Please contact us if you have a question. The responses are not intended to be medical advice, but are intended to provide information based on the best available evidence for individuals to make informed decisions.

How important is surgical technique, and can I avoid getting more scar tissue after surgery by choosing the right surgeon?

Response: There is no clear answer to this question, however, it appears that surgical technique is important for the best possibility of a good outcome. The practices of an experienced arthrofibrosis surgeon are:

  1. No use of a tourniquet during surgery unless absolutely necessary. Hypoxia (lack of oxygen) is a powerful driver of fibrosis and the use of a tourniquet (or not) during surgery as standard practice is likely to be an important difference between surgeons. However, a tourniquet may sometimes be necessary, for example, during a TKR.
  2. “Releasing” scar tissue not “removing” it with very little use of the arthroscopic shaver, preferring the use of a cautery tool to release scar tissue and prevent bleeding.
  3. Preserving the fat pad. Cutting the fat pad strongly promotes further fibrosis.
  4. Liberal use of local pain anaesthetics to ensure adequate post-op pain control. The following is an example procedure by an experienced arthrofibrosis surgeon, Dr Hackett. Indwelling local pain catheters were placed pre-op by the anaesthesiologist under ultrasound guidance for a continuous ropivacaine infusion that was taken home and controlled by a button press, lasting for 3 days (when pain is usually at its worst). One was an adductor canal block and the other a sciatic block. In addition, a genicular local block was placed during surgery that theoretically lasts 24 hours. Not recommended are femoral nerve blocks (a one time shot) placed pre-op since these have the disadvantage of causing some motor blockade / quad weakness, and they also only last about 1 day, leaving days 2 and 3 painful. The adductor canal block and genicular/sciatic block only block sensory nerves, sparing the motor function of the quads.

The following information is from a nurse practitioner:

“Having worked with many different surgeons in the operating room I can attest that there is a wide variety of operative styles.  Even though the operative report might read nearly identical between doctors, their hand movements, how they handle tissues and with what, how much attention they pay to hemostasis (control of bleeding) as they go, how much “extra” stuff they do, how fast they are, where they put their incisions, whether they close certain layers individually, whether they sprinkle antibiotic powder, do interrupted or running sutures, what instrument they use for dissecting, what local/anaesthesia is used, if any, what materials they use for suturing or implants, whether they preserve the fat pad or not during a primary total knee replacement, etc, etc.”

Other considerations

For somebody who is borderline (has genetics that don’t strongly predispose them to AF), one very small mistake (e.g. exercising too much) or unavoidable factor (e.g. the flu) can push them over the edge towards AF, or they may escape it. However, if a person has strong genetic drivers then it may be difficult or impossible to avoid AF after surgery. 

How big the surgery is appears to be a significant factor in how likely a joint is to be fibrotic afterwards. Cutting bone seems to be one of the most powerful drivers of AF, it releases a lot of the cells and growth factors involved in fibrosis. Hence, the riskiest knee surgeries are ACL reconstruction and total knee replacement (TKR). Both of these surgeries involve cutting major bones.

If the surgery is minor, for example, an arthroscopy, then surgical techniques that minimise bleeding can make a difference, but there are no guarantees. Arthroscopic surgery is a less powerful stressor on the body, but there is significant stress with any surgery1. There is always some bleeding, hypoxia, wound healing and inflammation, and all of these are powerful fibrotic stimuli. 

  1. Dobson, G. P. Trauma of major surgery: A global problem that is not going away. Int J Surg81, 47-54, doi:10.1016/j.ijsu.2020.07.017 (2020).

When is it too late?

Response: This is an important question about which, unfortunately, there has been no proper research. Anecdotally, the first 6 months after the onset of arthrofibrosis (post operation or injury) is the easiest time to stop arthrofibrosis, and for the period of up to a year it may still be possible to do this.

After a year the collagen that makes up the scar tissue is thought to become strongly cross-linked with strong bonds that are particularly difficult for the body to break. This means that the scar tissue can remain in the body long term, instead of being broken down and removed.

Feedback processes between the inflammatory and fibrosis systems of the body become well established, and these processes feed and reinforce each other.

Surgery may re-set the body by removing the scar tissue and some of the special cells (myofibroblasts) that create it, permitting recovery.

However, surgery powerfully stimulates inflammation and wound healing processes. It is these factors that cause arthrofibrosis, and surgery sometimes makes symptoms worse in the long term as the body’s processes become yet more dysregulated.

We can’t predict yet who will benefit from surgery, and who will have a worse outcome. Those that have a lot of inflammation and pain may be at the greatest risk of having worse outcomes, and controlling inflammation should always be a priority.

Should I get a corticosteroid injection into the joint?

Response: This is a tough one, there are pros and cons to having a cortisone (corticosteroid) injection. I’m not able to advise on the best course of action. However, I can provide information so that you’re better informed to make your own decision.  
Pros: corticosteroids help to reduce inflammation in the short term. Most types last about 6 days, and this might help to settle arthrofibrosis if it is soon after surgery.

