Osteoarthritis (Primary Care).Care & specialists in Japan

Osteoarthritis cannot be reversed, but it is highly manageable. Structured exercise, weight loss, topical and oral NSAIDs, and selective injections control symptoms for most patients for years. When the hip or knee reaches end-stage disease, joint replacement effectively cures the joint-specific pain, with 80-90% patient satisfaction and over 95% prosthesis survivorship at 10 years. The underlying cartilage damage does not regrow, but the disease can be brought to a stop in clinical terms.

Osteoarthritis is a wear-and-repair condition of individual joints that causes use-related pain and stiffness under 30 minutes in the morning. Rheumatoid arthritis is an autoimmune inflammatory disease that attacks the small joints symmetrically, produces over an hour of morning stiffness, warm swollen joints, and raised inflammatory markers. Blood tests for rheumatoid factor and anti-CCP help confirm rheumatoid arthritis, and the two are managed by different treatment pathways.

Osteoarthritis is diagnosed clinically in most patients. A clinician confirms use-related joint pain, morning stiffness under 30 minutes, age over 45, and typical examination findings such as crepitus and reduced range of motion. A weight-bearing X-ray is used when surgical decisions are being made or another diagnosis needs to be excluded. MRI and blood tests are not routine in classic presentations.

Kellgren-Lawrence is the standard radiographic grading scale for osteoarthritis severity, scored 0 to 4. Grade 0 is normal; grade 1 shows possible joint space narrowing and tiny osteophytes; grade 2 shows definite osteophytes with possible narrowing; grade 3 shows moderate joint space loss, sclerosis, and bony deformity; grade 4 shows severe joint space loss and large osteophytes. Grade does not always match symptom severity.

The knee carries the largest single burden globally, followed by the hand (especially the base of the thumb and the distal and proximal finger joints), the hip, the spinal facet joints in the neck and lower back, the first metatarsophalangeal joint of the big toe, and the shoulder. Knee, hip, and hand OA together account for the vast majority of clinical disease.

Moderate, structured exercise is one of the most effective treatments for osteoarthritis and does not accelerate joint damage. Strengthening, aerobic, and range-of-motion programmes reduce pain and improve function with effect sizes equivalent to NSAIDs. Pain that settles within 24 hours of exercise is acceptable. High-impact activity on a damaged joint should be modified, but inactivity is more harmful than carefully chosen exercise.

The strongest evidence supports a combination of quadriceps and hip strengthening, low-impact aerobic activity such as cycling or swimming, and range-of-motion work, performed at least twice a week for 12 weeks or more. Tai chi has trial-level evidence equivalent to physiotherapy. Aquatic exercise is useful when pain limits land-based training. A supervised programme outperforms self-directed exercise.

Even a 5% loss of body weight produces measurable knee pain improvement, and 10% roughly halves incident knee OA risk in overweight women. Each kilogram lost reduces knee compressive force by approximately four kilograms per step. Combining weight loss with exercise produces greater pain and function benefit than either alone.

Large randomised trials and meta-analyses have not shown a clinically meaningful benefit of glucosamine or chondroitin over placebo for osteoarthritis pain or progression. The 2019 ACR/AF guideline conditionally recommends against using them. They are well tolerated and not harmful, but the money and effort are better spent on exercise and weight management.

Intra-articular corticosteroid injections are a useful short-term option for moderate-to-severe knee, hip, and hand OA. They typically reduce pain for 4-8 weeks. Most guidelines limit injections to no more than three or four per joint per year and avoid them within three months of planned joint replacement. Repeated injections may cause modest cartilage volume loss over years on MRI.

Evidence for intra-articular hyaluronic acid in knee and hip OA is weak and inconsistent. The 2019 ACR/Arthritis Foundation guideline conditionally recommends against its use. Some patients report benefit, and it remains a second or third-line option in some practices. Coverage and out-of-pocket cost vary widely.

Joint replacement is considered when osteoarthritis pain and functional limitation persist despite at least 12 weeks of structured exercise, weight management, and appropriate medications, especially with night pain, severe loss of mobility, or grade 4 disease on weight-bearing X-ray. Timing balances symptom severity against the patient's age, fitness for surgery, and personal goals.

Modern total hip and total knee replacements have over 95% prosthesis survivorship at 10 years and approximately 85-90% at 20 years in national registry data. Outcomes are best at high-volume centres and in patients with controlled weight, no smoking, and well-managed diabetes. About 1-2% of patients per year require revision surgery for wear, loosening, or infection.

Yes. Post-traumatic osteoarthritis develops in adults under 45 after significant joint injury such as ACL rupture, meniscal tear, intra-articular fracture, or dislocation. Hip dysplasia and femoroacetabular impingement also produce early hip OA. Younger patients are usually managed with conservative care, osteotomy, or hip preservation surgery, with joint replacement deferred when possible.

No. Long-term observational studies have not found that habitual knuckle cracking causes osteoarthritis. The cracking sound is from gas bubbles forming and collapsing in synovial fluid, not joint damage. Crepitus due to OA is a different, coarser grating sensation and is usually accompanied by joint pain or stiffness.

NSAIDs — particularly topical NSAIDs for knee OA and oral NSAIDs for hand and hip OA — produce greater pain relief than acetaminophen and are the preferred pharmacologic first step in current ACR and OARSI guidelines. Acetaminophen has only modest benefit but remains useful for patients who cannot tolerate NSAIDs. Always consider cardiovascular, gastrointestinal, and renal risks before chronic NSAID use.

Mild effusions and a sense of warmth are common in OA flares, especially in the knee. A joint that is bright red, intensely hot, and exquisitely tender, particularly with fever, is not typical OA — it suggests crystal arthritis, septic arthritis, or another inflammatory cause and needs urgent assessment and joint aspiration.

Yes, in part. Twin studies estimate heritability of 40-65% for hand and hip OA and 30-40% for knee OA. Several susceptibility genes have been identified, including GDF5, COL11A1, and DOT1L. Nodal hand OA in women shows particularly strong familial clustering. Lifestyle factors interact with genetic predisposition.

Erosive osteoarthritis is a subtype affecting the hand, usually the distal and proximal interphalangeal joints, with more inflammation, central erosions on X-ray, more pain, and faster progression than typical nodal OA. It primarily affects post-menopausal women and is sometimes mistaken for psoriatic or rheumatoid arthritis. Management includes NSAIDs, topical therapy, splinting, and selective injection.

Conservative management is inexpensive — most exercise programmes can be delivered through public health systems or community physiotherapy, and topical and oral NSAIDs are generic. Intra-articular steroid injections are low-cost. Total hip and knee replacement are the major cost items: in the US, list prices range from USD 30,000 to USD 50,000 with insurance covering most of it; in India and many emerging markets the total package is USD 4,000-8,000.

Some patients report pain flares with cold, damp, or pressure-changing weather, but large studies have not found a consistent objective link. Subjective reports remain real and worth acknowledging; staying warm, layered, and active during cold snaps is reasonable. Climate change is not a major driver of disease, but indoor inactivity during cold months is.

Several investigational disease-modifying OA drugs are in late-stage trials, including the Wnt-pathway inhibitor lorecivivint and the cartilage growth factor sprifermin, with mixed results so far. Cell-based therapies, including PRP and stem cell injections, have weak and inconsistent evidence and are not endorsed by current guidelines. Joint replacement remains the definitive structural answer for end-stage hip and knee disease.