Is bone repair possible in damaged, arthritic knees?

Ross Hauser, MD., Danielle R. Steilen-Matias, MMS, PA-C

This article is part of series of articles on knee osteoarthritis. In this article we will talk specifically about the damage done to the bones of the knees in progressive arthritis.

How your bone changes, adapts and tries to survive advancing knee osteoarthritis.

In the weight-bearing knee joint, bone constantly adapts to the load demands placed on the joint. For instance:

  • If you were to gain a lot of weight, the bone slowly adapts to support that weight.
  • If you perform a repetitive and physically challenging motion with high demand on your knees, the bones in your knees slowly adapt themselves to support that type of activity.
  • If you suffer from knee degenerative wear and tear, the bones in your knees slowly adapt themselves to provide extra stability by developing bone spurs. The bone spurs try to provide the stability and prevent hyperextension caused by weakened and damaged knee ligaments.

How does the bone adapt? By remodeling its structure. The bone is redefining itself by breaking itself down and reassembling itself to provide the knee the stability and function as best as the bones can do it.

This is obviously not a perfect system. Degenerative Disease is Nature’s Way. All living things and all joints including knees, will eventually breakdown. But like all creatures and creations, the knee has an inherent desire to survive. Your knee knows you need it to walk and function, your knee does the best it can to help you.  Sometimes it patches itself together.

In your knee’s rush to survive, it is reshaping bone at an accelerated pace – this makes inferior and weaker bone

When degenerative arthritis occurs, the bone of the knee starts to die. This is the diagnosis of knee osteonecrosis. Knee osteonecrosis can be a slow and methodical process or it can be a super accelerated degenerative problem diagnosed as Spontaneous osteonecrosis of the knee (SONK). In both of these problems the bones in your knees lose or have the blood supply to them severely limited or cut off. If your knees are “breaking down fast” and talk has turned to surgical options, knee osteonecrosis and Spontaneous osteonecrosis of the knee may have already been explained to you by your orthopedist surgeon.

As mentioned, your knee has a survival mechanism. It is always trying to repair itself. Unfortunately when the situation is dire, the knee’s remedies do not meet the challange. This is why so many knee replacements are performed. But your knee is trying. Your knee is in a rush to repair itself. Your knee’s repair mechanism’s main objective is to stabilize itself so it does not “rub itself the wrong way.” How does it do this? By encasing itself in bone spurs. Your knee thinks that if it can’t rub itself the wrong way, it won’t hurt.

We have two problems here.

  • The first problem is that knee stability should never come as a result of bone spurs. Bone spurs are Nature’s last best way to keep you on your feet, albeit very painfully.
  • Second, the situation is made much worse because, in your knee’s rush to repair itself, the bone the knee is creating is not “good bone.”

No one wants to produce inferior bone. When you produce inferior bone you go to knee replacement. Knee replacement is offered to patients who have painful knee degenerative deformities, loss of motion, and no cartilage. This comes from the rapid production of inferior bone in your knee.

Chondral, osteochondral, and subchondral bone lesions. “I have all that!”

This article is part of a series about the avoidance of knee replacement. Not every patient can avoid knee replacement. In some patients the knee has become so deformed with bone spurs, it is locked in place, does not bend, and your toes may be pointed at a significant degree sideways that knee replacement may be the only option for a decent quality of life. When a patient contacts us about their significant knee damage, we offer them the best realistic assessments of what regenerative medicine injections can do.

If you are reading this article it is very likely that you already had an MRI. You probably also have a copy of the report. In that report may be concerns surrounding chondral (cartilage damage), osteochondral (cartilage and bone underneath the cartilage damage), and subchondral (which may involve cysts and inflammation into the marrow) lesions.

Painful knee degenerative deformities, loss of motion, and no cartilage. Did weak and damaged bone cause all this? Yes, but it starts with weakened knee ligaments

Knee degeneration, “bone on bone,” is thought to be caused by the breakdown of the articular cartilage that covers the thigh and shin bones where they meet in the knee, the loss of cartilage on the back of the patella or knee cap, and the breakdown of the meniscus padding between the thigh and shin bones. What causing this breakdown? Degenerative destructive joint movement. If your knee is unstable, it wobbles. Anything that wobbles causes excessive degeneration. What causes wobbling and instability? The breakdown of the soft tissue, namely the ligaments of the knee that holds the bones in place.

