Patellofemoral arthritis is a form of knee arthritis. It affects the joint where the kneecap meets the thighbone. People with patellofemoral arthritis may experience pain and stiffness in the knee, difficulty walking, and other symptoms that impact their quality of life.

Although there is no cure for patellofemoral arthritis, medications and physical therapy can help. In more severe cases, surgery is an option.

Knee osteoarthritis is the most common joint disorder and a leading cause of pain and disability in adults. Around 14 million people in the United States have symptomatic knee osteoarthritis.

This article looks at patellofemoral arthritis and its symptoms, diagnosis, and treatment.

A diagram of the knee joint showing where patellofemoral arthritis occurs.Share on Pinterest
Medical Illustration by Bailey Mariner

Patellofemoral arthritis is joint inflammation that occurs where the patella, or kneecap, meets the femur, or thighbone.

The patella rests in a groove at the end of the femur. This groove is known as the trochlea. Patellofemoral arthritis occurs when the cartilage that covers the patella and trochlea starts to break down or becomes inflamed. This can happen for several reasons, including wear and tear, injury, or autoimmune disease.

The patella protects the knee joint and helps keep it stable. When the cartilage breaks down, it can cause pain, swelling, and stiffness in the knee joint. It can also affect a person’s ability to walk.

The primary symptom of patellofemoral arthritis is knee pain, often at the front of the knee. A person may experience pain while resting, but pain more often begins with movement. Activities that pressure the kneecap, such as using stairs, kneeling, or getting up from a chair, may also be painful.

Other symptoms in the knee may include:

  • stiffness
  • swelling
  • a creaking or crackling sensation, which is known as crepitus

As the disease advances, the kneecap can catch or become stuck as a person straightens their knee.

There are several types of arthritis. Some, such as osteoarthritis, occur as a result of cartilage wearing down inside the joint. This may be due to overuse, injury, or dysplasia.

Knee dysplasia is when the patella does not fit properly into the trochlea. This increases stress on the cartilage when the knee moves, causing it to wear down.

Individuals with patellofemoral arthritis also often have a history of knee instability, including dislocation, laxity, or malalignment. Some people may have “patella alta,” meaning that the patella sits higher on the knee than it should.

Other risk factors for developing patellofemoral osteoarthritis include:

  • age
  • obesity or overweight
  • previous fracture of the patella
  • previous dislocation of the patella
  • overuse from sports such as running and weight training
  • history of arthritis in other joints

People can also get patellofemoral arthritis as a result of autoimmune forms of arthritis, such as rheumatoid arthritis and psoriatic arthritis. Other autoimmune diseases, such as lupus, can also cause joint inflammation.

To diagnose this condition, a doctor will take a medical history. They will ask about a person’s general health, symptoms, and daily functioning.

They may then perform a physical exam with the knee in various positions to examine the range of motion and assess pain. They will also look for any signs of injury or muscle loss and listen for crepitus.

Depending on these findings, a doctor may order X-rays to evaluate the patellofemoral joint. Radiographs from the front and side allow the doctor to see whether there is any narrowing of the joint space, degeneration of the articular surfaces, or bone spurs. The doctor may also take X-rays while a person is lying down with their knees bent.

Sometimes, a doctor may also order CT or MRI imaging to assess the joint more thoroughly. However, this is usually not necessary in people with known or suspected arthritis.

Doctors treat most cases of patellofemoral arthritis without surgery, but this depends on the individual. Nonsurgical treatment options include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs): These drugs can ease pain and reduce swelling. Examples include aspirin and ibuprofen.
  • Weight loss: If an individual has a high body weight, their doctor may suggest losing weight to reduce the stress on the knees.
  • Cortisone injections: Cortisone is a steroid and a potent anti-inflammatory. Doctors can inject the medication directly into the knee.
  • Viscosupplementation: In this procedure, a doctor injects a substance into the knee to improve the joint fluid. However, the effectiveness of this treatment for arthritis is currently unclear.

Exercise

Regular physical activity is important for overall health, but it can be difficult when a person has knee arthritis. However, the right kind of exercise may help decrease stiffness and strengthen the muscles that support the knee.

It is critical to avoid activities that stress the front of the knee, such as lunges and squats, as well as activities that directly trigger pain. These may include climbing or descending stairs.

Instead of these high impact activities, people may need to switch to low impact activities such as walking or swimming. Water-based exercise is especially useful, as it can take the weight of the body off the joints. If any exercise makes the knee hurt, a person should stop doing it.

Working with a physical therapist can also help. Physical therapists can suggest specific exercises to improve the knees’ range of motion. They may also suggest exercises to strengthen the quadriceps muscles, which can ease pressure on the kneecap when the leg straightens.

If noninvasive methods do not ease a person’s symptoms, there are surgical options, including:

  • Chondroplasty: In this procedure, a surgeon will smooth and trim the rough joint surfaces in the knee. This may help in mild to moderate arthritis cases.
  • Realignment: This involves tightening or releasing the soft tissues to change the position of the kneecap.
  • Cartilage grafting: In younger individuals with small areas of cartilage damage, doctors may suggest grafting healthy cartilage tissue to the existing knee cartilage.
  • Tibial tuberosity transfer: The tibial tuberosity is the bony prominence on the front of the shinbone. Doctors can move this bone to change the angle of pull on the patellar tendon, which may help relieve symptoms.
  • Patellofemoral replacement: In this procedure, the surgeon replaces the damaged cartilage with metal and plastic. It can be a partial or total replacement, depending on the extent of the damage.

Here are some answers to common questions about patellofemoral arthritis.

How painful is patellofemoral arthritis?

The pain from patellofemoral arthritis can vary from person to person. For some, it is a dull ache that gets worse with activity. For others, the pain can be sharp and severe. Because the pain can worsen with time, anyone with knee pain should see a doctor for prompt diagnosis and treatment.

Can patellofemoral arthritis affect young people?

Yes. Patellofemoral arthritis can affect people of any age, but it is more common in older adults.

Juvenile idiopathic arthritis (JIA) is a risk factor for patellofemoral joint arthritis. This form of arthritis affects children under 16 years old. Children with JIA may develop patellofemoral joint arthritis.

Is there a cure for patellofemoral arthritis?

There is no cure for arthritis in general, as no medications can reverse cartilage or bone loss. However, treatment usually eases pain and helps people move more easily in their daily lives.

Treatment outcomes may vary depending on the individual’s health and the type of treatment. People should talk with their doctor about the results they can expect from treatment.

Patellofemoral arthritis is a type of arthritis that affects the knee. It is a degenerative condition that occurs when the kneecap cartilage breaks down or becomes inflamed.

Symptoms include pain, stiffness, and weakness in the knee. The pain may be worse when going up and down stairs or when sitting for long periods.

There is no cure for patellofemoral arthritis, but treatment can help ease pain and improve quality of life. Treatment may involve medications, lifestyle changes, physical therapy, or surgery.