Osteoarthritis

Osteoarthritis is the most common chronic joint disease. It is an active process involving cartilage, bone, the joint lining, ligaments and surrounding muscles, not simply unavoidable wear and tear. Diagnosis is usually clinical, while exercise, weight management and practical support form the foundation of treatment.

What osteoarthritis is Osteoarthritis is the most common form of arthritis and the most common chronic joint disease. It can cause pain, stiffness, reduced movement and difficulty with everyday activities. It develops when tissues within a joint change and repair becomes less effective. The process usually evolves gradually, although symptoms can vary over shorter periods. Osteoarthritis can affect one joint or several joints. Common sites include the knees, hips, hands, big toes and joints within the neck or lower back. The condition is sometimes described as degenerative because joint tissues change over time. Degenerative does not mean that decline is inevitable or untreatable. Many people improve their pain and function through exercise, weight management, appropriate medicines and practical adaptations. Some eventually benefit from joint replacement surgery. It is not simply wear and tear The phrase wear and tear suggests that a joint behaves like a machine part that gradually rubs away. This explanation is incomplete and can be discouraging. Osteoarthritis is an active biological process. Joint cells respond to mechanical stress, injury, inflammation, ageing and genetic influences. Cartilage breakdown occurs alongside attempts at repair. Bone changes shape, the joint lining can become inflamed and muscles may weaken. Normal movement does not simply use up a fixed amount of cartilage. Suitable physical activity usually strengthens supporting tissues and improves joint function. The modern model therefore treats osteoarthritis as a whole joint disorder. It is not proof that someone exercised too much or failed to protect their joints. The whole joint is involved A movable joint includes more than the smooth surfaces visible on a simple diagram. Cartilage covers the bone ends and reduces friction during movement. The bone beneath the cartilage is called subchondral bone. It absorbs and distributes forces passing through the joint. The synovium lines the joint capsule and produces synovial fluid. Ligaments guide and stabilise movement, while muscles control load and alignment. In the knee, menisci also distribute force and contribute to stability. Tendons connect muscles to bone and help move the joint. Osteoarthritis can affect all these structures. The relative contribution differs between joints and between individuals. What happens to cartilage Articular cartilage is a smooth, resilient tissue covering the ends of bones within many joints. It contains specialised cells called chondrocytes. Healthy cartilage distributes pressure and allows low friction movement. It has limited direct blood supply and depends on its surrounding environment for nutrition. In osteoarthritis, cartilage composition and structure change. The surface can become rough, develop cracks and lose thickness. Cartilage loss is important, but it does not explain every symptom. Cartilage itself contains very few pain sensing nerves. Pain usually arises from other tissues, including bone, synovium, capsule, ligaments, tendons and surrounding muscles. Bone remodelling and osteophytes Bone responds continuously to the forces passing through it. In osteoarthritis, the subchondral bone can become thicker and its internal structure can change. Small areas of bone damage and repair may contribute to pain. Fluid filled spaces called subchondral cysts can also develop. New bone may form around the joint margins. These bony outgrowths are called osteophytes. Osteophytes are part of the joint's remodelling response. They may restrict movement or alter shape, but they are not always painful. The presence of an osteophyte on an X ray does not prove that it causes a person's symptoms. Why osteoarthritis hurts Pain in osteoarthritis is influenced by tissue changes, inflammation, mechanical loading and nervous system processing. It is not a direct measurement of cartilage loss. Bone marrow changes, synovitis, capsule strain, tendon problems and muscle fatigue can all contribute. Pain sensitivity may increase when pain has persisted for a long time. Sleep disturbance, stress, mood and previous pain experiences can alter how strongly pain is felt. This does not mean that pain is imagined. It means that pain is a protective experience produced by several interacting biological and psychological processes. Two people with similar X rays can have very different symptoms. Treatment should therefore respond to the person, not the image alone. Primary osteoarthritis Primary osteoarthritis develops without one single preceding disease or injury that fully explains it. It usually reflects several interacting risk factors. Age related tissue change, inherited