Cons: Studies indicate that corticosteroids are toxic to cartilage, at least at higher doses and when repeated. 
It’s helpful to know more before proceeding with an injection. Questions to ask are: 

  1. What type of corticosteroid will be used? There are a number of types that have slightly differing actions. All can be toxic to cartilage at higher doses.
  2. What dose will be used? This is really important because the evidence suggests that low doses of injected corticosteroids may be beneficial, at least if they are not repeated often. Studies suggest that higher doses – often the recommended dose – are toxic to cartilage cells and are more likely to cause cartilage damage.

Below are a couple of papers that are publicly available on this topic, and you’ll find more information on doses and types of corticosteroids here. 

Wernecke, C., Braun, H. J. & Dragoo, J. L. The Effect of Intra-articular Corticosteroids on Articular Cartilage: A Systematic Review. Orthop J Sports Med 3, 2325967115581163, doi:10.1177/2325967115581163 (2015).

McAlindon, T. E. et al. Effect of Intra-articular Triamcinolone vs Saline on Knee Cartilage Volume and Pain in Patients With Knee Osteoarthritis: A Randomized Clinical Trial. JAMA 317, 1967-1975, doi:10.1001/jama.2017.5283 (2017).

Zeng, C. et al. Intra-articular corticosteroids and the risk of knee osteoarthritis progression: results from the Osteoarthritis Initiative. Osteoarthritis Cartilage27, 855-862, doi:10.1016/j.joca.2019.01.007 (2019).

Please note that these studies are on osteoarthritis patients, however the effect on cartilage will be the same. 
Here is a quote from McAlindon et. al. 2017. This was a double-blinded trial to prevent bias (neither patient nor accessor knew whether they got the treatment or placebo) using the standard amount “40 mg of triamcinolone administered every 3 months over 2 years into knees with osteoarthritis and inflammation resulted in significantly greater cartilage volume loss and no significant difference in knee pain than did saline injections”. Bear in mind, these injections were repeated for 2 years. 
There is always a placebo effect that is especially strong with knee injections, so it’s necessary to blind trials if possible. People report decreases in pain just from saline injections. 
There are other risks associated with knee injections, including infection and bleeding, and although the risk is small, it does exist. Also, the needle itself causes a small amount of cell death and trauma.
Corticosteroids are typically given with an anaesthetic, which means that there is a short-term reduction in pain. The action of most types of corticosteroids lasts for around 6 days. 

Question: Your article “Pathological Mechanisms…” mentions that influenza can activate or reactivate arthrofibrosis. I’m wondering if you would recommend for or against a flu shot? Last year I got one about the same time I went to an acupuncturist and I ended up losing about 10 degrees of flexion, but not sure which caused it. She advised me to drink a lot of bone broth which I think may have fed the scar tissue development. I was about 9 months after TKR surgery at the time.


As you say, it’s not possible to know what caused your arthrofibrosis to flare up again. The most likely explanation is stress, as this causes an increase in cortisol and other inflammatory markers, and it has a powerful effect on healing.

However, we can look at the possibilities you mentioned.

Flu vaccine: this will cause a temporary increase in inflammation, however, it will be very limited in duration and intensity, so it’s unlikely that this is what caused your decreasing ROM, unless you had a particularly bad reaction. However, even if you did react badly to the vaccine, I suggest that you continue to be vaccinated, since your reaction to the actual flu virus will be much more powerful and longer-lasting if you haven’t developed the immunity that the vaccine provides. The same argument applies to covid vaccines.

Bone broth: this is unlikely to be the cause of decreasing ROM. It contains large amounts of collagen in the form of gelatine, which has a lot of protein (amino acids) in it. Collagen is highly digestible and is broken down into the individual amino acids by the stomach and intestines. However, the collagen (scar tissue) formed in arthrofibrosis is made from proteins that are eaten every day in different types of food. The body decides what type of collagen to make, and where, based on signals from cells that indicate where it’s needed.

It’s true that an inflammatory type of food such as sugar can lead to more fibrosis if it’s consumed regularly, but bone broth is generally considered anti-inflammatory, possibly due to antioxidant activity, and has helpful nutrients other than collagen in it. Collagen wound dressings are used to help heal burn wounds, and they resist infection and increase healing, but this is a very different type of application.

It’s certainly worth looking at your diet and removing sugary drinks (soft drinks, alcohol, fruit juices) and foods, and reducing your consumption of food that is highly processed, including those made from flour since for most people these foods spike blood sugar levels dramatically and increase inflammation. Fruit with a lot of fructose, such as grapes and mangos, are worth limiting. But apples, pears, avocados and blueberries are beneficial. Don’t be afraid of moderate amounts of natural fats.

How important is the choice of surgeon to the outcome?