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What is bone on bone arthritis?
Bone on bone arthritis is the plain-language name for advanced osteoarthritis, the stage where the cartilage that cushions a joint has worn down so far that the bone surfaces touch each other directly. It is not a formal diagnosis, but it is the phrase patients hear in the clinic room, and it is usually accurate.
A healthy joint has two things working for it. The ends of the bones are capped with articular cartilage, a smooth layer that lets the surfaces glide, and the joint is bathed in synovial fluid that lubricates and cushions.
Cartilage is remarkable material. It is slicker than ice on ice, and it absorbs load every time you take a step.
In osteoarthritis, that cartilage thins and roughens over years. Once it is gone in a region of the joint, nothing separates the two bone surfaces, and every step transmits load straight through raw bone. That is what people mean by bone on bone arthritis.
What bone on bone arthritis looks like on an X-ray
On an X-ray, bone on bone arthritis shows up as a lost gap between the bones, along with three companion findings I look for in every film.
- Joint space narrowing. Cartilage does not appear on an X-ray, so we measure it by the dark gap between the bones. When that gap closes, the cartilage is gone.
- Osteophytes (bone spurs). Extra bone forms at the edges of the joint as the body tries to stabilize a surface that has become unstable.
- Subchondral sclerosis. The bone just under the missing cartilage thickens and turns bright white on the film because it is absorbing forces it was never designed to take.
- Subchondral cysts. Small fluid-filled pockets appear in that overloaded bone.
Surgeons grade arthritis on X-ray from 0 to 4 using the Kellgren-Lawrence scale. Grade 4 is the one patients recognize as bone on bone.
One caution I give patients often: the X-ray and the symptoms do not always match. I have seen grade 4 films from people who still walk three miles a day, and I have seen grade 2 films from people in real trouble. We treat the patient, not the picture.
What does bone on bone arthritis feel like?
Bone on bone arthritis usually feels like a deep, dull ache inside the joint that is worse with activity and worse at night. Patients describe it as a toothache in the knee or hip rather than a sharp, pinpoint pain.
Here is what I hear most in clinic:
- Pain that starts with activity, then shows up at rest and in bed
- Stiffness for the first several minutes after sitting, driving, or sleeping
- Grinding, crunching, or clicking when the joint moves (crepitus)
- Swelling and warmth around the joint after a busy day
- Loss of motion: trouble straightening the knee fully or putting on socks and shoes
- A sense that the joint may buckle or give way
- A limp, or a shorter walking distance than last year
Night pain is the symptom I pay the most attention to. When arthritis starts stealing sleep, it has stopped being a nuisance.
What causes bone on bone arthritis?
Bone on bone arthritis is caused by cartilage loss that outpaces the joint’s limited ability to repair itself. Several factors speed that loss.
- Age and cumulative use. Decades of loading a joint gradually wear the surface.
- Prior injury. A meniscus tear, an ACL tear, or a fracture that involved the joint surface can start the clock early. This is called post-traumatic arthritis, and I see it in patients in their forties.
- Alignment. Bowlegged or knock-kneed alignment concentrates load on one side of the knee, which is why so much arthritis begins in a single compartment.
- Body weight. Extra load accelerates wear in the knees and hips specifically.
- Genetics. If your mother had both knees replaced, your risk is higher.
- Inflammatory arthritis. Rheumatoid and psoriatic arthritis damage cartilage through a different mechanism and can end at the same place.
What does not cause it: cracking your knuckles, using stairs, or staying active. Motion is good for cartilage. Inactivity weakens the muscles that protect the joint.
Can bone on bone arthritis be reversed?
No. Bone on bone arthritis cannot be reversed, because adult articular cartilage has no blood supply and cannot regenerate once it is lost. Nothing available today (not supplements, not injections, not stem cell marketing) has been shown to rebuild a worn-out joint surface.
Here is what I tell my patients: we cannot change the X-ray, but we can very often change how you feel and what you are able to do. Those are different goals, and only one of them requires new cartilage.
Cartilage restoration research is active and promising. It is not yet a treatment for a joint that has already worn through.
How long can you live with bone on bone arthritis?
There is no fixed timeline. Some people manage bone on bone arthritis comfortably for years with weight management, therapy, and periodic injections, while others reach the end of nonsurgical options within a season.
Waiting is a reasonable choice. Waiting forever is not free.
When patients postpone treatment for years, three things tend to happen: the muscles around the joint weaken from disuse, the leg can drift into deformity as one side of the joint collapses, and the other hip, knee, or back starts hurting from the limp. Every one of those makes recovery from eventual surgery slower.
After more than twenty years and over 700 joint replacements a year, my honest answer is that the right time is not a date on a calendar. It is the point where the joint is running your schedule instead of the other way around.
What are the treatment options for bone on bone arthritis?
Treatment for bone on bone arthritis starts with everything short of surgery, and those measures work better than most patients expect even at the advanced stage.
Nonsurgical treatment for bone on bone arthritis
- Weight management. Each pound lost takes roughly four pounds of force off the knee with every step. Ten pounds makes a real difference.
- Physical therapy and strengthening. Strong quadriceps and hip muscles unload the joint and improve stability. Therapy is the closest thing we have to a cornerstone treatment.
- Low-impact exercise. Cycling, swimming, water walking, and the elliptical keep the joint moving without pounding it. Motion circulates the synovial fluid that lubricates the surface.
- Anti-inflammatory medication. Oral or topical NSAIDs reduce pain and swelling. Discuss these with your physician if you have kidney, stomach, or heart concerns.
