Have Back of the Knee Pain? Learn About Potential Causes and Treatment

Through routine use, we apply substantial pressure to the knees everyday. Without the proper care and preventative measures, constant pressure can result in significant knee pain.

For some context, the knee is a joint consisting of the tibia (shinbone), femur (thighbone), and the patella (kneecap). The joint arrangement allows for forward and backward movement, with cartilage structures called menisci acting as shock absorbers and providing stability (1). Additional muscles, ligaments, and soft tissue around the knee also act as stabilizers (2).

Torn Meniscus

Meniscal tears account for a majority of knee injuries.

Each knee has two menisci: the U-shaped medial meniscus, located on the inside of the knee, and the S-shaped lateral meniscus, on the outside of the knee.

Tears form when the knee forcefully twists or turns. They can also result from lower-impact movement, such as movement from kneeling, squatting, or lifting heavy objects. Meniscal tears affect people of all ages, including those who play intense sports like soccer or rugby, as well the elderly, whose ligaments have grown weak over time (1, 3).

Injuries can often be identified by an audible “pop” at the time of the accident, usually followed by swelling (3).‍

Arthritis

Posterior knee pain can also develop from arthritis.

The two forms of arthritis most likely to cause knee pain are osteoarthritis (OA), which gradually wears down the joint cartilage, and rheumatoid arthritis (RA), an autoimmune disease in which the body mistakenly attacks the joints, are most likely to cause posterior knee pain (4, 5, 6).

Intense pain that worsens with movement may indicate knee OA. This condition disproportionately affects men over 60 (7).

On the other hand, knee swelling, redness, and warmth may indicate knee RA. It’s symmetrical and typically affects both sets of joints, so it’s likely that both knees will be affected. Knee RA varies in severity and may repeatedly disappear and reappear (8).‍

Overuse

Athletes and people who exercise regularly may develop overuse injuries.

Jumper’s Knee, or patellar tendonitis, is characterized by small tears in the tendon which connects the kneecap to the shinbone. It worsens over time and usually affects those who play sports involving jumping (hence the name) like volleyball and basketball. Studies show it’s more common in men than women (9).

Jumper’s Knee causes intense pain, swelling, and tearing or popping sensations. The knee can buckle randomly, making walking difficult (10).

Runner’s Knee, known as Patellofemoral Pain Syndrome, manifests as mild discomfort around the front of the kneecap. It’s usually seen in young, active individuals (11).

Strenuous exercise like running and rock climbing can lead to Runner’s Knee. Other possible causes include tight hamstrings, poor foot support, and weak thighs. This condition can signal a structural defect or incorrect running form (12).

Runner’s Knee usually worsens during movement or during long periods of inactivity. Some people with this condition also experience chondromalacia patella, a breakdown of the cartilage on the underside of the kneecap (12, 13).

Gastrocnemius tendonitis is a calf muscle injury. The gastrocnemius, a posterior muscle that makes up half of the calf, is at a particularly high risk for strains because it crosses both the knee joint and the ankle joint (14).

This condition was first encountered in tennis players and as such is often called ‘tennis leg’ (15).

Biceps femoris tendonitis is a hamstring strain resulting from the inflammation of the biceps femoris muscle, on the outer part of the posterior thigh. It’s more likely to affect people who swim, bike, or run, due to the type of strains that these activities apply to the legs and knees. Older age is a risk factor (16, 17).

Signs of this condition include swelling in the knees or thighs, knee pain that extends up to the thigh and hip, and trouble with bending the knee. Pain increases with movement (17).‍

Ligament Injury

‍Ligament damage can significantly limit knee movement.

ACL tears make up 64 percent of all athletic knee injuries in sports like football and basketball. A direct hit to the knee by an object or a person, or a sudden change in speed or direction while running, can directly cause a tear in the ACL. A pop might sound at the time of injury, which is followed by pain and swelling (18, 19, 20).‍

PCL injuries are less common and occur with sudden, direct impacts to the knee. Swelling, stiffness, and posterior knee pain may indicate a PCL tear (19, 20).‍

Baker’s Cyst

A Baker’s cyst, or popliteal cyst, is a swollen mass at the back of the knee. The cyst itself isn’t harmful, but it does usually indicate an underlying problem, such as arthritis or a cartilage tear. Treating the original source of inflammation should eliminate the cyst (21, 22).

Symptoms of a Baker’s cyst include pain and tightness in the knee, especially during physical activity (21, 23).‍

Deep Vein Thrombosis

‍Deep Vein Thrombosis (DVT) is a blood clot that usually appears in the lower leg or thigh. Injury to a vein, a sedentary lifestyle, complications from a course of medication, or a genetic predisposition may cause DVT. Age is a risk factor (24).

If you suspect that you may have DVT, seek help immediately (25).

Infrapatellar bursitis

Infrapatellar bursitis occurs when the synovial bursae, the fluid-filled sacs that cushion the knee, become inflamed. This can result from repetitive kneeling, a knee injury, or an infection.

The primary symptoms are knee pain, tenderness, warmth, and swelling (26).

Mechanical Issues

‍Mobility problems can contribute to posterior knee pain.

Kneecap dislocation can lead to severe patellar pain. Swelling, tenderness, and cracking sounds may accompany the dislocation. The knee may visually appear to be deformed, with the kneecap easily moving from side to side (27).

Iliotibial (IT) band syndrome, common in long-distance runners, is caused by the inflammation of the outer IT band. This condition typically causes sharp pain on the outer part of the knee joint (28).