Those of us who practice Prolotherapy, as we will explain below, understand knee degeneration as a whole knee disease. One problem, “no cartilage,” is not what is sending you to a recommendation to knee replacement. The whole knee is a problem, the ligaments, the tendons, synovial inflammation, bone destruction, and remodeling. They are all equally guilty of destroying your knee. So treating one problem will not prevent the other problems from continuing their destruction of your knee.

A surprising finding that your bone may be the biggest problem and why you may be racing to knee replacement

What are we seeing in this image below?

In the illustration below, the last panel shows advanced osteoarthritis, a breakdown of cartilage and the development of bone on bone. We are also showing a breakdown and remodeling of bone. All those bumpy bone spurs sitting at the top of the shin bone is the bone remodeling itself to protect itself and stop the knee from hypermobility, the action of rubbing itself the wrong way.

You may have been shown an x-ray of your knee that shows those bumpy bones. People who come into our center tell us that their knees are bone on bone because their cartilage has worn away. This is true. However, as we have outlined above, it is not that simple. Here we are going to show you that your cartilage wore away because your knee becomes unstable due to ligament and tendon microdamage and wear and tear and this caused a continuous degenerative knee motion and degenerative damage to the bone which caused the cartilage damage and caused your knee to grow bone in the form of bone spurs and inferior bone.

Knee Regeneration

You are making inferior bone

Let’s look at some revealing research.

Professor Tuhina Neog of Boston University School of Medicine, published her research in the journal Therapeutic advances in musculoskeletal disease (1) in which she describes the “Clinical significance of bone changes in osteoarthritis.” Here are some of the points she made:

  • There is mounting evidence that degenerative wear and tear of the subchondral bone (bone under the cartilage) plays a much more important role in osteoarthritis than thought.
  • Surgical specimens from persons with osteoarthritis have demonstrated that subchondral bone changes, including subchondral bone attrition which is a flattening or depression of the subchondral bony surface, are common. (Which also makes knee replacement tricky if the bone is subpar).

Further, in its desire to quickly repair and remodel itself to meet the challenges of degenerative joint disease, the bone increases its turnover rate and produces a far inferior bone with less mineralized than normal bone.

Your bone is damaging your cartilage

With alterations in its properties, the subchondral bone may be less able to absorb and dissipate energy, thereby increasing forces transmitted through the joint and predisposing the articular surface to deformation. It has been proposed that these changes in the subchondral bone could adversely affect the biomechanical environment of the overlying cartilage, predisposing the cartilage to subsequent loss of integrity.

The problem of inflammation is it dissolving your good bone? Is it rebuilding good bone? Is it rebuilding bad bone? What is the inflammation doing to your knees?

Inflammation is a difficult problem for many doctors who practice in the world of anti-inflammatory medications to understand. They understand the research that says non-steroidal anti-inflammatory medications can be very harmful to healing, they also understand the significant problems, even joint destruction caused by corticosteroids injections. But they cannot grasp the concept of inflammation as healing medicine.

The difficulty in doctors determining the difference between regenerative treatments (which require inflammation to heal) and non-regenerative conservative care (anti-inflammatory medicine) was highlighted in research from doctors in Germany who were exploring alternatives to knee replacement surgery. Writing in the medical journal Therapeutic Advances in Musculoskeletal Disease (3) they note that doctors are often confused by the term “conservative care.” Conservative knee care of course means, non-surgical treatments and anti-inflammatory medications.

Amazingly, treatments such as Platelet Rich Plasma, Stem Cell Therapy, and Prolotherapy are thought of, if thought of at all, after the use of anti-inflammatories and painkillers derail and impede the natural healing process of the body. We damage the inflammatory healing process when inflammation is needed the most.

Our treatment: Injecting healing inflammation to repair osteoarthritic bone in the knee

In this section, we will examine the role of inflammation and bone repair.

This is research published in the Journal of Orthopaedic Trauma (3) lead by the  Academic Department of Trauma & Orthopaedic Surgery, University of Leeds, Leeds, United Kingdom. The research examines the role of anti-inflammatory medications and acute broken bone damage. Here are the research take-home points:

  • In fracture healing – the state of inflammation dominates the initial phase of healing, but the ideal magnitude and duration of the process for an optimal outcome remains obscure.
    • What is being said here? The bone needs inflammation to heal – knowing what the right amount of inflammation is, is difficult for doctors to understand.
  • Non-steroidal anti-inflammatory drugs frequently administered for pain management after trauma fracture (and in surgery) continue to be a cause of concern for a successful bone repair response because they stop the inflammatory healing process.

Anti-inflammatories compromise the broken bone’s ability to heal properly. What are they doing then to your osteoarthritic knee?