susceptibility, body weight, muscle strength, joint shape and lifetime loading may all contribute. Primary does not mean that the cause is known to be ageing alone. It means that no specific underlying joint disorder has been identified. The pattern may affect several characteristic sites. Hand, knee, hip and spinal osteoarthritis can occur in the same person. Generalised osteoarthritis is sometimes used when several joint regions are affected, particularly in people with a strong inherited tendency. Secondary osteoarthritis Secondary osteoarthritis develops in a joint with a recognised predisposing condition or previous damage. A major ligament injury, fracture involving the joint surface or meniscal injury can alter mechanics and lead to post traumatic osteoarthritis. Developmental abnormalities can change joint shape. Hip dysplasia and some childhood hip disorders can increase later hip osteoarthritis risk. Previous inflammatory arthritis, joint infection, avascular necrosis or metabolic disease can also damage joint tissues. Recognising a secondary cause can affect investigation, prevention and surgical planning. It does not imply that symptoms are more or less genuine. Age as a risk factor Osteoarthritis becomes more common with increasing age. Joint tissues may repair less efficiently, and exposure to previous injury accumulates. Age does not make osteoarthritis inevitable. Many older adults retain good joint function, while younger adults can develop secondary osteoarthritis. Symptoms should not be dismissed because someone is older. Persistent pain and functional loss deserve assessment and treatment. Similarly, a young person with joint pain should not be labelled with osteoarthritis without considering injury, inflammatory disease or structural abnormalities. Age changes probability. It does not determine the diagnosis by itself. Body weight and metabolic influences Living with overweight or obesity increases the risk of knee osteoarthritis and can worsen symptoms in weight bearing joints. Additional body mass increases the force passing through the hips, knees and feet during everyday movement. Body fat also produces signalling molecules that may influence inflammation and tissue metabolism. This may partly explain associations with hand osteoarthritis. Weight is only one factor and should be discussed without blame. Pain, disability, medicines, income, sleep and food access can all affect weight management. Any sustainable weight loss can help when appropriate. NICE advises that a 10% reduction is likely to provide more benefit than 5%, although smaller changes still matter. Previous injury Joint injury is an important risk factor, especially when it damages cartilage, menisci, ligaments or the joint surface. Anterior cruciate ligament injury and meniscal damage increase later knee osteoarthritis risk. A fracture extending into a joint can do the same. Good rehabilitation helps restore strength, movement and control after injury. It cannot guarantee that osteoarthritis will never develop. Repeated instability or returning to demanding activity before recovery may increase abnormal loading. A history of injury also changes the differential diagnosis. Current pain may come from instability, tendon problems or another structural lesion rather than osteoarthritis alone. Occupational and repetitive loading Some occupations expose joints to repeated heavy loading, kneeling, squatting, lifting, vibration or hand use. Risk depends on intensity, duration, technique, recovery time and individual joint structure. Work is rarely the only cause. Reasonable workplace adaptation can reduce aggravating load while preserving employment and activity. Complete avoidance of movement is usually unhelpful. The aim is to vary tasks, improve technique and build physical capacity. Occupational health, physiotherapy or ergonomic assessment may help when work repeatedly triggers symptoms. Genetics and joint shape Osteoarthritis can run in families, particularly hand and generalised osteoarthritis. Many genes each make small contributions to risk. Inherited risk is not destiny. It interacts with injury, body weight, muscle strength, joint shape and other exposures. Some people are born with joint shapes that distribute force unevenly. Hip dysplasia is one example. Leg alignment can influence which part of the knee carries more load. Alignment alone does not determine pain or treatment. A health problems in the family supports the overall pattern but cannot confirm osteoarthritis without compatible symptoms and examination findings. The typical pain pattern Osteoarthritis pain is usually related to using or loading the affected joint. Knee pain may increase with stairs, prolonged walking or rising from a chair. Hip osteoarthritis often causes groin, buttock or upper thigh pain. Pain can sometimes be felt at the knee instead. Hand osteoarthritis may hurt during gripping, pinching, opening containers or prolonged fine work. Pain may settle with