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Knee Pain & Problems
Most knee pain comes from wear-and-tear arthritis, overuse or a sports injury, and much of it eases with strengthening exercise, weight and activity changes. A knee you can’t stand on after an injury, a hot, swollen knee with fever, or a swollen, painful calf needs care right away.
Get urgent or emergency care if:
- After an injury you can’t put weight on the leg, the knee looks deformed or out of place, or you felt a pop and the knee swelled up fast. Go to urgent care or an emergency department. The NHS advises urgent help if your knee is very painful, you can’t move it or put weight on it, or it is badly swollen or has changed shape (NHS (opens in a new tab)). Orthopaedic surgeons advise prompt treatment if you hear a pop and feel the knee give out, have severe pain, can’t move the knee, begin limping or have swelling at the injury (AAOS OrthoInfo (opens in a new tab)).
- A hot, red, swollen knee with a fever, or feeling hot, cold or shivery. Get care the same day. This can be a sign of infection (NHS (opens in a new tab)). Septic arthritis is a serious joint infection that should be treated as soon as possible, usually in hospital (NHS (opens in a new tab)).
- Pain and swelling in the calf or leg — throbbing pain, swelling, or red or darkened skin, usually in one leg — can be a blood clot (deep vein thrombosis, DVT), which needs prompt care (NHS (opens in a new tab), CDC (opens in a new tab)). A burst Baker’s cyst can look the same, so don’t assume it is “just the cyst” (NHS (opens in a new tab)). Call 911 if leg pain or swelling comes with shortness of breath or chest pain — a clot may have reached the lungs (NHS (opens in a new tab)).
- After a knee replacement: a fever, chills, drainage from the wound, increasing redness or swelling, or knee pain that keeps getting worse with activity and at rest can mean infection; increasing calf pain or new swelling in the calf, ankle and foot can mean a clot — tell your surgeon right away (AAOS OrthoInfo (opens in a new tab), NHS (opens in a new tab)). Sudden shortness of breath or chest pain: call 911.
Don’t wait for a chiropractic, acupuncture or massage appointment for any of these.
What causes knee pain?
The knee is the largest joint in the body and one of the most easily injured: bones, cartilage, two cushioning menisci, four main ligaments and strong tendons all have to work together (AAOS OrthoInfo (opens in a new tab)). Knee problems happen at every age, and the most common disease affecting the knee is osteoarthritis (MedlinePlus (opens in a new tab)). The NHS links common patterns to likely causes, while warning not to diagnose yourself (NHS (opens in a new tab)):
- Pain and stiffness in both knees, mild swelling, more common in older people: osteoarthritis.
- Pain between the kneecap and shin from repeated running or jumping: tendonitis (see Jumper’s knee).
- Knee unstable or giving way, can’t straighten it, perhaps a pop at injury: a torn ligament, tendon or meniscus (see Meniscus tears and Ligament injuries).
- Warm and red, worse with kneeling: bursitis. Hot and red with sudden, very bad pain: gout or septic arthritis (see Swelling).
- Teenagers with pain and swelling below the kneecap: Osgood-Schlatter disease (see Knee pain in teens).
Knee osteoarthritis
About 33 million U.S. adults have osteoarthritis, and the knees are among the joints it most often affects (CDC (opens in a new tab)). In this “wear-and-tear” arthritis, usually in people 50 and older, the cartilage gradually wears away and becomes frayed and rough, the space between the bones narrows, and painful bone spurs can form (AAOS OrthoInfo (opens in a new tab)). Risk factors include age, being a woman, excess weight, an earlier knee injury or surgery, and genetics (AAOS guideline summary (opens in a new tab)). Meniscus and ligament injuries can lead to arthritis years later (AAOS OrthoInfo (opens in a new tab)).
Symptoms: pain that usually builds slowly; stiffness and swelling that make the knee hard to bend and straighten, often worse in the morning or after sitting; flares after vigorous activity; locking, creaking or grinding; and a feeling of weakness or buckling (AAOS OrthoInfo (opens in a new tab)). There is no cure, but many treatments relieve pain and keep people active (AAOS OrthoInfo (opens in a new tab)). A fuller MBHA guide to osteoarthritis is on the way.
How is knee pain diagnosed?
A doctor asks about your symptoms, examines the knee’s movement, stability and your walk, and often orders X-rays, which show arthritis and bone injuries; MRI shows menisci, ligaments and cartilage best (AAOS OrthoInfo (opens in a new tab), AAOS OrthoInfo (opens in a new tab)). Many ligament injuries can be diagnosed with a careful exam alone (AAOS OrthoInfo (opens in a new tab)). Fluid may be drawn from a swollen joint to look for infection or crystals (AAOS OrthoInfo (opens in a new tab), ACR (opens in a new tab)).
When to see a provider (not an emergency): the NHS suggests seeing a doctor if knee pain doesn’t improve within a few weeks, and getting prompt advice if the knee locks, gives way or clicks painfully — painless clicking is normal (NHS (opens in a new tab)). Some injuries raise your risk of arthritis later, so see a doctor if symptoms change how your knee feels or works (AAOS OrthoInfo (opens in a new tab)).