Stem cell signal the healing of bone repair

One of the most studied factors in stem cell repair is perhaps one of the most intriguing – the “paracrine effect.” This is where stem cells introduced into a damaged area assess the damage and then sends out chemical signals to nearby cells to start repairing the damage.

An August 2021 study published in the Frontiers in cell and developmental biology (x) offered a fascinating introduction to how cells talk among themselves. “Osteoarthritis affects the cartilage and entire joint tissues, including the subchondral bone, synovium, and infrapatellar fat pads. The physiological and pathological changes in these tissues affect the occurrence and development of osteoarthritis. Understanding complex crosstalk among different joint tissues and their roles in osteoarthritis initiation and progression is critical in (understanding) the pathogenic mechanism of osteoarthritis.”

To help with this understanding the researchers examined the the various mechanisms by which chondrocytes, synovial cells (synovial fibroblasts and macrophages), mast cells, osteoblasts, osteoclasts, various stem cells communicate, including paracrine signaling, local microenvironment, co-culture, extracellular vesicles (exosomes), and cell tissue engineering. The researchers this offered comprehensive summary of key cells that might be targets of future therapies for osteoarthritis .

  • In one study doctors from Columbia’s National University looked at the ability of stem cells derived from human adipose (fat) tissue to repair surgical bone lesions in animal models. The results demonstrated that stem cells induced bone regeneration mainly by releasing paracrine factors (chemical messages) that “jump started’ the repair process.(5)
  • This was supported by later research from Japan in a paper titled “The paracrine effect of adipose-derived stem cells inhibits osteoarthritis progression.”(6)

Stem cells can repair bone at the level of the micro world

In a very recent study, doctors in China focused on the crucial function of stem cells in bone regeneration by looking at the “osteogenic microenvironment,”  the micro world of the non-repaired joint. They examined why joints don’t heal and how they could be repaired with stem cells.

They centered on the role of inflammation in changing the microenvironment from non-healing to healing. In a damaged joint, the body reacts through two main mechanisms – remove damaged tissue, repair damaged tissue. If the body removes more than it can repair you have degenerative joint disease.

What they found was controlled inflammation brought the healing cells into the joint and the “raw material” to start rebuilding – simultaneously. As the building materials arrived the healing cells arrived. A balance was reached as repair exceeded removal the joint was revitalized.

Their conclusion in the scientific language with our explanations added:

“The results indicated that conditioned medium from inflammatory cytokine-activated MSCs (stem cells “inspired to heal” by pro-inflammatory protein signals) can:

  • significantly promote osteoblast proliferation (bone remodeling and repair),
  • migration (getting to the site of the damage),
  • differentiation (multiply their numbers once at the site of the wound),
  • and mineralization and ultimately enhance osteogenesis (bone repair) through paracrine mechanisms (the stem cells created a blueprint for repair and provided directions to repair cells on how to get to the site of the damage).
  • These findings present a new direction for the clinical application of stem cells.”(7)

Bone disintegration and RANKL inhibitors

As we mentioned above, joint repair is through two mechanisms:

  • (1) removing bone damage to  make way for
  • (2) new bone remodeling. In new research doctors have found that not only do stem cells jump-start the repair process, they also negotiate with the breakdown process to prevent overzealous destruction by RANKL (scientifically Receptor activator of nuclear factor kappa-B ligand).

For those of you who have been prescribed RANKL inhibitors, it may have been explained to you that your body is producing too much of this protein from the Tumor Necrosis Family, (a family of cells that cause cell death.) What RANKL does is secrete acids to disintegrate bone. This is a beneficial function when controlled, as explained above, it is simply out with the old bone, in with the new, the skeletal system grows and gets stronger through this function. It is not beneficial when too much material is removed, thus the prescriptions for RANKL inhibitors.

Doctors in Japan examined patients with medication-induced jaw bone loss. When they intravenously introduced stem cells, they found that not only did the stem cells send repair signals, they also sent signals to the osteoclasts (bone cells that absorb damaged bone) to regulate the amount of bone they were absorbing. In other words, the stem cells stopped the degenerative process so they could fix the damaged bone – they inspired a new bone recycling process using the damaged bone.(8)

When doctors recommend to patients that they need joint replacement surgery, they base this mainly on the diagnosis of bone disintegration in the joint – the diseased bone must be amputated and replaced.

