Medicines & Safety
Paracetamol: How Much Is Safe, and the Liver Risk
The safe adult maximum is 4 g in 24 hours. Above that it damages the liver, and for the first day or two an overdose causes almost no symptoms at all.
28 Aug 202611 min read
Osteoarthritis
Also known as OA, Degenerative joint disease, Wear-and-tear arthritis
Osteoarthritis is the gradual loss of the smooth cartilage that lines a joint, leaving stiffness and pain that is worse with use. It is the most common form of arthritis and usually affects knees, hips, hands and the spine.
In Orthopedics
Cartilage is the low-friction surface that lets bone move against bone. In osteoarthritis it thins and roughens, the bone underneath thickens in response, and small bony outgrowths form at the joint margins. The result is a joint that hurts more the more it is used and eases with rest — the reverse of the pattern seen in .
| Osteoarthritis | Rheumatoid arthritis | |
|---|---|---|
| Stiffness in the morning | Brief, under 30 minutes | Prolonged, often over an hour |
| Pattern | Often one-sided, weight-bearing joints | Symmetrical, small joints of hands and feet |
| Pain and activity | Worse with use, better with rest | Better with gentle movement |
| Whole-body symptoms | Not a feature | Fatigue, sometimes fever |
Despite the older name, it is not simply wear from overuse. Age, previous joint injury, genetics and joint shape all contribute, and body weight matters a great deal at the knee — which is why weight, where it is raised, is one of the few things that changes the course of the disease rather than only the symptoms.
Muscle strength around a joint protects it, so exercise is treatment rather than something to be avoided. Painkillers, including an , manage symptoms; joint replacement is considered when pain and loss of function are no longer controlled.
Where this comes up
Orthopedics
Knee Osteoarthritis: Why It Hurts and What Genuinely Helps
Worn knee cartilage is common after 45 and rarely means surgery is coming. Exercise and weight carry more evidence than any tablet, injection or supplement.
11 Aug 202610 min read
Related terms
- ArthritisJoint inflammation, Joron ka dardArthritis means pain, swelling and stiffness in a joint. It is an umbrella word covering more than a hundred conditions, of which wear-related osteoarthritis and immune-driven rheumatoid arthritis are the two commonest.
- Rheumatoid arthritisRARheumatoid arthritis is an autoimmune disease in which the immune system attacks the lining of the joints, causing pain, swelling and prolonged morning stiffness. Untreated it damages joints permanently, so early treatment matters.
- InflammationSwelling, SozishInflammation is the body's response to injury or infection: blood flow increases, fluid and immune cells arrive, and the area becomes red, warm, swollen and painful. It is a repair process, and it becomes a problem only when it persists.
- NSAIDNon-steroidal anti-inflammatory drug, Anti-inflammatory painkillerNSAIDs are painkillers that also reduce inflammation and fever — ibuprofen, diclofenac, naproxen and aspirin among them. They work well but carry real risks to the stomach, the kidneys and the heart.
- BMIBody mass index, Quetelet indexBody mass index is weight in kilograms divided by height in metres squared, used as a rough screen for whether a person carries too much or too little weight for their frame. South Asians face weight-related risk at a lower BMI than the standard chart assumes.
- OsteoporosisBrittle bone disease, Thin bonesOsteoporosis is loss of bone density that leaves bones fragile enough to break from a minor fall or even a cough. It causes no symptoms until a fracture happens, which is what makes it dangerous.