Knee Osteoarthritis
What is Knee Osteoarthritis?
Knee osteoarthritis (OA) is a degenerative joint condition that results from the gradual breakdown of cartilage in the knee joint. The knee is a hinge joint where the femur (thigh bone), tibia (shin bone), and patella (kneecap) come together. A layer of smooth cartilage covers these joint surfaces, enabling frictionless movement and shock absorption.
With OA, this protective cartilage deteriorates over time, leading to increased friction between the bones, pain, stiffness, and swelling. As the condition progresses, bone spurs may develop, further contributing to discomfort and limited mobility.
Causes of Knee Osteoarthritis
There is no single cause of knee osteoarthritis, but several factors can contribute to its development, including:
- Aging: Cartilage naturally wears down over time, increasing the risk of OA with age.
- Genetics: A family history of osteoarthritis may predispose individuals to the condition.
- Previous knee injuries: Fractures, ligament injuries, or meniscus tears can accelerate joint degeneration.
- Obesity: Excess body weight places additional stress on the knee joint, accelerating cartilage breakdown.
- Repetitive stress: Jobs or activities that involve frequent kneeling, squatting, or heavy lifting can increase the risk.
- Joint malalignment: Abnormal knee alignment (such as bowlegs or knock-knees) can lead to uneven wear on the joint.
Symptoms of Knee Osteoarthritis
Symptoms of knee OA may develop gradually and worsen over time. Common signs include:
- Knee pain: Discomfort that worsens with activity and improves with rest. Pain may be localized to the front, sides, or back of the knee.
- Stiffness: Difficulty moving the knee, especially after periods of inactivity, such as upon waking in the morning.
- Swelling: Inflammation in the knee joint, which may cause visible swelling or warmth.
- Crepitus: A cracking, grinding, or popping sensation when bending or straightening the knee.
- Weakness or instability: The knee may feel weak or give way during movement due to muscle imbalances or joint instability.
Diagnosis of Knee Osteoarthritis
To diagnose knee osteoarthritis, a healthcare professional will:
- Review medical history: Discuss symptoms, lifestyle factors, and any past knee injuries.
- Perform a physical examination: Assess knee movement, joint stability, and signs of inflammation.
- Order imaging tests: X-rays help identify cartilage loss, bone spurs, and joint space narrowing. In some cases, an MRI may be used to assess soft tissue damage.
Non-Surgical Treatment Options
Many individuals manage knee OA effectively with non-surgical interventions, including:
- Activity modification: Avoiding activities that worsen symptoms while maintaining a healthy level of movement.
- Weight management: Losing excess weight to reduce stress on the knee joint.
- Physical therapy: Strengthening exercises for the quadriceps, hamstrings, and hip muscles to support the knee.
- Pain management: Over-the-counter or prescription nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, can help reduce pain and inflammation.
- Joint injections: Corticosteroid injections provide temporary relief by reducing inflammation, while hyaluronic acid injections may improve joint lubrication.
- Bracing or assistive devices: Knee braces or walking aids, such as canes, can provide additional support and alleviate stress on the knee.
Surgical Treatment for Knee Osteoarthritis
If conservative treatments are ineffective, surgical options may be considered, including:
Arthroscopic Surgery
A minimally invasive procedure where a surgeon removes loose cartilage fragments or smooths damaged areas within the knee joint. This option is generally recommended for mild cases of OA.
Osteotomy
This procedure involves reshaping the bones around the knee to redistribute weight away from the damaged area. It is typically considered for younger patients with localized arthritis.
Partial or Total Knee Replacement
- Partial knee replacement: If OA is confined to one part of the knee, only the damaged section is replaced with an artificial implant.
- Total knee replacement: A more advanced procedure where the entire knee joint is replaced with prosthetic components to restore function and relieve pain.
Prevention and Long-Term Outlook
While knee osteoarthritis cannot always be prevented, certain strategies may reduce the risk or slow its progression:
- Maintain a healthy weight: Reducing excess weight lessens stress on the knee joint.
- Stay active: Engaging in low-impact exercises such as swimming, cycling, or walking can help maintain joint health and muscle strength.
- Practice proper joint care: Avoiding repetitive stress on the knees and using supportive footwear can help protect the joints.
- Early intervention: Seeking medical advice at the onset of symptoms can lead to better long-term outcomes and prevent further joint damage.
With early treatment and appropriate lifestyle modifications, many individuals with knee osteoarthritis can effectively manage symptoms and maintain mobility. For those with severe OA, surgical interventions can provide significant pain relief and improved quality of life. If you experience persistent knee pain or stiffness, consult a healthcare professional to determine the best course of action for your condition.
Further information
Last updated29 Apr 2025