Side by side
Six approaches compared
For every condition we look at the same six approaches: what each involves, what it typically costs, and what a patient can realistically expect.
| Approach | What it involves | Estimated cost | What to expect |
|---|---|---|---|
| Conventional medicine (AMA) | Exercise and physical therapy, weight loss, canes and braces, topical and oral NSAIDs, steroid injections, ACL reconstruction for unstable knees, and knee replacement when other care fails. Arthroscopy is not recommended for worn knees. | Medicare Part B covers medically necessary PT (20% coinsurance after the deductible). Knee replacement and other costs being researched. | Exercise and NSAIDs help many people modestly; steroid shots help for a short time. Knee replacement greatly reduces pain for most people with severe arthritis. |
| Chiropractic | Knee and lower-leg manipulation or mobilization alongside exercise — never on a freshly injured, hot or swollen knee before a medical check. | About $90–$200 for a first visit and $55–$100 for follow-ups without insurance; Medicare covers only spinal adjustments. | Limited evidence: fair for short-term relief of knee arthritis and runner’s knee, limited for longer term; a U.S. guideline advises against adding it to exercise. |
| Acupuncture | Needle (sometimes electro-) acupuncture for knee arthritis pain, alongside exercise and medical care. | About $125–$230 for a first private visit and $90–$185 for follow-ups; community clinics about $50–$90. Medicare doesn’t cover it for knees. | Mixed: better than no treatment, but often little or no better than sham needling. A U.S. guideline conditionally recommends it. Side effects usually minor. |
| Herbal medicine | Turmeric (curcumin), glucosamine/chondroitin, and capsaicin cream rubbed on the knee. | Cost estimate being researched. | Capsaicin cream may help a little; turmeric shows early promise; glucosamine and chondroitin are uncertain at best. Some supplements interact with blood thinners. |
| Massage therapy | Whole-body or knee-focused Swedish massage for comfort — never on a hot, swollen knee or a calf that might hold a clot. | One national chain: about $70–$90 a month for a 60-minute membership session. Other costs being researched. | Two U.S. trials found short-term relief of knee arthritis symptoms that faded over months; a U.S. guideline still recommends against it as an arthritis treatment. |
| MBHA Wellness Coach | Thigh and hip strengthening, low-impact activity, tai chi, weight goals, footwear, pacing and a gradual return to sport. | Cost estimate being researched. | Supports — never replaces — medical care. Tai chi matched physical therapy for knee arthritis in one trial, and weight loss eases symptoms. |
Approach 1 of 6
Conventional medicine (AMA)
The steps below focus on knee osteoarthritis; injuries and other conditions have their own sections further down. Treatment should start with self-managed steps such as home exercise, weight loss and appropriate use of medicines (AAOS guideline summary (opens in a new tab)).
1. Exercise and physical therapy
Exercise is strongly recommended for knee osteoarthritis in the 2019 American College of Rheumatology (ACR) guideline, which found support for a broad menu of options, from walking to strengthening to water exercise (ACR/AF guideline, 2019 (opens in a new tab)). Orthopaedic surgeons also recommend supervised or home exercise (AAOS guideline summary (opens in a new tab)), and a physical therapist can design a program to build leg strength and flexibility (AAOS OrthoInfo (opens in a new tab)).
How big the benefit is remains debated. A 2024 Cochrane review of 139 trials (12,468 people) found exercise probably improves pain, function and quality of life in the short term, but the gains were of uncertain clinical importance, and most participants knew which treatment they were getting (Lawford et al., Cochrane, 2024 (opens in a new tab)). No one type of exercise beat the others.
2. Weight, canes and braces
- Weight loss is strongly recommended for people with knee arthritis who are overweight; benefits grow with more weight lost and are greater when combined with exercise (ACR/AF guideline, 2019 (opens in a new tab)).
- A cane helps pain and function (AAOS guideline summary (opens in a new tab)).
- Braces: the ACR strongly recommends tibiofemoral knee braces when arthritis is making walking, stability or pain hard to manage, and conditionally recommends kneecap (patellofemoral) braces (ACR/AF guideline, 2019 (opens in a new tab)). An “unloader” brace shifts weight off the worn side of the knee (AAOS OrthoInfo (opens in a new tab)).
- Wedged shoe insoles are not recommended for knee arthritis (AAOS guideline summary (opens in a new tab), ACR/AF guideline, 2019 (opens in a new tab)).
3. Pain relievers (by class)
- Topical NSAID gels are strongly recommended for knee arthritis and should be considered before pills, because less medicine reaches the rest of the body (ACR/AF guideline, 2019 (opens in a new tab)).
- Oral NSAIDs such as ibuprofen or naproxen improve pain and function but should be used with caution, or avoided, by people with heart disease, heart failure or chronic kidney disease (AAOS OrthoInfo (opens in a new tab)).
