL). If there is no trauma but swelling occurs, this usually suggests a systemic disease such as rheumatologic, infectious, or gout. In this case aspiration and diagnosis of the fluid would be indicated for further testing. Swelling in the knee joint can be assessed using ultrasound from the ACL tear (torn ACL). Moderate or large volumes of swelling that is more than 4 teaspoons can be detected on physical examination. However smaller effusions would require ultrasound. The presence of swelling in the knee suggests acute trauma or damage to the bone, cartilage, ligament.

Prior knee surgery is one of the most strongly correlated risk factors for future knee pain. The history of previous surgical injury and stability sometimes can help the physician point to the current diagnostic dilemma. Often times knee pain is a complication of an old or recurrent injury. For example, patients with patellofemoral pain can be attributed to a different gait. Walking or running can cause chronic Achilles tendinopathy. Sometimes surgical scars leading to a recurrence of the old problem. All patients with prior injury experience some degree of sedentary activity. They become deconditioned and thus predisposes them to new injuries and knee pain.

Common causes of knee pain include patella tendon tear, patella dislocation, anterior cruciate ligament tear, collateral ligament tear, bone defect, cartilage damage. Less common causes include posterior cruciate ligament tear, patella fracture, quadriceps tendon tear.

MRI is useful to diagnosis cartilage problems that occur in the knee related to mild trauma or chronic overuse. A physician would need to evaluate the patient’s condition before ordering such a scan.

Meniscus tear (Meniscal tear).
Certain conditions cause pain that will localize to the front of the joint. For example, a torn meniscus causes pain on both sides of the knee. The meniscus is a soft cartilage pad that absorbs force from the femur. It prevents the femur from grinding on the tibia. Over time this pad will become thinner and susceptible to damage such as crack or tear. Initial injury is accompanied by swelling. The meniscus absorbs forces from walking, running, squatting. Many times, MRI will show a meniscal tear that does not cause pain. However, if there is pain, the symptoms can be diffuse and associated with certain activity such as inability to extend the knee straight. Swelling or pain on squatting also is very common. The physical exam is important to find a positive McMurray test. Medial and lateral meniscal tear can cause pain with this exam which would help the physician in diagnosis.

Arthritis
Arthritis in the knee describes thinning and damage of the cartilage in the joint. It is the leading cause of pain and disability globally and usually presents with diffuse knee pain. It may occur with or without swelling and has a vague timeline. The joint exam for arthritis in knee reveals normal ligament and meniscus testing. Risk factors for arthritis include obesity, greater than 50 years old, prior knee surgery or injury. X-rays or MRIs does not correlate with a patient’s pain. The cartilage that covers the femur and tibia serves to glide the joint when bending the knee. As the cartilage begins to wear down inflammation sets in which causes swelling and pain in the entire knee. Back of knee pain can arise from arthritis.

Bursitis
Bursitis can occur because there are many bursa located around the knee joint. A bursa is a fluid-filled sac that lies between tendons, bones, and skin. The sac is mobile and helps prevent friction between surfaces when rubbing against each other. In the knee, there are prepatellar and infrapatellar bursitis. Sometimes the bursa will become inflamed because of repetitive activities such as kneeling. Ultrasound is useful in assessing swelling of the bursa if there is increased fluid.

Pes Anserine bursitis.
This bursa is particularly common as a source of the knee pain. This bursa is located in the front of middle bottom half of the knee. It is important for preventing injury where tendons attached such as the sartorius, semitendinosus, and gracilus muscles. Pain from this bursa is usually slow in onset and occurs with running or going up the stairs. Focal swelling can occur but not always present.

Quadriceps and patellar tendinopathy are also common causes of pain because many muscles pull on this tendon. This will result in a sprained knee. This tendon is important for jumping, running, squatting. Explosive activity such as sprinting make this tendon a focal point of being pressure.

Plica syndrome. The plica is multiple fibrous tissues that surround the patella and stabilizes the front of the knee. Sometimes because of repetitive activity or trauma tenderness occurs along the inside of the patella.

Chronic patellar dislocation is an increased risk factor for chronic pain. This would require extensive rehabilitation and strengthening of the muscles surrounding the joint.

Patellofemoral pain is frequently encountered because of overuse and usually causes pain in the front of the knee. It is made worse with weightbearing or flexing the knee such as running, squatting, sitting. Patient’s feel their knee “gives out”. Ultrasound may help make sure that another cause such as surrounding ligaments are not injured.

Chondromalacia patella is seen on x-ray which shows softening or erosion on the underside of the patella bone. Patients may note swelling and pain with movement of the front of the knee. An MRI would be important to confirm the diagnosis.

Patellar stress fracture means a portion of the patella bone is involved in knee injuries. This is seen in very active athletes who engage in explosive jumping activities. The timing of this usually occurs when an athlete begins intensive training for several weeks. This signals a high risk of chronic fracture and injury and requires physician consult. MRI is needed to confirm the diagnosis.

IT band (Iliotibial band syndrome).
IT band knee injuries typically cause pain along the side of the knee. It is a thick fibrous band that starts from the thigh and inserts into the outside of the knee. Patient’s typically state there is burning or tenderness across the side of the leg as well. Athletes such as runners or cyclist may experience this more commonly. Ultrasound exam can be helpful to find swelling in the band.

Baker’s cyst.
This cyst is in the back of the knee and causes pain and swelling. Usually there is swelling and fluid around the joint that is contained in the cyst. General activities such as walking or exercise increase this pain region. Ultrasound will usually identify a fluid filled sack. Back of knee pain can occur in this condition.

Popliteus tendon.
Popliteus tendinopathy occurs in the back of the knee. The tendon attaches to the femur and is associated with pain for patients who do downhill walking or running. A sprained knee in this condition will cause back of knee pain.

Ligament injury in the knee can cause instability or clicking sensations when bending. The anterior cruciate ligament and posterior cruciate ligament both serve to keep the femur stable and the knee joint from dislocating. Pain in this region is variable and most patients feel a sense of slipping. Patient may suffer an ACL tear (torn ACL).

Timing of the pain is important. Usually the pain is divided between acute and chronic. Acute knee pain is usually related to direct trauma or specific instance. It is usually abrupt and typically under 6 weeks. Chronic knee pain is usually associated with overuse knee injuries and repetitive activity that lasts more than 6 or 8 weeks. The onset may be insidious. Some patients may experience acute on top of chronic pain suggesting an old injury has been exacerbated.

Traumatic events such as a direct blow to the knee or motor vehicle crash is important to assess because it may help with diagnosis. Non-traumatic events such as jumping, squatting, standing would suggest more of a chronic nature.

The physical exam is particularly important when diagnosing the pain because of the proximity and complexity of structures within one joint. Stressing and doing the appropriate maneuvers based on the potential diagnosis is a skill that a specialist would know. Pain elicited during the examination that is different than usual symptom may be an unrelated diagnosis.

Treatment options for knee pain is best achieved through a combination of injection in conjunction with graded rehabilitative exercise. Individual programs may include cortisone shot, regenerative medicine, PRP injection, PRP treatment or stem cell therapy which boosts the body’s natural ability to heal. After treatment, the patient will go through phases of recovery and ultimately return to daily activities in a matter of days or weeks.

If you experience knee pain, it is important to please contact us as soon as possible to diagnose the problem so that proper treatment can speed up your recovery.