Knee Osteoarthritis
What is the Function of Cartilage in the Knee?
The knee joint is covered by articular cartilage, a smooth, durable tissue that lines the ends of the femur (thigh bone), tibia (shin bone), and the underside of the patella (kneecap).
Cartilage serves several essential functions to reduce friction between bones, allowing smooth movement.
Healthy cartilage ensures pain-free motion and even weight distribution through the knee during walking, running, and other daily activities.
How Does Knee Arthritis Occur?
Knee osteoarthritis is a degenerative joint disease in which the protective cartilage gradually breaks down. As the cartilage wears away:
The joint space narrows.
The bones begin to rub against each other, causing pain and inflammation.
The bone reacts to the lack of cartilage by forming bony spurs (osteophytes).
The soft tissue around the knee thickens and the joint becomes stiff.
In advanced arthritic conditions, the bone can start to wear away, creating a deformity.
This process typically develops over years and is influenced by several factors, including:
Age-related wear.
Previous injury or surgery (e.g., ACL tear, meniscus removal).
Genetic predisposition.
Obesity, which increases load on the knee joint.
Malalignment (bow-legged or knock-kneed deformity).
Over time, the combination of cartilage loss, inflammation, and altered mechanics leads to pain, stiffness, and functional limitation.
How Do You Diagnose Knee Arthritis?
Diagnosis is based on clinical history, examination, and imaging findings.
Clinical Assessment:
Pain: Often felt along the joint line or behind the kneecap, worse with activity and relieved by rest.
Stiffness that gradually worsens over time.
Swelling: Caused by inflammation or fluid accumulation (effusion).
Grinding or clicking: From rough joint surfaces.
Imaging:
X-rays are the main diagnostic tool and typically show:
Narrowed joint space.
Bone spurs (osteophytes).
Subchondral sclerosis (thickening of bone).
Joint deformity in advanced stages.
MRI may be used in selected cases to evaluate the quality of cartilage in other compartments of the knee.
CT scan may be used for preoperative planning.
What are the Long-Term Consequences of Knee Arthritis?
Knee osteoarthritis is a progressive disease that cannot be reversed with current medical treatments. The long-term consequences of knee arthritis are:
Gradual worsening of knee pain and swelling.
Loss of mobility and increased stiffness.
Reduction in walking distance.
Muscle weakness due to reduced activity.
Progressive deformity (bow-legged or knock-kneed alignment).
Gradual reduction of quality of life, sleep disturbance, and potentially difficulty with work or recreational activities.
What are the Indications for Conservative Management of Knee Arthritis?
Most patients with mild to moderate osteoarthritis benefit from non-surgical (conservative) management.
Indications include:
Early or moderate disease with preserved joint space.
Pain is manageable with medication and activity modification.
No significant deformity or mechanical instability.
Patients preferring to avoid or delay surgery.
The medical risk of surgery is significantly more than the benefit.
Conservative treatment may include:
Activity modification: Avoid high-impact activities (running, jumping).
Physiotherapy: Focused on strengthening the quadriceps, hip, and core.
Weight management: Reduces load on the knee and slows progression.
Anti-inflammatory medications for pain and swelling.
Knee bracing or supportive footwear to offload affected areas.
Injections, such as corticosteroid, hyaluronic acid or PRP injections.
These measures often improve symptoms, particularly in early disease, but they do not stop the progression of arthritic changes in the knee.
What are the Indications for Surgical Management of Knee Arthritis?
Surgery may be recommended when conservative treatment no longer provides adequate relief or when joint damage is advanced.
Indications include:
Severe pain and stiffness affecting sleep or daily activities.
Failure of non-operative management after several months.
Advanced arthritis with significant cartilage loss and joint space narrowing on imaging.
Surgical options include:
Osteotomy – a realignment procedure for younger patients with arthritis affecting one side of the knee.
Partial (unicompartmental) knee replacement – for arthritis confined to one part of the knee.
Total knee replacement (arthroplasty) – for advanced arthritis affecting multiple compartments.
Surgical management aims to relieve pain, correct deformity, and restore mobility and quality of life. There is a limited role of arthroscopy (key-hole surgery) in the management of osteoarthritis of the knee.