- Acetaminophen is only conditionally recommended because its benefit in trials is very small (ACR/AF guideline, 2019 (opens in a new tab)).
- Opioids: orthopaedic surgeons say strong evidence shows opioids, including tramadol, don’t improve knee arthritis pain or function and cause more side effects (AAOS guideline summary (opens in a new tab)).
We don’t list doses; ask your doctor or pharmacist what is safe for you.
4. Injections
- Corticosteroid (cortisone) shots are strongly recommended by the ACR (ACR/AF guideline, 2019 (opens in a new tab)) and give short-term relief (AAOS guideline summary (opens in a new tab)). Your doctor may limit how many you have, because frequent repeated injections can increase joint damage (AAOS OrthoInfo (opens in a new tab)).
- Hyaluronic acid (“gel” shots, viscosupplementation): the evidence is mixed at best. The AAOS guideline summary says moderate evidence shows these shots are not recommended for knee arthritis (AAOS guideline summary (opens in a new tab)); AAOS patient information adds that recent research hasn’t found them to significantly reduce pain or improve function, though some people report relief (AAOS OrthoInfo (opens in a new tab)). The ACR conditionally recommends against them but accepts them as a shared decision when other options have failed (ACR/AF guideline, 2019 (opens in a new tab)). A 2022 analysis of 169 trials found only a small pain reduction — less than patients would notice — and more serious side effects than placebo (Pereira et al., 2022 (opens in a new tab)).
5. Arthroscopy (“scoping”) is not recommended for worn knees
Keyhole surgery to clean out or trim a worn knee was once common. A 2017 international panel made a strong recommendation against arthroscopy for nearly all people with degenerative knee disease — with or without arthritis on imaging, clicking or catching, or sudden onset — the possible exception being a knee truly locked so it can’t straighten (Siemieniuk et al., BMJ, 2017 (opens in a new tab)). Two key trials support this: trimming a worn meniscus was no better than sham surgery (Sihvonen et al., 2013 (opens in a new tab)), and in people with arthritis plus a meniscal tear, physical therapy gave similar results to surgery, though 30% of the therapy group went on to have surgery (Katz et al., 2013 (opens in a new tab)). AAOS patient information says arthroscopy may still be suggested for a degenerative meniscal tear (AAOS OrthoInfo (opens in a new tab)), so ask your surgeon what result to expect. The panel’s advice did not cover young people with sports injuries (Siemieniuk et al., BMJ, 2017 (opens in a new tab)).
6. Other surgery
When arthritis pain causes disability despite other treatment, options include an osteotomy (reshaping the shinbone or thighbone to take weight off a worn side), or a partial or total knee replacement (AAOS OrthoInfo (opens in a new tab)). See Knee replacement, and Ligament injuries for ACL reconstruction.
What it costs
- Physical therapy: Medicare Part B covers medically necessary outpatient PT when your provider certifies you need it; you pay 20% of the approved amount after the deductible (Medicare.gov (opens in a new tab)). Cash prices: MBHA cost estimate being researched.
- Knee replacement, office visits, imaging, braces and injections: MBHA cost estimate being researched.
Approach 2 of 6
Chiropractic
Some people with knee arthritis or runner’s knee see a chiropractor for hands-on treatment of the knee and leg, usually with exercise. The research is limited, and some of the best of it was done by physical therapists rather than chiropractors.
What the research says
- Chiropractic review: a 2012 review of manipulative therapy for leg and foot problems, led by an author from a chiropractic college, rated the evidence as “fair” for short-term and “limited” for long-term treatment of knee arthritis and patellofemoral pain, and called for larger, better trials (Brantingham et al., 2012 (opens in a new tab)). It rated ankle sprains the same way; see our ankle guide.
- One positive trial: in a New Zealand trial of 206 people with hip or knee arthritis, manual therapy from physical therapists improved symptoms over usual care for a year, but combining it with exercise therapy added nothing (Abbott et al., 2013 (opens in a new tab)).
- Guidelines are cautious: the ACR conditionally recommends against adding manual therapy to exercise for knee arthritis, finding little extra benefit (ACR/AF guideline, 2019 (opens in a new tab)), and orthopaedic surgeons say manual therapy has very limited scientific support for knee arthritis (AAOS guideline summary (opens in a new tab)).
Safety
- Don’t have a freshly injured, swollen, unstable or deformed knee manipulated until a doctor has checked for a fracture or torn ligament, and never have hands-on treatment of a hot, red knee — see the warning signs at the top of this page.
- If your chiropractor also adjusts your spine: after spinal manipulation, mild soreness or stiffness is common and usually fades within a day; serious problems are rare and may be more likely in people with health problems that raise their risk of injury (NCCIH (opens in a new tab)).
What it costs
- Without insurance: about $90–$200 for a first visit and $55–$100 for follow-ups; an exam plus several weeks of care can total $500–$1,000 (The Pricer (opens in a new tab)).