rest early in the condition. More advanced disease can cause rest pain or sleep disturbance. Activity related pain is a useful clue, not a perfect rule. Tendon injury, mechanical back pain and other disorders can produce a similar pattern. Brief morning stiffness People with osteoarthritis often feel stiff after waking or after remaining still. This is sometimes called gelling. Morning stiffness typically lasts no longer than 30 minutes. Movement often loosens the joint, although excessive load may later increase pain. NICE supports clinical diagnosis in people aged 45 or over with activity related pain and no morning stiffness or stiffness lasting 30 minutes or less. The time threshold is a guide rather than a biological dividing line. Osteoarthritis flares can occasionally produce longer stiffness. Persistent prolonged stiffness, particularly with soft joint swelling or systemic symptoms, should raise concern about inflammatory arthritis. Crepitus Crepitus describes grating, crackling, crunching or popping felt or heard during joint movement. It can occur when joint surfaces, tendons or other tissues move. Knee crepitus is common in people with and without osteoarthritis. Crepitus alone does not establish disease severity. A painless noisy knee does not necessarily require treatment. When crepitus accompanies activity related pain, stiffness and reduced movement, it contributes to the clinical pattern. Sudden painful locking after injury suggests a different mechanical problem and may require separate assessment. Bony enlargement and deformity Osteoarthritis can produce firm bony enlargement around a joint. This differs from the soft, boggy swelling typical of active synovitis. Progressive remodelling can alter alignment. A knee may become more bowed or knock kneed, and a finger may deviate. Deformity does not always correlate with pain. Some visibly enlarged finger joints are only mildly uncomfortable. Rapid deformity, marked instability or severe loss of function needs reassessment. Another arthropathy or previous injury may be contributing. Treatment focuses on pain, function and the person's priorities rather than appearance alone. Heberden's and Bouchard's nodes Heberden's nodes are bony enlargements beside the distal interphalangeal joints nearest the fingertips. Bouchard's nodes occur beside the proximal interphalangeal joints in the middle of the fingers. The nodes can develop gradually or become tender and inflamed during a flare. They may later remain firm with less pain. Their distribution supports hand osteoarthritis, especially when combined with thumb base pain and activity related symptoms. They should not be confused with rheumatoid nodules, gouty tophi or soft synovial swelling. Examination helps distinguish these findings. Knee osteoarthritis Knee osteoarthritis may affect the inner, outer or kneecap related compartments. Symptoms depend on which tissues and activities are involved. Pain often increases with walking, stairs, squatting or rising. Stiffness after sitting and crepitus are common. A small effusion can occur. Bony enlargement, reduced extension, quadriceps weakness and altered alignment may develop. A feeling of giving way can result from pain inhibition, weakness or instability. It does not always mean a ligament has torn. Sudden severe swelling, heat or inability to bear weight is not a routine osteoarthritis presentation and requires urgent assessment. Hip osteoarthritis Hip osteoarthritis commonly causes deep groin pain, although discomfort may occur in the buttock, thigh or knee. Walking distance may fall, and putting on footwear can become difficult. Internal rotation often becomes painful and restricted. Lateral hip pain over the outer bony prominence may arise from gluteal tendon disease rather than the hip joint itself. Back disease can also refer pain towards the hip or leg. Numbness, weakness or pain below the knee may suggest nerve involvement. A careful examination helps identify whether the hip joint is the main pain source. Osteoarthritis and rheumatoid arthritis are different Osteoarthritis is primarily a whole joint structural and biological disorder. Rheumatoid arthritis is a systemic autoimmune inflammatory disease. Typical osteoarthritis pain worsens with joint use and morning stiffness is brief. Rheumatoid stiffness often lasts longer than 30 minutes and may exceed an hour. Rheumatoid arthritis commonly causes persistent soft swelling, warmth and tenderness in several joints. The small joints of both hands or feet are often affected symmetrically. Rheumatoid arthritis may also cause fatigue, malaise, reduced appetite, fever or weight loss. These systemic features are not typical of uncomplicated osteoarthritis. No feature is perfectly exclusive. Osteoarthritis can be bilateral, and rheumatoid arthritis can begin in an uneven or limited pattern. Other important differential diagnoses Gout can cause sudden severe pain, heat, swelling and redness. The big toe is common, but gout can