Knee osteoarthritis is often described as “wear and tear,” but that phrase is incomplete. Osteoarthritis affects the entire joint, including cartilage, bone, the joint lining, meniscus, ligaments, and surrounding muscles.
Two people can have similar X-rays and very different symptoms. One may remain active with mild stiffness, while another has substantial pain, swelling, weakness, and difficulty walking.
That is why treatment should not be based on an X-ray grade alone. From my perspective as an orthopedic surgeon, the better question is:
What is driving this patient’s pain, and which treatment best matches the symptoms, examination, imaging, health, and goals?
What is knee osteoarthritis?
Healthy cartilage creates a smooth, low-friction surface over the ends of the thighbone and shinbone. The menisci help distribute pressure, while muscles and ligaments stabilize the knee.
With osteoarthritis, several changes may occur:
- Cartilage becomes thinner or irregular
- The space between the bones narrows on weight-bearing X-rays
- Bone spurs may develop
- The bone beneath the cartilage may become denser or irritated
- The meniscus may degenerate or move outward
- The joint lining may become inflamed
- The knee may lose motion
- The surrounding muscles may weaken
These changes do not always progress at the same rate.
What does knee arthritis feel like?
Common symptoms include:
- Aching pain with walking or standing
- Stiffness after sitting
- Pain on stairs or hills
- Swelling after activity
- Grinding or creaking
- Reduced ability to bend or fully straighten the knee
- Difficulty rising from a chair
- Pain at night
- A sense of weakness or giving way
- Increasing bowlegged or knock-kneed alignment
Sudden severe pain is not always “just arthritis.” A meniscus root tear, insufficiency fracture, bone marrow lesion, gout, infection, or another condition may require a different plan.
What do the stages of knee osteoarthritis mean?
Doctors often describe X-ray severity using the Kellgren-Lawrence scale or plain-language terms such as mild, moderate, and severe arthritis.
Early or mild arthritis
The X-ray may show small bone spurs with little joint-space narrowing. Symptoms may be intermittent and activity-related.
At this stage, treatment often emphasizes strength, activity modification, weight management when appropriate, medication, and selected injections.
Moderate arthritis
Joint-space narrowing and bone spurs become more apparent. Swelling, stiffness, and reduced walking tolerance may become more frequent.
Patients may need a more structured combination of physical therapy, medication, bracing, injections, and activity planning.
Advanced arthritis
The joint space may be severely narrowed or absent in part of the knee. The bone may become denser, alignment may change, and motion may decrease.
Nonsurgical care can still help some patients. Surgery is considered when pain and functional loss remain unacceptable despite reasonable treatment.
Why symptoms and X-rays do not always match
X-rays show structure, not pain.
A patient can have advanced arthritis with surprisingly little discomfort. Another patient can have modest X-ray changes but severe pain from inflammation, a meniscus root tear, a subchondral insufficiency fracture, or a bone marrow lesion.
Weight-bearing X-rays are usually more informative than non-weight-bearing images because they show how the joint space behaves under load.
MRI is not routinely necessary for obvious osteoarthritis, but it may be helpful when:
- Symptoms are out of proportion to the X-ray
- Pain began suddenly
- A fracture or bone marrow lesion is suspected
- The knee locks
- A meniscus root tear is possible
- The diagnosis remains uncertain
- The result would change treatment
First-line treatment: movement, strength, and load management
Exercise is one of the strongest evidence-based treatments for knee osteoarthritis.
The 2021 AAOS clinical practice guideline recommends supervised exercise, unsupervised exercise, and aquatic exercise over no exercise for improving pain and function. The American College of Rheumatology and Arthritis Foundation guideline also strongly recommends exercise for knee osteoarthritis.
A large 2025 BMJ network meta-analysis of randomized trials found that several exercise approaches can improve pain, function, gait, or quality of life. The practical lesson is not that every patient must perform one perfect program. It is that a sustainable program should be matched to the person. Read the BMJ review.
Useful components may include:
- Quadriceps strengthening
- Hip and core strengthening
- Balance training
- Stationary cycling
- Walking on tolerable surfaces
- Pool exercise
- Tai chi
- Flexibility work
- Gradual return to recreational activity
Pain during exercise does not automatically mean damage is occurring. However, exercise should be adjusted when it causes a major flare, increasing swelling, or pain that does not settle.
Learn more about physical therapy at Pacific Bone & Joint.
Does weight loss help?
For patients who are overweight, weight reduction can decrease the load across the knee and may improve pain and function.
The ACR/Arthritis Foundation guideline strongly recommends weight loss for patients with knee osteoarthritis who are overweight or obese. The benefit generally increases as more meaningful weight reduction is achieved, but even a modest change may help.
A 2024 randomized trial published in the New England Journal of Medicine studied semaglutide in people with obesity and moderate knee osteoarthritis. Participants receiving semaglutide plus lifestyle counseling lost more weight and had greater improvement in WOMAC pain than those receiving placebo plus counseling. This supports the relationship between weight reduction and symptoms, but medication decisions require individualized medical evaluation and are not orthopedic treatment for every patient. Read the trial.
Medications for knee arthritis
Medication choice depends on medical history, kidney function, gastrointestinal risk, heart disease, blood thinners, allergies, and other medications.
Options may include:
Topical anti-inflammatory medication
Topical diclofenac can reduce pain with less systemic exposure than an oral anti-inflammatory medication. The ACR guideline strongly recommends topical NSAIDs for knee osteoarthritis.
Oral anti-inflammatory medication
Oral NSAIDs can be effective but are not appropriate for everyone. They may increase the risk of stomach bleeding, kidney problems, fluid retention, or cardiovascular complications.
Acetaminophen
Acetaminophen may provide limited relief for some patients. It is not an anti-inflammatory medication and must be used carefully in patients with liver disease or substantial alcohol intake.