- Medicare covers only spinal adjustments to correct a subluxation — not treatment of the knee, or X-rays, massage or acupuncture a chiropractor orders; you pay 20% after the deductible (Medicare.gov (opens in a new tab)).
Approach 3 of 6
Acupuncture
Knee arthritis is one of the most-studied uses of acupuncture, and the results are genuinely mixed: acupuncture usually beats no treatment, but often not by much — or not at all — when compared with convincing sham needling (NCCIH (opens in a new tab)).
What the research says
- Cochrane review (2010): 16 trials, 12 of them in knee arthritis. Against sham, acupuncture gave small short-term benefits that fell short of what patients would notice, probably partly from placebo effects; against a waiting list, benefits were clinically relevant, though much may be expectation (Manheimer et al., Cochrane, 2010 (opens in a new tab)).
- JAMA trial (2014): in 282 people over 50 with chronic knee pain, needle and laser acupuncture were modestly better than no treatment at 12 weeks but no better than sham, and benefits had faded by one year (Hinman et al., JAMA, 2014 (opens in a new tab)).
- More positive trials: a U.S. trial of 570 people found acupuncture added to usual care improved function and, by 26 weeks, pain compared with sham (Berman et al., 2004 (opens in a new tab)). A Chinese trial of 480 people found intensive electroacupuncture beat sham at 8 weeks, while manual acupuncture did not at 8 weeks but showed benefits later (Tu et al., 2021 (opens in a new tab)).
- Guidelines disagree: the ACR conditionally recommends acupuncture for knee arthritis, noting its effectiveness is still controversial (ACR/AF guideline, 2019 (opens in a new tab)), while orthopaedic surgeons say it has very limited scientific support (AAOS guideline summary (opens in a new tab)).
If you try it, treat it as an add-on to exercise and medical care, and agree on a trial period.
Safety
Relatively few complications have been reported; problems have come from non-sterile needles and improper technique, so choose a licensed practitioner who uses sterile, single-use needles (NCCIH (opens in a new tab)). No serious side effects occurred in the 2014 JAMA trial (Hinman et al., JAMA, 2014 (opens in a new tab)).
What it costs
Published cash prices run about $125–$230 for a first private visit and $90–$185 for follow-ups; community clinics about $50–$90 a visit (The Pricer (opens in a new tab)). Medicare covers acupuncture only for chronic low back pain, not knee pain (Medicare.gov (opens in a new tab)).
Approach 4 of 6
Herbal medicine
Glucosamine and chondroitin
These are among the most popular joint supplements, but whether they help knee arthritis is still uncertain: studies have been inconsistent, and expert groups disagree (NCCIH (opens in a new tab)). The ACR strongly recommends against glucosamine and chondroitin for knee arthritis, saying the best-quality data show no important benefit over placebo (ACR/AF guideline, 2019 (opens in a new tab)), while the 2021 orthopaedic surgeons’ guideline lists them among supplements that may help, with a warning that the evidence is inconsistent (NCCIH (opens in a new tab)). They don’t reverse arthritis (AAOS OrthoInfo (opens in a new tab)). No major safety problems have turned up, but glucosamine may raise blood sugar in some people, and both have been linked to more bleeding in people taking warfarin (NCCIH (opens in a new tab)).
Turmeric (curcumin)
Early evidence for oral turmeric or curcumin in knee arthritis is positive, but higher-quality research is needed, and it is unclear whether curcumin ointment helps (NCCIH (opens in a new tab)). A 2022 analysis of 15 trials (1,670 people) found curcumin products eased knee pain and stiffness more than placebo in the short term, but the authors urged caution because the studies were low quality and varied widely (Feng et al., 2022 (opens in a new tab)). Turmeric can upset the stomach, liver damage has been reported with highly absorbable curcumin products, and supplements may be unsafe in pregnancy (NCCIH (opens in a new tab)).
Capsaicin cream (from chili peppers)
The ACR conditionally recommends rub-on capsaicin for knee arthritis, noting the benefits in studies were small (ACR/AF guideline, 2019 (opens in a new tab)). Expect burning or redness where you apply it, which usually eases after several days; keep it away from your eyes, nose and mouth, wash your hands after use, don’t use it on broken skin, and don’t cover the area with a bandage or heating pad (MedlinePlus (opens in a new tab)). Rub-on NSAID gels, sold over the counter, are covered under Conventional medicine.
Supplements, NSAIDs and blood thinners: some herbs interact with medicines — for example, ginkgo taken with warfarin raises the risk of major bleeding (NCCIH (opens in a new tab)). If you take any medicine, talk with your provider before using an herbal product (NCCIH (opens in a new tab)), and remember that most people need a blood thinner after knee replacement (AAOS guideline summary (opens in a new tab)). We don’t list doses, and no herb treats a torn ligament, an infected joint or a blood clot.
What it costs
Cost estimate being researched.
Approach 5 of 6
Massage therapy
Massage can feel good and help some people relax, and knee arthritis is one of the few joint problems where massage has been tested in proper trials.