affect other joints. Calcium pyrophosphate crystal arthritis can cause an acute hot swollen knee, wrist or another joint, especially in older adults. Tendon and bursal disorders cause pain around rather than within a joint. Movement patterns and local tenderness can help distinguish them. Fracture, osteonecrosis, referred spinal pain and neuropathic pain may mimic osteoarthritis. Malignancy is uncommon but must be considered when pain is progressive, unexplained and accompanied by systemic or focal warning features. The acute hot swollen joint A suddenly painful, hot and swollen joint is not assumed to be osteoarthritis. Septic arthritis must be excluded urgently. Septic arthritis is infection within a joint. Delay can cause rapid joint destruction, sepsis and death. Fever may be absent, especially in older or immunosuppressed people. The person can still be seriously unwell. Gout and crystal arthritis can look very similar. Finding crystals does not always exclude simultaneous infection. Urgent assessment may require joint aspiration, blood tests, cultures and immediate specialist treatment. Diagnosis is usually clinical NICE recommends diagnosing osteoarthritis clinically without routine imaging in a typical presentation. In someone aged 45 or over, the characteristic pattern is activity related joint pain with no morning stiffness or stiffness lasting 30 minutes or less. The clinician also assesses function, joint distribution and examination findings. Age and stiffness criteria support rather than replace clinical judgement. A person can have osteoarthritis below age 45, especially after injury or with an underlying structural problem. A clinical diagnosis avoids unnecessary radiation, delay and overemphasis on imaging changes that may not cause symptoms. When imaging is not needed Routine X rays are not required to confirm a typical osteoarthritis presentation. MRI is also unnecessary in most cases. Imaging can reveal age related changes in people without pain. It can also appear mild in someone with substantial symptoms. Requiring an X ray before starting exercise or weight management creates an unnecessary barrier to effective care. Repeated imaging is not used simply to measure whether symptoms have worsened. Management is guided mainly by pain, function and clinical change. The absence of imaging does not mean that the condition is being dismissed or undertreated. When imaging may help Imaging is appropriate when the presentation is atypical or another diagnosis is suspected. Examples include major trauma, rapid deterioration, persistent severe night pain, focal neurological signs or unusual age and joint distribution. An X ray may support surgical planning or identify deformity, fracture, osteonecrosis or another bone lesion. Ultrasound can assess synovitis, effusion, tendons or guide some injections. It is not routinely needed to diagnose uncomplicated osteoarthritis. MRI may be selected for specific structural questions. Incidental findings must be interpreted cautiously. What an X ray may show Typical radiographic features include non uniform joint space narrowing, osteophytes, subchondral sclerosis and cysts. Joint space narrowing is an indirect sign of cartilage loss because cartilage itself is not clearly visible on a standard X ray. Sclerosis means increased bone density beneath the joint surface. Cysts are small fluid related spaces within bone. Alignment and deformity can also be assessed. These features may support the diagnosis and surgical planning. Radiographic severity does not reliably predict pain intensity. Treatment should never be based on the image alone. Blood tests are not routine confirmation tests There is no blood test that confirms osteoarthritis. Typical osteoarthritis does not require inflammatory markers or autoimmune antibodies. Blood tests may be used when inflammatory arthritis, infection, gout, metabolic disease or another systemic condition is suspected. Rheumatoid factor and anti CCP antibodies should not be ordered as broad screening tests for every painful joint. A positive rheumatoid factor can occur without rheumatoid arthritis. Some people with genuine rheumatoid arthritis have negative antibodies. Results must therefore be interpreted with the person's symptoms and background and evidence of clinical synovitis. Therapeutic exercise is first line treatment NICE recommends tailored therapeutic exercise for everyone with osteoarthritis. This can include local strengthening and general aerobic fitness. Exercise improves pain, function and quality of life when performed regularly. Benefits develop through stronger muscles, better control and increased capacity. The programme should match the affected joint, health conditions, current ability and valued activities. Supervised sessions can help with technique, confidence and progression. They are particularly useful after long inactivity or repeated setbacks. Exercise remains relevant in advanced osteoarthritis and while awaiting