How Does Osteoarthritis Affect the Knees?

Osteoarthritis (OA) is a common joint disorder that affects millions of people worldwide. Understanding how osteoarthritis impacts the knees is essential for better management and treatment of the condition. This article will delve into the specifics and complexities of knee osteoarthritis, its various causes, key symptoms, diagnosis process, and treatment options, providing a comprehensive guide to identifying, treating, and managing this difficult condition.

What is Osteoarthritis?

Osteoarthritis is a degenerative joint disease characterized by the breakdown of cartilage, the protective tissue found at the ends of bones. This breakdown leads to the development of pain, swelling, and reduced mobility in the affected joint. Osteoarthritis can affect any joint in the body but is particularly prevalent in the weight-bearing joints like the knees.

Causes and Risk Factors

Osteoarthritis is a complex condition with many possible contributing factors. A better understanding of these causes and risk factors can help individuals like yourself take proactive steps to best manage and potentially reduce their risk of developing knee osteoarthritis.

1. Age

The risk of osteoarthritis increases with age. As we age, the cartilage that cushions the ends of our bones naturally wears down. This process, known as degeneration, is a part of the normal aging process. However, over time, the ability of cartilage to repair itself diminishes, which leads to the gradual breakdown of the cartilage. Consequently, older adults are more susceptible to osteoarthritis, particularly in weight-bearing joints such as the knees.

2. Genetics

A family history of osteoarthritis can also increase the likelihood of developing the condition. Genetics plays a significant role in the development of osteoarthritis. If your parents or siblings have osteoarthritis, your chances of developing it are higher than average. Specific genetic variations can also affect the body’s ability to maintain healthy cartilage, speeding up the process of osteoarthritis developing.

3. Obesity

Excess body weight stresses the knee joints, accelerating cartilage breakdown. Obesity is one of the most significant modifiable risk factors for knee osteoarthritis. As the knees bear much of the body’s weight, each extra pound of body weight adds about four pounds of pressure on the knee joints. This increased stress accelerates the wear and tear of the cartilage, leading to faster degeneration. Additionally, body fat produces inflammatory cytokines that can further contribute to joint degeneration.

4. Joint Injuries

Previous knee injuries can also predispose the joint to osteoarthritis. Acute injuries such as fractures, ligament tears, and meniscal injuries can damage the cartilage and alter the joint’s biomechanics. These changes can lead to abnormal or increased stress on the knee joint, accelerating cartilage wear and increasing the risk of osteoarthritis.

5. Repetitive Stress on the Joints

Occupations or regularly performed activities that involve repetitive knee movements or periods of prolonged knee stress can lead to joint degeneration. Actions such as frequent kneeling, squatting, heavy lifting, or repetitive motion can put excessive stress on the knee joints. Over time, this repetitive stress can cause micro-damage to the cartilage, leading to its gradual breakdown and the development of osteoarthritis. Individuals in certain professions, such as construction workers, athletes, and farmers, are at higher risk due to the physical demands and nature of their work.

6. Other Medical Records

Conditions such as rheumatoid arthritis can increase the risk of developing osteoarthritis. Other forms of arthritis, particularly inflammatory types like rheumatoid arthritis, can predispose individuals to osteoarthritis. Chronic inflammation from these conditions can damage the cartilage and surrounding tissues, accelerating the degenerative process. Additionally, many metabolic disorders, such as diabetes and conditions like gout, can also contribute to the development of osteoarthritis by causing inflammation or impaired cartilage repair.

7. Other Factors

While the above factors are the most prominent, several other elements can influence the risk of knee osteoarthritis:


Women are more likely to develop osteoarthritis than men, particularly after menopause, suggesting hormonal influences play a role.

Bone Density

Individuals with lower bone density may be at higher risk for osteoarthritis.

Muscle Weakness

Weak muscles around the knee can lead to instability and increased wear on the joint, contributing to osteoarthritis development.

Joint Alignment

Abnormal joint alignments, such as knock-knees or bowlegs, can create uneven stress on the knee joint, leading to increased wear and tear.