What the research says
- In a 2012 U.S. trial of 125 adults with knee arthritis, eight weeks of hour-long weekly Swedish massage improved pain and function more than usual care, but the advantage was gone by 24 weeks (Perlman et al., 2012 (opens in a new tab)).
- A larger 2019 trial of 222 adults found eight weekly full-body massages beat both light touch and usual care at 8 weeks. Continuing massage every two weeks maintained the improvement but added no benefit over usual care after that, and by one year the groups did not differ. Side effects were minimal (Perlman et al., 2019 (opens in a new tab)).
- The ACR conditionally recommends against massage as an arthritis treatment because studies have been small and at high risk of bias, while acknowledging that massage may have other benefits (ACR/AF guideline, 2019 (opens in a new tab)). NCCIH says the small amount of evidence suggests it may help knee symptoms (NCCIH (opens in a new tab)).
Safety
Never massage a hot, red, swollen knee, or a calf that is painful or swollen — that could be a blood clot. Arthritic joints are sensitive, so a therapist should know how to work with arthritis (NCCIH (opens in a new tab)). Serious problems are rare, but a blood clot, nerve injury or broken bone has been reported, some with vigorous deep-tissue massage or in older adults (NCCIH (opens in a new tab)). After knee surgery, check with your surgeon before any leg massage, since clots in the leg veins are among the most common complications of knee replacement (AAOS OrthoInfo (opens in a new tab)).
What it costs
At one national chain, Massage Envy, a membership runs about $70–$90 a month for one 60-minute session, with a 12-month initial term; prices vary by location (The Pricer (opens in a new tab)). Other costs being researched.
Approach 6 of 6
MBHA Wellness Coach
An MBHA Wellness Coach can help you build the habits that matter most for sore knees, alongside — never instead of — your doctor’s and physical therapist’s care.
Strengthen the thighs and hips
Strong thigh (quadriceps) and hip muscles help keep the kneecap on track; weak or unbalanced muscles are a common factor in runner’s knee (AAOS OrthoInfo (opens in a new tab)), and quadriceps strength matters for recovery from ACL tears (AAOS OrthoInfo (opens in a new tab)). A coach can help you stick with your physical therapist’s program.
Stay active, the low-impact way
- CDC says physical activity is safe for people with arthritis and can reduce joint pain and improve function and mood. It recommends at least 150 minutes a week of moderate activity plus muscle strengthening on at least 2 days, and suggests joint-friendly choices such as brisk walking, cycling, swimming, dancing and tai chi — starting slowly and paying attention to how your body feels (CDC (opens in a new tab)). Swapping jogging or tennis for swimming or cycling puts less stress on the knee (AAOS OrthoInfo (opens in a new tab)).
Tai chi
The ACR strongly recommends tai chi for knee arthritis (ACR/AF guideline, 2019 (opens in a new tab)). In a 2016 trial of 204 people, 12 weeks of tai chi worked as well as standard physical therapy, with benefits lasting a year and greater improvement in mood (Wang et al., 2016 (opens in a new tab)). Tai chi appears safe; reported side effects are minor aches (NCCIH (opens in a new tab)).
Weight
Losing weight reduces stress on the knee, easing pain and improving function (AAOS OrthoInfo (opens in a new tab)); benefits increase with more weight lost and are greater alongside exercise (ACR/AF guideline, 2019 (opens in a new tab)). A coach can help with realistic food and activity goals. An MBHA guide to weight control is on the way.
Footwear and pacing
- Wear shoes suited to your activity (AAOS OrthoInfo (opens in a new tab)); wedged insoles aren’t recommended for knee arthritis (AAOS guideline summary (opens in a new tab)).
- Cut back on what aggravates the knee, such as stairs (AAOS OrthoInfo (opens in a new tab)), and increase training gradually — sudden jumps in how often, how long or how hard you exercise can trigger runner’s knee (AAOS OrthoInfo (opens in a new tab)).
- Self-management programs that teach goal-setting, problem-solving, joint protection and exercise are strongly recommended for knee arthritis (ACR/AF guideline, 2019 (opens in a new tab)), and CDC recognizes over 20 such programs (CDC (opens in a new tab)).
Returning to sport after an injury
Go back gradually once your doctor allows it (AAOS OrthoInfo (opens in a new tab)). After ACL reconstruction, return to sports usually takes 6 to 12 months and depends on full motion, restored strength and endurance, and good balance and control of the leg (AAOS OrthoInfo (opens in a new tab)). Warm up, stretch, and wear kneepads if you work on your knees or play contact sports (AAOS OrthoInfo (opens in a new tab), AAOS OrthoInfo (opens in a new tab)).
Another approach
Patellofemoral pain (“runner’s knee”)
Patellofemoral pain is a dull ache around and behind the kneecap, common in athletes — especially young adults and women — but also in people who don’t play sports. It usually comes on gradually and is worse on stairs, running, jumping, squatting, or after sitting a long time with bent knees. Causes include overuse, sudden increases in training, poor technique or equipment, and weak or unbalanced thigh and hip muscles that let the kneecap track poorly (AAOS OrthoInfo (opens in a new tab)).