surgery, provided it is adapted safely. Strengthening exercise Strong muscles help absorb force and control joint movement. Quadriceps and hip muscle training are important in knee osteoarthritis. Hip osteoarthritis programmes may target hip, trunk and lower limb strength. Hand programmes can address grip without repeatedly provoking painful pinch. Strengthening can use body weight, resistance bands, machines or everyday tasks. No single method suits everyone. Correct progression matters more than expensive equipment. Consistency over months produces greater benefit than occasional intense sessions. Pain that suggests a new injury, acute inflammation or neurological problem should be assessed before progression. Weight management For people living with overweight or obesity, weight loss can reduce pain and improve function and quality of life. Any sustained reduction is likely to help. NICE explains that losing 10% of body weight is likely to be more beneficial than losing 5%. The goal should remain realistic and chosen with the person. Repeated judgement or unrealistic targets can damage engagement. Dietary support may need to consider diabetes, food insecurity, cultural diet, mobility and previous weight loss attempts. Exercise has benefits even without weight loss. Treatment should not be withheld while someone works towards a weight goal. Pacing and activity modification Pacing balances activity and recovery. It avoids both prolonged inactivity and repeated cycles of overactivity followed by collapse. Large tasks can be divided into smaller stages. Difficult activities may be alternated with easier ones. Temporary modification is useful during a flare. The aim is a graded return rather than permanent avoidance. Changing technique can reduce joint strain. Higher chairs, two handed lifting and task rotation are practical examples. Occupational therapy can help preserve work, household roles and personal care through equipment and adaptation. Footwear Comfortable, well fitting footwear can improve stability and reduce pressure during lower limb osteoarthritis. A broad toe box can help big toe or forefoot symptoms. A secure heel and suitable sole may improve confidence during walking. Footwear does not reverse osteoarthritis. Its value depends on comfort, balance, occupation and the affected joint. Expensive specialist shoes are not automatically superior. A podiatrist can advise when deformity, diabetes or complex foot mechanics are present. New numbness, skin breakdown or colour change requires assessment rather than a footwear change alone. Walking aids NICE recommends considering walking aids for lower limb osteoarthritis. Sticks, crutches, frames and rollators can improve safety or reduce joint load. For one painful hip or knee, a stick is commonly held in the opposite hand. Individual assessment remains important. Correct height and technique prevent avoidable wrist, shoulder or balance problems. Using an aid is not evidence of failure. It may increase walking distance, independence and participation. The aid should be reviewed if mobility changes or it appears to worsen posture or falls risk. Braces, insoles and supports NICE does not recommend routinely offering braces, insoles, tape, splints or supports to everyone with osteoarthritis. They may help when there is joint instability or abnormal biomechanical loading and exercise alone is ineffective or unsuitable. A thumb splint can reduce painful loading for selected hand osteoarthritis tasks. It should not unnecessarily immobilise the hand. Knee braces can be uncomfortable and benefit is variable. Fit, skin health and actual functional change should be reviewed. Devices should support movement, not replace an effective exercise programme without a clear reason. Medicines are adjuncts Medicines may reduce pain enough to support exercise, sleep or essential activity. They do not repair cartilage or reverse the whole joint process. NICE recommends using pharmacological treatments alongside non pharmacological care and at the lowest effective dose for the shortest time. Choice depends on the joint, symptom severity, pregnancy, age, other medicines and gastrointestinal, kidney, liver and cardiovascular risk. A medicine that is suitable for one person may be unsafe for another. Over the counter availability does not guarantee safety. Treatment should be reviewed and stopped when benefit is absent or risks outweigh improvement. Topical NSAIDs A topical non steroidal anti inflammatory drug is applied to the skin over the painful joint. NICE recommends offering a topical NSAID for knee osteoarthritis. It advises considering one for osteoarthritis affecting other joints. Topical NSAIDs are often a practical first medicine for knee or hand osteoarthritis because systemic exposure is usually lower than with tablets. The medicine should be applied according to instructions, with hand washing and avoidance of broken skin or eyes. Local irritation can occur. Kidney, cardiovascular, gastrointestinal