Understanding these causes and risk factors highlights the importance of maintaining a healthy lifestyle, managing body weight, protecting joints from injury, and addressing underlying medical conditions to help reduce the risk of developing knee osteoarthritis. If you are at risk or experiencing symptoms, early consultation with a healthcare professional can help.

Anatomy of the Knee Joint

Understanding the knee’s anatomy is important to be able to visualize how exactly osteoarthritis affects it. The knee is a complex structure consisting of bones, cartilage, synovial membrane, ligaments, and tendons. Let’s break it down.


The knee joint consists of three bones:


Femur (thighbone): The upper part of the knee.

Tibia (shinbone): The lower part of the knee.

Patella (kneecap): Protects the knee joint and improves muscle leverage.


Cartilage is a smooth, rubbery tissue covering the ends of the bones. It includes:


Articular Cartilage: Covers the ends of the femur, tibia, and patella, allowing smooth movement.


Meniscus: Two crescent-shaped pieces (medial and lateral) that act as shock absorbers.

Synovial Membrane

The synovial membrane lines the joint capsule, producing synovial fluid that lubricates the joint and reduces friction.

Ligaments and Tendons

Ligaments and tendons provide stability and facilitate movement:


Ligaments: Connect bones to bones, including the ACL, PCL, MCL, and LCL, providing joint stability.


Tendons: Connect muscles to bones, such as the quadriceps and patellar tendons, enabling movement.

How a Healthy Knee Functions

A healthy knee joint allows for smooth movement with minimal friction. The cartilage is a cushion, while the synovial fluid lubricates the joint, facilitating painless motion.

In a healthy knee, the following should be true:

Smooth Movement: Articular cartilage allows bones to glide with minimal friction.

Proper Shock Absorption: Menisci distribute weight and reduce impact.

Adequate Lubrication: Synovial fluid reduces wear.

Damage or deterioration in any of these components, as seen in cases of osteoarthritis, compromises the knee’s function, leading to pain, stiffness, and reduced mobility.

How Osteoarthritis Develops in the Knee

Osteoarthritis in the knee is a degenerative process that unfolds over years and through several progressive stages, ultimately leading to joint pain, stiffness, and impaired function. Here’s a detailed look at how this condition develops and unfolds.

Breakdown of Cartilage

As cartilage deteriorates, it loses its ability to cushion the bones, leading to increased friction and joint pain.


Cartilage is a smooth, rubbery tissue that covers the ends of bones in a joint, enabling them to glide smoothly over each other. In osteoarthritis, the cartilage begins to break down and wear away. This degradation can result from a combination of mechanical stress and biochemical changes within the joint. 


As the cartilage thins and deteriorates, it becomes less effective at cushioning the bones, leading to increased friction during movement. This friction causes pain, particularly during weight-bearing activities, and can lead to the characteristic symptoms of osteoarthritis.

Changes in Synovial Fluid and Joint Lining

The synovial fluid becomes less effective at lubricating the joint, and the synovial membrane may become inflamed, contributing to pain and swelling.


The synovial membrane lines the joint capsule and produces synovial fluid, which lubricates the joint and nourishes the cartilage. In osteoarthritis, changes occur in the composition and volume of the synovial fluid, reducing its lubricating efficiency. 


Additionally, the synovial membrane can become inflamed (a condition known as synovitis), leading to further pain and swelling. This inflammation contributes to the degradation of cartilage and exacerbates the symptoms of osteoarthritis.

Changes in the Bone

This includes the formation of bone spurs (osteophytes). The body attempts to repair damaged cartilage by growing new bone in the form of spurs, which are bony projections that develop along the edges of the bones. This can cause additional pain and restrict movement.


While these spurs are intended to stabilize the joint, they often cause further pain and restrict movement by negatively affecting surrounding tissues. Osteophytes can also contribute to joint stiffness and the grinding sensation often felt in advanced osteoarthritis.

Narrowing in the Joint Space

As cartilage wears away, the space between the bones narrows, leading to increased bone-on-bone contact and joint stiffness. This reduction in the space between the bones in the knee joint is a hallmark of osteoarthritis, which can be seen on X-rays. 