The need to find an effective way to fix bone defects in osteoarthritis is one of the most serious problems facing doctors today. This is why researchers have focused their attention on tissue regeneration therapies including mesenchymal stem cell therapyStem Cells have been used for the treatment of osteogenesis imperfect (extremely fragile bones), osteonecrosis (bone death) of the femoral head, osteoporosis, rheumatoid arthritis and osteoarthritis with good success.(9)

Caring Medical and Rehabilitation Research: Stem Cell Prolotherapy for knee pain

In a study published in the journal Clinical Medicine Insights. Arthritis and musculoskeletal disorders by our Caring Medical research team, our doctors examined the use of a simple, cost-effective regenerative treatment using direct injection of bone marrow stem cells into osteoarthritic joints in combination with dextrose Prolotherapy. Seven patients with hip, knee or ankle osteoarthritis received two to seven treatments over a period of two to twelve months. All patients reported improvements with respect to pain, as well as gains in functionality and quality of life. Three patients, including two whose progress with another therapy had plateaued or reversed, achieved complete or near-complete symptomatic relief, and two additional patients achieved resumption of vigorous exercise.

“We have explored whole bone marrow injection in combination with dextrose prolotherapy as a cost-effective approach with the potentially broad application for osteoarthritis in non-specialized settings. Our initial experience has been encouraging, as all patients experienced significant gains in treatment periods of 2–12 months without adverse events.”(10)


We occasionally see patients where the bone has deformed due to unresolved joint instability with continued joint usage. In a ball and socket joint, such as the hip, the head of the femur bone should be round. But as the ligament damage allows for more joint instability the bone continues to take the brunt of each step, flattening and producing bony overgrowths. Stem cell Prolotherapy has the potential to save your joint from being destroyed but there has to be a realistic expectation if this treatment can work or if the joint is too far gone.  Stem cell Prolotherapy cannot make a flattened bone round again. These cases end up requiring joint replacement surgery.

Do you have a question about your knee pain? You can get help and information from our Caring Medical Staff

1 Neogi T. Clinical significance of bone changes in osteoarthritis. Arthritis research & therapy. 2012 Mar 8;14(2):A3. [Google Scholar]
2 Wehling P, Moser C, Maixner W. How does surgery compare with advanced intra-articular therapies in knee osteoarthritis: current thoughts. Therapeutic advances in musculoskeletal disease. 2016 Jun;8(3):72-85. [Google Scholar]
3 Giannoudis PV, Hak D, Sanders D, Donohoe E, Tosounidis T, Bahney C. Inflammation, bone healing, and anti-inflammatory drugs: an update. Journal of orthopaedic trauma. 2015 Dec 1;29:S6-9. [Google Scholar]
4 Parrilli A, Giavaresi G, Ferrari A, Salamanna F, Desando G, Grigolo B, Martini L, Fini M. Subchondral bone response to injected adipose-derived stromal cells for treating osteoarthritis using an experimental rabbit model. Biotech Histochem. 2017 Mar 20:1-11. [Google Scholar]
5. Linero I, Chaparro O. Paracrine effect of mesenchymal stem cells derived from human adipose tissue in bone regeneration. PLoS One. 2014 Sep 8;9(9):e107001. doi: 10.1371/journal.pone.0107001. eCollection 2014. [Google Scholar]
6. Kuroda K, Kabata T, Hayashi K, Maeda T, Kajino Y, Iwai S, Fujita K, Hasegawa K, Inoue D, Sugimoto N, Tsuchiya H. The paracrine effect of adipose-derived stem cells inhibits osteoarthritis progression. BMC musculoskeletal disorders. 2015 Sep 3;16(1):236. [Google Scholar]
7. Li C, Li G, Liu M, Zhou T, Zhou H. Paracrine effect of inflammatory cytokine-activated bone marrow mesenchymal stem cells and its role in osteoblast function. J Biosci Bioeng. 2015 Aug 24. [Google Scholar]
8. Ogata K, Katagiri W, Hibi H. Secretomes from mesenchymal stem cells participate in the regulation of osteoclastogenesis in vitro. Clin Oral Investig. 2016 Oct 29. [Google Scholar]
9. Wimpenny I, Markides H, El Haj AJ. Orthopaedic applications of nanoparticle-based stem cell therapies. Stem Cell Research & Therapy 2012, 3:13. [Google Scholar]
10 Hauser RA, Orlofsky A. Regenerative injection therapy with whole bone marrow aspirate for degenerative joint disease: a case series. Clinical Medicine Insights: Arthritis and Musculoskeletal Disorders. 2013 Jan;6:CMAMD-S10951.


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