- Injections. Corticosteroid injections calm inflammation for weeks to months. Hyaluronic acid injections supplement the joint fluid in selected knees. Our nonsurgical joint pain treatment page covers each option in detail.
- Bracing and walking aids. An unloader brace or a cane in the opposite hand can meaningfully reduce load. A cane is not a defeat. It is a tool.
| Treatment | What it does | Typical relief | Who it suits best |
|---|---|---|---|
| Weight management | Lowers the force crossing the joint. Each pound lost removes about four pounds of knee load per step. | Builds over weeks to months; lasts while the weight stays off. | Anyone carrying extra weight. A 5 to 10 percent loss is enough to change symptoms. |
| Physical therapy and strengthening | Builds quadriceps, glute, and hip strength so muscle absorbs load that would otherwise reach bone. | Often noticeable within 4 to 8 weeks; holds with continued exercise. | Nearly everyone. The highest-value first step at any grade. |
| Low-impact exercise | Cycling, swimming, water walking, and the elliptical keep the joint moving and circulate lubricating fluid. | Ongoing while the routine continues. | Patients who stopped exercising because of pain and are losing strength. |
| Topical anti-inflammatory gel | Delivers an NSAID through the skin with far less systemic exposure than a pill. | Hours per application, one to four times daily. | Knee arthritis, and anyone whose stomach, kidney, or heart risk rules out oral NSAIDs. |
| Oral anti-inflammatory medication | Reduces joint inflammation and pain systemically. | While the medication is being taken. | Short courses for flares, at the lowest effective dose, with physician review. |
| Corticosteroid injection | Places a strong anti-inflammatory inside the joint. | A few days to about three months; spaced no closer than three months. | Flares, or bridging to a planned trip or surgery date. |
| Hyaluronic acid injection | Supplements natural joint fluid to improve lubrication. | Variable. Up to about six months when it works, and no benefit for some. | Selected knees. Guidelines do not recommend it routinely; coverage varies. |
| Unloader brace or cane | Shifts load off the worn side. A cane is held in the hand opposite the painful leg. | Immediate while it is being used. | Arthritis confined to one side of the knee, or a shrinking walking distance. |
| Joint replacement | Resurfaces the worn bone ends with metal and highly durable plastic. | Usually lasting. About 9 in 10 knee implants and 89 percent of hip implants remain in place at 15 years. | Rest or night pain in a joint that no longer responds to the measures above. |
Relief figures are typical ranges from the orthopaedic literature, not guarantees. Response varies with age, activity level, joint, and overall health.
When joint replacement becomes the right answer
Joint replacement is worth discussing when pain persists at rest or at night, nonsurgical care has stopped working, and the joint is limiting the things that matter to you. Not before.
In surgery, the worn surfaces are removed and resurfaced with metal and highly durable plastic. For many of my patients I use Mako® robotic-assisted technology, which builds a three-dimensional plan from a CT scan and helps place the implant to that plan. (I serve as a paid consultant to Stryker, the manufacturer of the Mako platform.)
The results are among the most reliable in orthopedic surgery. More than 90 percent of patients get lasting relief from a total knee replacement or a total hip replacement, and most modern implants are still functioning well at 15 to 20 years. If only one part of the knee is worn, a partial knee replacement may preserve the rest.
The American Academy of Orthopedic Surgeons also publishes patient guidance on arthritis of the knee.
When should you see an orthopaedic surgeon about bone on bone arthritis?
Schedule an evaluation when joint pain has lasted more than a few weeks, wakes you at night, changes how you walk, or has stopped responding to over-the-counter measures. You do not need a referral, and you do not need to be ready for surgery to be seen.
Most first visits end with an X-ray, an exam, and a plan that does not involve an operating room. Coming in early rather than late keeps more options on the table.
Dr. Cory Calendine is a board-certified, fellowship-trained orthopedic surgeon and founding partner of the Bone and Joint Institute of Tennessee, 3000 Edward Curd Lane, Franklin, TN 37067. To schedule an evaluation, call (615) 791-2630 or request an appointment online. He cares for patients from Franklin, Brentwood, Nashville, Spring Hill, Murfreesboro, Nolensville, and across Middle Tennessee.
Watch: what arthritis actually is
Here is the short version of everything above, in about forty seconds.
Medical disclaimer: This article is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified orthopaedic provider about your individual condition. Individual results vary.
References
- Katz JN, Arant KR, Loeser RF. Diagnosis and treatment of hip and knee osteoarthritis: a review. JAMA. 2021;325(6):568-578. PubMed
- Kolasinski SL, Neogi T, Hochberg MC, et al. 2019 American College of Rheumatology and Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee. Arthritis Rheumatol. 2020;72(2):220-233. PubMed
- Kohn MD, Sassoon AA, Fernando ND. Classifications in brief: Kellgren-Lawrence classification of osteoarthritis. Clin Orthop Relat Res. 2016;474(8):1886-1893. PubMed
- Messier SP, Gutekunst DJ, Davis C, DeVita P. Weight loss reduces knee-joint loads in overweight and obese older adults with knee osteoarthritis. Arthritis Rheum. 2005;52(7):2026-2032. PubMed
- Evans JT, Walker RW, Evans JP, Blom AW, Sayers A, Whitehouse MR. How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet. 2019;393(10172):655-663. PubMed
- Evans JT, Evans JP, Walker RW, Blom AW, Whitehouse MR, Sayers A. How long does a hip replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet. 2019;393(10172):647-654. DOI