This narrowing results in increased bone-on-bone contact, which further accelerates cartilage wear and exacerbates joint pain and stiffness. The reduced joint space also limits the range of motion, making everyday activities like walking, climbing the stairs, and bending the knee more difficult and painful.

Inflammation and Its Role in Osteoarthritis

Inflammation is a key symptom of osteoarthritis, causing pain, swelling, and further deterioration of the joint structures.


Although osteoarthritis is often considered a “wear-and-tear” disease, inflammation also plays a crucial role in its progression. Inflammatory mediators released by the synovial membrane and other joint tissues contribute to the ongoing breakdown of cartilage and the formation of osteophytes. Chronic inflammation can create a cycle of pain and swelling, further damaging the joint structures. This inflammatory process not only affects the cartilage but can also impact the underlying bone, synovial lining, and other soft tissues in the knee.


In summary, osteoarthritis of the knee is a multifaceted condition involving the progressive breakdown of cartilage, changes in synovial fluid, formation of bone spurs, narrowing of the joint space, and chronic inflammation. Hopefully, this highlights the importance of early intervention and thorough management to slow progression and alleviate symptoms.

Symptoms of Knee Osteoarthritis

Individuals with knee osteoarthritis may experience a range of symptoms, including:

Pain and Tenderness

Osteoarthritis can cause persistent pain in the knee, especially after activity or prolonged rest. The pain is often described as a deep, aching sensation, which can become more pronounced after physical activity or at the end of the day. Tenderness around the joint is also common, making it painful to touch or apply pressure to the knee.


Notable stiffness after periods of inactivity, such as in the morning, is a common symptom of osteoarthritis. This stiffness is usually most pronounced after waking up or after sitting for extended periods. The knee may feel “locked” or difficult to move initially, but the stiffness typically improves with gentle movement and time.


Sufferers of osteoarthritis can expect swelling around the knee joint due to inflammation. The knee may appear visibly swollen and feel warm to the touch. Swelling is caused by the buildup of excess fluid in the joint, a response to the ongoing inflammation and cartilage breakdown.

Reduced Range of Motion

Another common symptom is difficulty in fully bending or straightening the knee. As osteoarthritis progresses, the range of motion in the knee can become increasingly limited. This makes activities such as squatting, kneeling, or even walking more challenging.

Clicking or Popping Sounds

Audible sounds during knee movement caused by rough surfaces rubbing together can also be present. These sounds, known as crepitus, occur when the smooth cartilage that normally facilitates quiet, fluid movement deteriorates, causing the bones to rub against each other or against roughened cartilage surfaces.

Weakness or Buckling

The knee may feel weak or give way, increasing the risk of falls. Muscle weakness around the knee, along with joint instability, can cause the knee to buckle or give out, particularly when walking or going up and down stairs. This instability increases the risk of falls and can significantly impact daily activities.

Diagnosis of Knee Osteoarthritis

Healthcare professionals use various methods to diagnose knee osteoarthritis, this includes:

Physical Examination

A thorough physical examination helps identify signs of knee osteoarthritis, such as pain, swelling, and reduced range of motion. During the examination, the doctor will assess the knee’s flexibility, alignment, and strength, as well as check for areas of tenderness, swelling, and crepitus.

Patient History

Doctors will inquire about the patient’s medical history, including any previous knee injuries, symptoms, and family history of osteoarthritis. Understanding the patient’s history helps identify risk factors and other conditions that might contribute to joint pain.

Imaging Tests

X-rays and MRI scans are commonly used to visualize joint damage, cartilage loss, and bone changes. X-rays can show joint space narrowing, bone spurs, and other structural changes, while MRIs provide detailed images of soft tissues, including cartilage and ligaments.

Joint Fluid Analysis

In some cases, analysis of the synovial fluid from the knee joint can help confirm the diagnosis and rule out other conditions. This procedure involves extracting a small amount of fluid from the joint with a needle. The fluid is then examined for signs of inflammation, infection, or crystals, which can indicate conditions like gout or rheumatoid arthritis.

The Impact of Knee Osteoarthritis on Daily Life

Knee osteoarthritis can significantly affect daily life in several ways:

Difficulty in Performing Every Day Activities

Activities such as walking, climbing stairs, and kneeling become challenging and painful. The pain and stiffness associated with osteoarthritis can make simple tasks, like getting out of a chair or taking a walk, difficult and exhausting.