Duloxetine
Duloxetine may help selected patients with chronic osteoarthritis pain, particularly when pain sensitivity, sleep disruption, or overlapping chronic pain conditions are present.
Opioids are generally not a preferred long-term treatment for knee osteoarthritis.
Braces, canes, and shoe strategies
A cane used in the opposite hand can reduce load on a painful knee. An unloader brace may help selected patients with arthritis concentrated in one compartment.
Bracing is most useful when:
- Pain is mainly on one side of the knee
- Alignment contributes to overload
- The brace fits correctly
- The patient can tolerate wearing it
Expensive shoe inserts are not automatically better. The goal is comfort, stability, and a plan that the patient will actually use.
Cortisone injections
A corticosteroid injection may reduce inflammation and provide short-term relief.
AAOS states that intra-articular corticosteroids can provide short-term relief for symptomatic knee osteoarthritis. They do not reverse cartilage loss or correct alignment.
Cortisone may be helpful when:
- The knee is inflamed or swollen
- Pain is interfering with rehabilitation
- A temporary reduction in symptoms would help during a flare
- Surgery is not currently planned or desired
Repeated injections should not become a substitute for reassessing the diagnosis and treatment plan.
Hyaluronic acid injections
Hyaluronic acid, often called a gel injection, is intended to improve the joint environment and reduce symptoms.
Evidence is mixed. AAOS does not recommend routine use for all patients, while some clinicians and patients report meaningful improvement in selected situations.
My clinical perspective is that it may be reasonable to discuss when other nonsurgical treatments have not provided enough relief, particularly when expectations are realistic and coverage or cost is understood.
PRP and BMAC
Orthobiologic treatments are an evolving area.
Platelet-rich plasma
PRP is prepared from the patient’s blood and contains concentrated platelets and signaling proteins. AAOS states that PRP may reduce pain and improve function in symptomatic knee osteoarthritis, but the strength of evidence is limited.
Results can vary because PRP preparation, platelet concentration, injection protocols, and patient selection are not standardized.
Bone marrow aspirate concentrate
BMAC is prepared from the patient’s own bone marrow. It contains platelets, growth factors, signaling proteins, and a small population of progenitor cells.
BMAC may be considered in selected joint-preservation cases, particularly when symptoms and imaging identify a specific cartilage or subchondral-bone target. Current evidence does not establish that BMAC regrows a normal knee or reliably outperforms other injection options for every patient.
Regenerative medicine may be discussed in selected patients when the diagnosis, evidence, and goals align.
What about arthroscopy?
Arthroscopy generally does not provide lasting benefit for aching and stiffness caused primarily by osteoarthritis.
It may still have a role for selected mechanical problems, such as:
- A true locked knee
- A symptomatic loose body
- Certain repairable meniscus tears
- Selected meniscus root tears before arthritis becomes advanced
- Another specific structural problem that matches the symptoms
An MRI finding of a degenerative meniscus tear does not automatically mean arthroscopy is needed.
When is knee replacement considered?
Knee replacement is considered when:
- Pain is persistent and substantial
- Walking, sleep, work, or daily activities are meaningfully limited
- X-rays show arthritis that matches the symptoms
- Reasonable nonsurgical treatments are no longer adequate
- The patient understands the expected recovery, risks, and alternatives
The decision is not based on age or X-rays alone. It is based on the whole clinical picture and the patient’s goals.
Learn more about knee replacement care in Hawai‘i.
Warning signs that need prompt evaluation
Seek timely medical evaluation for:
- Inability to bear weight
- A hot, red, rapidly swollen knee
- Fever with knee pain
- A new deformity
- Calf swelling or shortness of breath
- A true locked knee
- Sudden severe pain after a fall
- Rapid worsening without a clear reason
Dr. Morton’s perspective
I do not treat an X-ray. I treat the person attached to it.
A good plan starts by identifying the main pain generator, understanding how the symptoms affect the patient’s life, and choosing the least invasive treatment that is likely to help.
For one patient, that may be physical therapy and better load management. For another, it may include medication, bracing, an image-guided injection, weight-loss support, or an orthobiologic discussion. For advanced arthritis that continues to limit quality of life, knee replacement may become the most predictable option.
The best treatment is not necessarily the most aggressive treatment. It is the treatment that fits the diagnosis, evidence, health, and goals.
Knee arthritis care in Hawai‘i
Pacific Bone & Joint evaluates knee arthritis, meniscus problems, bone marrow lesions, sports injuries, and persistent knee pain in Honolulu, Waipahu, Hilo, and Kona. Kona visits are by appointment only.
Our team can combine examination, weight-bearing X-rays, ultrasound, MRI review, physical therapy, bracing, medication, image-guided injections, regenerative medicine discussions, and surgical consultation when appropriate.
Call (808) 439-6201 to request an appointment.
This article is educational and does not replace an individualized examination.
Sources and further reading
- American Academy of Orthopaedic Surgeons. Management of Osteoarthritis of the Knee: Evidence-Based Clinical Practice Guideline, Third Edition. 2021.
- Kolasinski SL, et al. 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip, and Knee. Arthritis Care & Research. 2020.
- Yan L, et al. Comparative Efficacy and Safety of Exercise Modalities in Knee Osteoarthritis: Systematic Review and Network Meta-Analysis. BMJ. 2025.
- Marriott KA, et al. Are the Effects of Resistance Exercise on Pain and Function in Knee and Hip Osteoarthritis Dependent on Exercise Volume, Duration, and Adherence?. Arthritis Care & Research. 2024.
- Bliddal H, et al. Once-Weekly Semaglutide in Persons with Obesity and Knee Osteoarthritis. New England Journal of Medicine. 2024.
