An Overview of Arthritis of the Knee Joint

Symptoms, Causes, Diagnosis, and Treatment

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Arthritis of the knee joint is one of the most common causes of knee pain. Different types of arthritis can affect the knee joint, and the treatment varies depending on the specific condition that is causing the symptoms.

Osteoarthritis is the most common type of knee arthritis. It is characterized by progressive wearing away of the cartilage in the joint. As the protective cartilage is worn away, bone is exposed, the knee becomes swollen, and activities become increasingly painful.

Rheumatoid arthritis (RA), an immune system disorder where the body attacks the joints and other tissues, and it can affect the knees.

Symptoms of Knee Arthritis
Verywell / Gary Ferster

Knee Arthritis Symptoms

Depending on the type of arthritis, symptoms tend to gradually progress as your condition worsens, but they may suddenly worsen with minor injury or overuse.

The most common symptoms of knee arthritis include:

Pain with knee arthritis is usually worse after activity, especially with overuse. Stiffness is common after sitting for long periods. 

As knee arthritis worsens, pain becomes more frequent or may become constant with or without activity. 

Causes

Knee arthritis results in loss of cartilage—smooth tissue that acts like a cushion—in the knee joint. There are many risk factors and causes of knee arthritis, including:

  • Being in your late 40s or older: Joints get worn over time
  • Osteoarthritis is more common and severe in women
  • Extra weight adds pressure on the joints and can make joint damage worse
  • Having parents or siblings with osteoarthritis or inflammatory arthritis
  • Having a previous knee injury, such as a torn meniscus, fracture to the bone around the joints, or a ligament tear
  • Previous knee surgery where damaged cartilage was removed
  • Having a job that is physically demanding and/or involves repetitive knee strain
  • Having another joint condition that has caused joint damage, such as RA
  • Problems with subchondral bone, the layer of bone underneath knee cartilage

Diagnosis

No single test can make a definitive diagnosis of knee arthritis, so your doctor will use imaging studies, a comprehensive medical history, physical examination, and laboratory tests to determine the cause of your symptoms.

Many people over age 50 will have signs of wear and tear in their joints that can be seen on X-rays, If there is a concern about a serious cause, your doctor may order magnetic resonance imaging (MRI), which can provide detailed images of bones, ligaments, tendons, and muscles.

Lab work is helpful in diagnosing or excluding certain causes of knee pain, such as inflammatory arthritis. Lab tests may include blood work and knee aspiration, which involves taking fluid from the knee joint and examining it for abnormalities and infection. 

Treatment

Depending on the type of arthritis, the goal of treatment is to provide pain relief, improve joint mobility and strength, control symptoms to the most possible extent, and prevent further damage to the joint.

Treatment for knee arthritis includes lifestyle modifications, medication, and surgery. 

Lifestyle

There are a number of lifestyle changes and techniques that can help you manage knee osteoarthritis. 

These include:

  • Weight loss (if you are overweight): Weight loss tends to reduce the severity of pain associated with knee arthritis. Reducing pressure on the joint may also prevent your condition from worsening.
  • Joint protection: Modify activities to avoid placing stress on your joints, but also be sure to move around and not to sit for long periods. Use mobility aids as needed. Wear comfortable shoes, eat foods that keep bones strong, and use a knee brace for support.
  • Exercise: Regular activity can help you manage knee arthritis. Exercise can improve the strength of your leg muscles so they can better support your knees. Walking is great physical activity, but if that's too painful, try water exercises in a swimming pool.  
  • Physical therapy: Strengthening the muscles around the knee joint may help decrease the burden on the knee. Preventing atrophy of the muscles is an important part of maintaining functional use of the knee.
  • Hot and cold therapy: Alternating application of heating pads and cold packs can help relieve pain and inflammation in affected knee(s).

Medications

Medication for treating knee arthritis may include anti-inflammatory medicines and pain relievers. 

For the treatment of knee arthritis resulting from RA, corticosteroids or disease-modifying anti-rheumatic drugs (DMARDs) may be prescribed to manage inflammation:

  • Anti-inflammatory medications: Some non-steroidal anti-inflammatory drugs (NSAIDs) are available over-the-counter (OTC), such as Advil (ibuprofen) and Aleve (naproxen). If your doctor thinks you need a stronger NSAID, you may be prescribed a COX-2 selective inhibitor such as Celebrex (celecoxib).
  • Other pain relievers: Another OTC medication, Tylenol (acetaminophen) can be used for pain management, but does not help with inflammation. 
  • Knee injections: Corticosteroid injections can quickly reduce inflammation and pain.  Other injections include viscosupplements. These injections contain gel-like substances that can promote lubrication and cushioning, similar to the synovial fluid in healthy joints.
  • DMARDs: DMARDs help preserve joint health by blocking the inflammation that leads to tissue breakdown. 

Surgery

Surgery is typically a last-resort treatment for knee arthritis.  There are different types of procedures. Some repair and preserve bone while others replace knee joints entirely. Types of knee surgery include:

Knee Arthroscopy

Knee arthroscopy is minimally invasive and involves surgical treatment using an arthroscope (an optical device with a tiny camera) inserted in a joint through a small incision. Additional incisions are made, as needed.

The procedure starts with diagnosing the problem, such as misaligned kneecap or torn meniscus. Once the surgeon has made a diagnosis, they will repair the structures with small tools designed for grasping, shaving, cutting, repairing, and anchor stitching. 

Knee Osteotomy

A knee osteotomy involves cutting out a wedge from either the shin bone or thigh bone to realign the knee and offload pressure from the damaged portion of the joint. Doctors recommend this procedure to correct the bowlegged alignment of a knee.

Knee Replacement Surgery

Knee replacement surgery is among the most commonly performed orthopedic surgical procedures.

With a total knee replacement, the damaged cartilage is removed from the entire knee joint and a metal or plastic implant is inserted in its place. This way the bones of the knee joint are smooth so they can flex and bend freely without pain.

Partial knee replacement involves replacement of only one part of the knee.

A Word From Verywell

Knee arthritis is not curable, but it can be managed with treatments that slow down joint damage and reduce the potential for disability. If you think you might have knee arthritis, don’t delay in getting treatment. Work with your doctor and put together a treatment plan. Managing the condition goes a long way in keeping you active and having a good quality of life. 

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Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Academy of Orthopaedic Surgeons. Arthritis of the knee. Updated June, 2014.

  2. Centers for Disease Control and Prevention. Arthritis: Risk factors. Updated March 7, 2019.

  3. Gersing AS, Link TM. Imaging of osteoarthritis in geriatric patientsCurr Radiol Rep. 2016;4(1):4. doi:10.1007/s40134-015-0133-9

  4. Arthritis Foundation. Lab tests for knee diagnosis.

  5. American Academy of Orthopaedic Surgeons. Knee arthroscopy. Updated September, 2016.

  6. American Academy of Orthopaedic Surgeons. Osteotomy of the knee. Updated June 2017.

  7. American Academy of Orthopaedic Surgeons. Total knee replacement. Updated August, 2015.

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