Impact on Physical Activity and Exercise

Pain and stiffness may limit the ability to engage in physical activities and exercise, leading to a more sedentary lifestyle. However, this reduced activity can then lead to further muscle weakening, exacerbating joint instability and increasing the risk of weight gain and other health problems.

Psychological Effects

Chronic pain and reduced mobility can lead to frustration, anxiety, and depression. The ongoing struggle with pain and functional limitations can take a toll on mental health, reducing overall quality of life and well-being. For those with osteoarthritis, support from friends, family, and one’s community can be incredibly helpful in maintaining good mental health.

Economic Burden

Managing chronic knee pain and treatment costs can place a financial strain on individuals and families. The constant need for medications, physical therapy, assistive devices, and potentially surgery can result in significant out-of-pocket expenses and lost workdays.

Treatment Options for Knee Osteoarthritis

There are various treatment options available to manage knee osteoarthritis:

Non Surgical Treatments

There are a few steps one can take before the need for surgery, including;


Pain relievers and anti-inflammatory drugs can help manage symptoms by reducing pain and inflammation. However, this is not a permanent fix and only improves the patient’s immediate symptoms.

Physical Therapy and Exercise

Regular exercise and physical therapy can strengthen the muscles around the knee, improve flexibility, and reduce pain. Specific exercises can help maintain joint function and prevent further degeneration.

Weight Management

Maintaining a healthy weight reduces stress on the knees, alleviating pain and slowing the progression of osteoarthritis.

Knee Braces and Supports

Braces like the Ascender Knee Brace can provide additional support, stabilize the knee joint, and alleviate pain. They enhance mobility and function, leading to a more active lifestyle regardless of one’s condition.


Corticosteroid or hyaluronic acid injections can reduce inflammation and provide temporary relief from pain and swelling.

Surgical Options

When other treatments are unsuccessful, surgery may be necessary. Here are the various pathways that one may take in this regard.


A minimally invasive procedure to remove damaged cartilage or repair the joint. This option is generally used for younger patients or those with specific types of cartilage damage.


Realigning the bones to relieve pressure on the knee joint. This procedure can help shift weight away from the damaged part of the knee.

Partial or Total Knee Replacement

In severe cases of osteoarthritis, replacing the damaged joint with an artificial one is considered. This surgery is considered when other treatments have failed to relieve pain and improve function.

Management and Prevention

Adopting certain lifestyle changes can help manage knee osteoarthritis effectively:

Exercises and Stretches

Regular exercises and stretches improve knee strength and flexibility. Low-impact activities such as swimming, cycling, and yoga can enhance joint function and reduce pain.

Assistive Devices

Using assistive devices such as canes or walkers can provide additional support and improve mobility. These devices help reduce the load on the affected knee, making movement easier and safer.

Pain Management Techniques

Techniques like hot and cold therapy and acupuncture can help manage pain. Heat therapy can relax muscles and improve circulation, while cold therapy can reduce inflammation and numb pain. Acupuncture has also been shown to provide pain relief in some individuals.

Using a Knee Brace

Knee braces, such as the Ascender Knee Brace, can provide significant relief by properly stabilizing the knee joint, reducing pain, and enhancing one’s overall mobility. They are particularly useful for individuals with moderate to severe osteoarthritis, offering support during daily activities and exercise. Thanks to 3D scanning technology, the Ascender is also able to be custom-made to order, ensuring an excellent fit.

Osteoarthritis and the Knees

Knee osteoarthritis is a common and often debilitating condition that affects millions of people worldwide. Understanding its symptoms, causes, and range of treatment options is crucial for managing this condition effectively. 

Early diagnosis and a comprehensive management plan, including lifestyle changes and the use of supportive devices like the Ascender Knee Brace, can significantly improve the quality of life for those suffering from knee osteoarthritis. 

If you suspect you have knee osteoarthritis, consult with a healthcare professional to develop a personalized treatment plan. For those looking for supportive solutions to treat their osteoarthritis, don’t hesitate to contact one of our representatives.

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