Loose ligaments or joints could be a cause of posterior knee pain. Injury or wear-and-tear can lead to bone or cartilage breakage, resulting in discomfort (29).

Other Causes

‍A fractured kneecap, though uncommon, can cause intense knee pain. Patellar fractures, which make up only one percent of all skeletal injuries, result from direct trauma to the knee. The knee will appear swollen and bruised (30).

In rare cases, posterior knee pain may indicate a cancerous bone tumor, such as a tumor caused by osteosarcoma. This kind of cancer can affect anyone, including younger people, and is characterized by a tender knee and the presence of a protruding mass. There are only around 900 new cases of osteosarcoma each year (31, 32).

Before treating your knee pain, seek medical advice from a licensed professional. 

Related Issues

Often, your doctor will be able to make a diagnosis just based on your medical history and a short exam.

Be sure to provide your physician with information about any pre-existing medical conditions like arthritis or blot clots, as these can contribute to knee pain.

Describe the circumstances behind your discomfort. When did the pain begin? Did you engage in physical activity? What does the pain feel like? Is it worse in the morning or at night? Where is it located?

Pain more on the inside of the knee may suggest an MCL injury, arthritis, or a medial meniscus tear. Pain more on the outside of the knee may suggest an LCL injury, arthritis, a lateral meniscus tear, or IT band tendonitis (1).‍

Physical Exams

‍A physician will also observe your range of motion through physical examination.

Your doctor will have you sit and will gently move your affected leg, observing how it responds to flexion, extension, and rotation (33).

Your doctor will look for swelling along the hamstring, gastrocnemius, and popliteus. Tenderness indicates muscle or tendon injury, while pain in the popliteus area suggests a Baker’s cyst. They’ll also check for sounds like crunching or grinding, which can signal arthritis (33).

To gauge the severity of an ACL injury, your doctor may perform an anterior drawer test or a Lachman test. The anterior drawer test assesses extension and the Lachman test checks the range of motion of the shinbone and the knee (33).

The McMurray’s test can confirm meniscal tears. Your doctor will gently rotate the lower leg past 90 degrees until there’s a click or you feel sharp pain (34).

Screening and Imaging

Diagnosing meniscal tears, fractures, and ligament injuries may require imaging, in addition to physical exams. If necessary, your doctor will start by ordering an X-ray scan, and may follow by ordering an ultrasound, MRI, or CT scan (20, 35).

The first line of treatment for your knee pain should be rest, along with abstinence from activities that could pressure the affected knee.

RICE

Rest, ice, compression, and elevation can relieve your knee pain caused if the underlying cause is an overuse injury. You should limit your physical activity if this is the case. Apply ice to your knee in 15 to 20-minute increments, several times a day, and use an elastic band to compress the area. Elevate your injured leg to ease tension.

Support

Your doctor may recommend a knee brace to stabilize your joint. There are several kinds of braces and they each offer different kinds of benefits. Functional braces provide protection and support after an injury. Rehabilitative braces limit knee movement during the recovery process. Prophylactic braces can prevent injury during physical activity (36).

If your brace doesn’t fit correctly, it can irritate your skin or cause bruising, so be sure to select a brace that’s comfortable for you (11, 37).

NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce pain and swelling caused by inflammation associated with arthritis, tendonitis, and bursitis. If your pain doesn’t respond to over-the-counter NSAIDs like Advil, your doctor may prescribe stronger NSAIDs, including topicals like diclofenac gel (20, 38).

NSAIDs can increase blood pressure and exacerbate heart conditions. In recent years, the FDA has issued stronger warnings about the increased risk of heart attack and stroke due to oral NSAIDs, so be sure to follow the directions provided by your doctor when taking these medications (39).

Physical therapy

Physical therapy is an important rehabilitation tool for safely strengthening the knee, and is used to treat almost all types of knee pain, including pain from arthritis, Runner’s Knee, ACL tears, and PCL tears.

Your physical therapist will develop an exercise program to bolster knee stabilization and mobility, while making sure not to place undue stress on your knee. 

Injections

Cortisone injections can relieve persistent pain that’s unresponsive to RICE, NSAIDs, and physical therapy. Cortisone is a strong anti-inflammatory, and is used to treat conditions like a Baker’s cyst, ACL tears, bursitis, and osteoarthritis (40, 41, 42).

Possible side-effects include cartilage damage, joint infection, nerve damage, and the thinning of nearby bone, skin, or soft tissues. Risks increase with higher doses and frequent injections (42).

Surgery

Surgery is only performed when non-invasive methods are insufficient. Conditions that may require surgery include severe osteoarthritis, some knee fractures, certain instances of a Baker’s cyst, chronic kneecap dislocation, certain knee infections, and ligament injuries (1).

Although it’s impossible to eliminate the chance of developing knee pain, preventative measures can reduce the likelihood of knee injury (43).

Stretching and strengthening the quads and hamstrings build knee elasticity and increases resistance to injury (43).

Low-impact exercises, such as swimming, cycling, and rowing, place minimal pressure on the knees (43).

Losing weight may play a role in improving knee pain and preventing injury in overweight or obese individuals (43).Protective gear for the knees can limit strain during activities like yoga and wrestling (43).

There are many possible causes of posterior knee pain.

While uncommon, certain cases of knee pain may be the result of serious underlying conditions, so talk to a doctor before selecting a treatment plan for your knee.

Conservative treatment options, including RICE, NSAIDs, and physical therapy, should be your first line of defense. If the pain persists, your doctor may suggest more serious treatment.

Leading a healthy lifestyle and taking some preventative measures can reduce your likelihood of developing knee pain.