It usually improves with simple measures: easing off painful activities, switching to low-impact exercise, ice, NSAIDs, and physical therapy that strengthens the thighs and hips; shoe inserts help some people, and surgery is very rarely needed (AAOS OrthoInfo (opens in a new tab)). It can return if you don’t adjust your training, so keep up the strengthening (AAOS OrthoInfo (opens in a new tab)).
Another approach
Meniscus tears
The menisci are two rubbery, wedge-shaped cushions between the thighbone and shinbone. Young athletes tear them by twisting or pivoting, often along with an ACL tear, while in older adults worn tissue can tear with something as simple as an awkward twist getting out of a chair. You may feel a pop; most people can still walk, but over 2 to 3 days the knee becomes stiff and swollen, and it may catch, lock or give way (AAOS OrthoInfo (opens in a new tab)).
Many tears don’t need immediate surgery: if there’s no locking or ongoing swelling, rest, ice, compression, elevation, NSAIDs and sometimes a steroid injection come first. Tears in the outer edge, which has a good blood supply, may heal or can be stitched; tears in the inner part can’t heal and are trimmed if they keep causing symptoms (AAOS OrthoInfo (opens in a new tab)). For worn (degenerative) tears, trials found trimming no better than sham surgery or physical therapy — see Arthroscopy under Conventional medicine. Recovery takes about 3 to 6 weeks after trimming and 3 to 6 months after a repair (AAOS OrthoInfo (opens in a new tab)).
Another approach
Ligament injuries (ACL and MCL)
ACL tears are among the most common knee injuries — more than 200,000 a year in the U.S. — usually from pivoting, cutting or landing a jump, often without any contact. Female athletes are injured 2 to 8 times as often as males. You may hear a pop and feel the knee give way, with swelling within 24 hours (AAOS OrthoInfo (opens in a new tab)). About half of ACL tears come with other damage, such as a meniscus tear (AAOS OrthoInfo (opens in a new tab)).
Not everyone needs surgery. Rehabilitation alone can work for partial tears without instability, for people who don’t play pivoting or cutting sports, and for less active people. Reconstruction with a tendon graft is encouraged for active people whose knees feel unstable, because ongoing instability can damage the meniscus and cartilage; activity level, not age, should guide the decision (AAOS OrthoInfo (opens in a new tab)). In a Swedish trial of 121 young, active adults, rehab plus early reconstruction was no better at two years than rehab with the option of later surgery, and most of the second group never needed an operation (Frobell et al., 2010 (opens in a new tab)). Children need special techniques to protect growth plates (AAOS OrthoInfo (opens in a new tab)).
MCL and LCL injuries on the inner and outer sides of the knee come from a blow or force that bends the knee sideways, common in football, hockey and skiing. Low-grade tears without other injuries can usually be treated without surgery, using rest, ice, a hinged brace and physical therapy (AAOS OrthoInfo (opens in a new tab)).
Another approach
Patellar tendinitis (“jumper’s knee”)
Pain between the kneecap and shin, often from repeated running or jumping, is usually tendonitis of the patellar tendon (NHS (opens in a new tab)), nicknamed “jumper’s knee” (MedlinePlus (opens in a new tab)). Treatment starts with rest, ice, support and pain relief such as ibuprofen gel, then physical therapy if pain is severe or lasts (NHS (opens in a new tab)). Exercise programs that load the tendon gradually are the mainstay; in a 2026 review of small trials, several progressive strengthening programs worked about as well as each other (Liu et al., 2026 (opens in a new tab)). Doctors typically avoid steroid injections in or around this tendon, because they have been linked to tendon weakening and rupture (AAOS OrthoInfo (opens in a new tab)).
A sudden tearing or popping, then being unable to straighten the knee, a dent below the kneecap or the kneecap riding up the thigh, suggests a torn tendon, which usually needs surgery (AAOS OrthoInfo (opens in a new tab)) — get urgent care. An MBHA guide to tendonitis is on the way.
Another approach
Swelling: bursitis, Baker’s cysts, gout and pseudogout
- Kneecap bursitis (“housemaid’s knee”): a swollen cushion in front of the kneecap, often from constant kneeling or a blow. Rest, ice, elevation and NSAIDs usually work; fever, chills or redness can mean the bursa is infected, which needs prompt antibiotics. Kneepads help prevent it (AAOS OrthoInfo (opens in a new tab)). See our bursitis guide.
- Baker’s cyst: a soft, fluid-filled lump behind the knee, in adults usually caused by an injury, arthritis or gout, and most common between 35 and 70. It often improves when the underlying knee problem is treated, though it can take months to years. Calf pain or swelling that suddenly gets worse may be a burst cyst or a blood clot — get it checked urgently (NHS (opens in a new tab)). See our cysts guide and blood clots guide.
- Gout causes sudden flares of pain, swelling and redness, usually in one joint at a time — often the big toe, but the knee too (MedlinePlus (opens in a new tab)). See our gout guide.