and interaction risks are lower than with oral NSAIDs but are not necessarily zero. Oral NSAIDs An oral NSAID may be considered when topical treatment is ineffective or unsuitable. Before prescribing, clinicians assess gastrointestinal bleeding, kidney injury, liver toxicity and cardiovascular risk. Age, pregnancy, dehydration, anticoagulants, antiplatelets, steroids, kidney disease, heart failure and previous ulcer disease can alter safety. NICE recommends gastroprotection, such as a proton pump inhibitor, while a person with osteoarthritis takes an oral NSAID. Different NSAIDs have different risk profiles. The lowest effective dose should be used for the shortest necessary period. Paracetamol has limited evidence Paracetamol was once routinely recommended for osteoarthritis. Current NICE guidance states that there is no strong evidence of benefit. It should not be offered routinely. NICE limits consideration to infrequent short term use when other pharmacological options are contraindicated, not tolerated or ineffective. Some individuals report benefit, but continued use should depend on meaningful improvement rather than habit. Excess dosing can cause severe liver injury. Combination cold, flu and prescription products may contain paracetamol without the person realising. Limited benefit does not mean that a person should replace it independently with a riskier medicine. Opioids are not routine treatment Weak opioids should not be offered routinely for osteoarthritis. They may only be considered infrequently for short term relief when other options cannot be used or have failed. NICE advises not offering strong opioids for osteoarthritis because harms outweigh benefits. Opioids can cause constipation, nausea, sleepiness, confusion, falls and breathing suppression. Dependence and withdrawal can develop. Long term use may provide little sustained functional benefit. Increasing the dose can increase harm without restoring activity. Anyone already taking opioids should receive a careful review and gradual plan where change is appropriate. Abrupt unsupervised withdrawal can be harmful. Intra articular corticosteroid injections A corticosteroid can be injected into an affected joint to reduce inflammation and pain temporarily. NICE advises considering an injection when other pharmacological treatments are ineffective or unsuitable, or to support therapeutic exercise. Expected relief is short term, usually around two to ten weeks. An injection does not restore cartilage or provide a permanent solution. The treatment is most useful when a temporary pain reduction enables rehabilitation, an important event or recovery from a flare. Benefit varies. Lack of response should prompt review of the diagnosis and treatment plan rather than automatic repeated injections. Injection limitations and risks A joint infection must be considered before injection. A hot swollen joint should not be injected as routine osteoarthritis without appropriate assessment. Temporary pain flare, bruising, skin colour change and local tissue effects can occur. Blood glucose may rise for several days in people with diabetes. Monitoring advice should be individualised. Infection after injection is uncommon but serious. Increasing pain, heat, swelling, fever or illness afterwards needs urgent assessment. Repeated injections require careful judgement because long term benefit is limited and cumulative tissue effects remain a concern. When surgery becomes an option Joint replacement is considered when pain, stiffness, deformity or reduced function substantially affects quality of life. NICE recommends referral when appropriate non surgical management has been ineffective or is unsuitable. A person does not have to try every possible medicine before referral. Some medicines may be unsafe or offer little benefit. Referral is based on clinical impact and shared decision making rather than one X ray grade or questionnaire score. The decision should consider the person's goals, surgical risk, expected benefit and willingness to undergo rehabilitation. Hip and knee replacement Joint replacement removes damaged joint surfaces and replaces them with artificial components. Hip and knee osteoarthritis are common reasons for surgery. Most people seek surgery because pain and functional restriction remain substantial despite non surgical care. Replacement can produce major improvement, but it does not guarantee a painless or completely normal joint. Recovery requires rehabilitation and can take months. Muscle strength and general health influence recovery. Risks include infection, blood clots, dislocation, stiffness, persistent pain, nerve or vessel injury and later implant wear.

Osteoarthritis is an active whole joint disease rather than simple wear and tear. Diagnosis is usually clinical, and the most important treatments are tailored exercise, weight management when appropriate and practical support, with medicines and surgery added according to symptoms, function and risk.