- Pseudogout (CPPD) comes from calcium crystals rather than uric acid and most often strikes the knees; it is more common after 60. An attack typically lasts 7 to 14 days; a specialist may drain the joint and inject a steroid, and no treatment yet dissolves the crystals (ACR (opens in a new tab)). See also our arthritis guide.
A hot, swollen knee can also be an infection, so don’t assume it’s gout — see the warning signs at the top of this page.
Another approach
Knee pain in teens: Osgood-Schlatter disease
Osgood-Schlatter disease is a common cause of knee pain in growing adolescents, especially those in running and jumping sports: repeated pulling by the kneecap tendon irritates the growth plate at the bony bump below the knee, which becomes painful, swollen and tender. Rest, ice, NSAIDs, a strap below the kneecap, and stretching and strengthening usually ease it; continuing sports as tolerated won’t cause long-term damage. Symptoms usually disappear when growth finishes, around 14 for girls and 16 for boys, though the bump may remain, and surgery is rarely needed (AAOS OrthoInfo (opens in a new tab)).
A child’s knee pain isn’t always from the knee: hip problems can sometimes be felt in the thigh or knee. Sudden pain in the hip, thigh or knee, a limp, or not being able to put weight on one leg needs an urgent appointment (NHS (opens in a new tab)) — see our hip guide.
Another approach
Knee replacement: what to expect
Knee replacement swaps the damaged joint surfaces for metal and plastic parts, all of the knee (total) or part of it (partial). It is usually done when other treatments haven’t helped enough and severe pain makes daily activities hard (MedlinePlus (opens in a new tab), NHS (opens in a new tab)). More than 700,000 total knee replacements are done in the U.S. each year, and decisions are based on pain and disability, not age (AAOS OrthoInfo (opens in a new tab)).
- Getting ready: diabetes, severe obesity, smoking and opioid pain relievers are linked to more complications, so surgeons advise tackling them before surgery (AAOS guideline summary (opens in a new tab)).
- Results: most people get a dramatic reduction in pain, though a new knee won’t let you do more than before arthritis. More than 90% of modern total knee replacements still work well after 15 years (AAOS OrthoInfo (opens in a new tab)), and the NHS says most last about 25 years (NHS (opens in a new tab)).
- Recovery: most people go home 1 to 4 days after surgery on crutches or a frame; wait at least 6 weeks to drive after a total replacement and expect to return to work after about 6 to 12 weeks (NHS (opens in a new tab)). Most daily activities resume within 3 to 6 weeks, and doing your exercises makes a big difference (AAOS OrthoInfo (opens in a new tab), MedlinePlus (opens in a new tab)). Walking, swimming, golf, cycling and light hiking are realistic; most surgeons advise against running and jumping for life (AAOS OrthoInfo (opens in a new tab)).
- Risks: serious complications such as joint infection occur in fewer than 2% of patients; blood clots in the leg veins are among the most common complications, so you will likely move early, take a blood thinner and wear compression stockings (AAOS OrthoInfo (opens in a new tab), NHS (opens in a new tab)). Some people have ongoing stiffness, pain or instability (NHS (opens in a new tab)). A fall in the first weeks can damage the new knee, so use your walking aid or handrails on stairs (AAOS OrthoInfo (opens in a new tab)).
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Sources
- AAOS OrthoInfo — Arthritis of the knee (opens in a new tab)
- AAOS — The management of osteoarthritis of the knee (surgical and non-surgical): plain-language guideline summary (PDF) (opens in a new tab)
- AAOS OrthoInfo — Viscosupplementation treatment for knee arthritis (opens in a new tab)
- AAOS OrthoInfo — Common knee injuries (opens in a new tab)
- AAOS OrthoInfo — Patellofemoral pain syndrome (opens in a new tab)
- AAOS OrthoInfo — Meniscus tears (opens in a new tab)
- AAOS OrthoInfo — Anterior cruciate ligament (ACL) injuries (opens in a new tab)
- AAOS OrthoInfo — ACL injury: does it require surgery? (opens in a new tab)
- AAOS OrthoInfo — Collateral ligament injuries (opens in a new tab)
- AAOS OrthoInfo — Patellar tendon tear (opens in a new tab)
- AAOS OrthoInfo — Prepatellar (kneecap) bursitis (opens in a new tab)
- AAOS OrthoInfo — Osgood-Schlatter disease (knee pain) (opens in a new tab)
- AAOS OrthoInfo — Total knee replacement (opens in a new tab)
- NHS — Knee pain (opens in a new tab)
- NHS — What is a knee replacement? (opens in a new tab)
- NHS — Recovering from a knee replacement (opens in a new tab)
- NHS — Complications of a knee replacement (opens in a new tab)
- NHS — DVT (deep vein thrombosis) (opens in a new tab)
- NHS — Baker’s cyst (opens in a new tab)
- NHS — Septic arthritis (opens in a new tab)
- NHS — Tendonitis (opens in a new tab)
- NHS — Hip pain in children (irritable hip) (opens in a new tab)
- MedlinePlus — Knee injuries and disorders (opens in a new tab)
- MedlinePlus — Knee replacement (opens in a new tab)
- MedlinePlus — Tendinitis (opens in a new tab)
- MedlinePlus — Gout (opens in a new tab)
- MedlinePlus — Capsaicin topical (drug information) (opens in a new tab)
- CDC — Osteoarthritis (opens in a new tab)
- CDC — Physical activity and arthritis (opens in a new tab)
- CDC — About venous thromboembolism (blood clots) (opens in a new tab)
- American College of Rheumatology — Calcium pyrophosphate deposition (CPPD) (opens in a new tab)
- Kolasinski et al. — 2019 ACR/Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee (Arthritis Care Res, 2020; PMC) (opens in a new tab)
- Lawford et al. — Exercise for osteoarthritis of the knee (Cochrane, 2024; PubMed) (opens in a new tab)
- Pereira et al. — Viscosupplementation for knee osteoarthritis: systematic review and meta-analysis (BMJ, 2022; PubMed) (opens in a new tab)
- Siemieniuk et al. — Arthroscopic surgery for degenerative knee arthritis and meniscal tears: a clinical practice guideline (BMJ, 2017; PMC) (opens in a new tab)
- Sihvonen et al. — Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear (N Engl J Med, 2013; PubMed) (opens in a new tab)
- Katz et al. — Surgery versus physical therapy for a meniscal tear and osteoarthritis (N Engl J Med, 2013; PubMed) (opens in a new tab)
- Frobell et al. — A randomized trial of treatment for acute anterior cruciate ligament tears (N Engl J Med, 2010; PubMed) (opens in a new tab)
- Liu et al. — Comparative effectiveness of exercise interventions for patellar tendinopathy: systematic review and network meta-analysis (BMC Sports Sci Med Rehabil, 2026; PubMed) (opens in a new tab)
- Brantingham et al. — Manipulative therapy for lower extremity conditions: update of a literature review (J Manipulative Physiol Ther, 2012; PubMed) (opens in a new tab)
- Abbott et al. — Manual therapy, exercise therapy, or both, in addition to usual care, for osteoarthritis of the hip or knee: randomized trial (Osteoarthritis Cartilage, 2013; PubMed) (opens in a new tab)
- Manheimer et al. — Acupuncture for peripheral joint osteoarthritis (Cochrane, 2010; PubMed) (opens in a new tab)
- Hinman et al. — Acupuncture for chronic knee pain: a randomized clinical trial (JAMA, 2014; PubMed) (opens in a new tab)
- Berman et al. — Effectiveness of acupuncture as adjunctive therapy in osteoarthritis of the knee: randomized trial (Ann Intern Med, 2004; PubMed) (opens in a new tab)
- Tu et al. — Efficacy of intensive acupuncture versus sham acupuncture in knee osteoarthritis: randomized trial (Arthritis Rheumatol, 2021; PubMed) (opens in a new tab)
- Feng et al. — Efficacy and safety of curcuminoids alone for knee osteoarthritis: systematic review and meta-analysis (BMC Complement Med Ther, 2022; PubMed) (opens in a new tab)
- Perlman et al. — Massage therapy for osteoarthritis of the knee: a randomized dose-finding trial (PLoS One, 2012; PubMed) (opens in a new tab)
- Perlman et al. — Efficacy and safety of massage for osteoarthritis of the knee: a randomized clinical trial (J Gen Intern Med, 2019; PubMed) (opens in a new tab)
- Wang et al. — Comparative effectiveness of tai chi versus physical therapy for knee osteoarthritis: a randomized trial (Ann Intern Med, 2016; PubMed) (opens in a new tab)
- NCCIH — Glucosamine and chondroitin for osteoarthritis: what you need to know (opens in a new tab)
- NCCIH — Turmeric (opens in a new tab)
- NCCIH — Osteoarthritis: in depth (opens in a new tab)
- NCCIH — Tai chi: what you need to know (opens in a new tab)
- NCCIH — Herb-drug interactions: what the science says (opens in a new tab)
- NCCIH — Spinal manipulation: what you need to know (opens in a new tab)
- NCCIH — Acupuncture: effectiveness and safety (opens in a new tab)
- NCCIH — Massage therapy: what you need to know (opens in a new tab)
- Medicare.gov — Physical therapy services (opens in a new tab)
- Medicare.gov — Chiropractic services (opens in a new tab)
- Medicare.gov — Acupuncture (opens in a new tab)
- The Pricer — Chiropractor and chiropractic treatment cost (opens in a new tab)
- The Pricer — Acupuncture cost (opens in a new tab)
- The Pricer — Massage Envy cost (one national chain) (opens in a new tab)
This page is for education only and is not medical advice. Costs are typical U.S. ranges and estimates; yours will depend on your provider, location and insurance. Talk with your doctor before starting, stopping or combining any treatment. In an emergency, call 911. See our disclaimer.
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