Key points

A knee with arthrofibrosis may feel painful and stiff, and have limited range of motion


  • Exercise very carefully in the pain-free zone. Exercising other parts of the body is the safest option.
  • Elevate and ice if your joint is swollen, hot or red.
  • Passive stretching/Continuous Passive Motion – should be used carefully every day to maintain and increase range of motion.
  • Tests:
    • Infection – Culture and molecular test of synovial fluid withdrawn by needle aspiration.
    • Inflammatory cytokines – blood test, can also test synovial fluid.
    • Autoimmune diseases and other – blood test.
    • Nutritional status – blood test for iron, Vitamin D, potassium etc, and iodine in urine.
  • Diet – caloric restriction (fasting) and diets high in vegetables, fruit, nuts and legumes (eg the Mediterranean diet) are known to reduce inflammation. In general, a low sugar, high fibre diet is recommended. See
  • Supplements – take nutrients shown to be deficient (eg Vit D). Avmacol and fish oil have anti-inflammatory properties. Note: use these as appropriate for an individual’s medical condition and medications, consult a doctor.
  • Anti-inflammatory medications. Note: use these as appropriate for an individual’s medical condition and medications, consult a doctor.
    • Metformin
    • Low dose aspirin
    • TNF-a antibodies (eg Simponi, Humira)
    • Anakinra (IL-1 antagonist)
    • Corticosteroids
    • Others – Losartan, hydroxychloroquine etc
  • Stress reduction and meditation regularly.
A shoulder with arthrofibrosis (Frozen Shoulder) may be painful to rotate and/or lift and have limited range of motion.


  • “Push through the pain” while exercising or stretching.
  • Have poor sleep hygiene and untreated sleep apnoea – good sleep is essential for proper immune system functioning.
  • Permit anxiety and stress. Stress has a powerful effect on the immune system and increases inflammation.
  • Have untreated gum disease – good mouth hygiene is important. Bleeding gums allow bacteria into the bloodstream, and these can travel to joints and remain there, creating inflammation.
  • Continue with any activity that upsets the joint (pain, swelling, heat).
  • Continue with long term non-steroidal anti-inflammatory medications (NSAIDS).

Go Deeper

Don’t “Push through the pain”, be extremely careful with exercise

Each individual with arthrofibrosis has a level of exercise that their affected joint can tolerate. Without the assistance of anti-inflammatory medications exercise tolerance may be minimal. For example, for some people with active arthrofibrosis of the knee even standing is painful and increases inflammation. For those with residual (stiff but pain-free) arthrofibrosis exercise tolerance may not be significantly limited.

The “take-home” message is to exercise the affected limb according to your abilities – do not compare yourself to others, or to your previous abilities. Continuing to exercise beyond the pain-free zone, either in intensity or duration, increases inflammation and causes damage that can be permanent.

However, other parts of your body that aren’t inflamed can typically be exercised without a problem, and this likely has beneficial effects on health and wellbeing.

For more on exercise, see “Arthrofibrosis and Exercise” under “About Arthrofibrosis”.

Elevate and Ice

If the joint is warm, puffy or red, icing and elevating is recommended. Raising the joint to level with, or above, the heart and icing for 20 minutes reduces inflammation and tissue damage, and promotes healing. This is done as often as needed over the course of each day.

Care needs to be taken not to cold-burn the skin, and at least one layer of cloth must be placed between the ice pack and the skin. Ice machines can be useful, and frozen clay or gel packs are also useful as these are pliable and will bend around the joint.

Passive Stretching and Continuous Passive Motion (CPM)

Passive stretching devices, particularly CPM, are important for maintaining joint mobility and range of motion (ROM), and can slowly increase ROM if used daily1. CPM can also be useful in reducing inflammation2.

CPM has been controversial with studies citing little evidence of efficacy3. However, these studies were not about treating arthrofibrosis, they were conducted on the general surgical population undergoing their first joint replacement without complications3. The great majority of people who have surgery do not develop arthrofibrosis. Therefore, any positive response to CPM from the small number of people who would have developed post-surgical arthrofibrosis was diluted in the pooled result4. More research is needed into the efficacy of CPM for treating people with arthrofibrosis3,4.

IMPORTANT: Care must be taken not to force the joint beyond its ability to stretch. The joint should only be bent or straightened to the point at which it is mildly uncomfortable – think of the discomfit of pushing your finger backwards and stretching it. Pushing further than discomfit risks tearing tissue, and that is a major setback.

Each session should begin in the safe zone. When the joint is comfortable moving through the range of motion the limits of bend and extension are increased 1 degree. This process is repeated until the maximum safe limits for that session are reached. ROM settings should only ever be increased by 1 degree at a time, never more than that. In our opinion, legs should not be strapped in.

During periods of little to no movement the collagen fibres in the connective tissue in muscles, tendons and ligaments contracts and the structure of the fibres changes, making them less flexible. This even occurs overnight5, and it occurs in all people to some extent. This is the reason that stretching first thing in the morning feels pleasurable.

When tissues are inflamed the contraction process is greatly increased due to the presence of the special cells that make scar tissue, called myofibroblasts. This contraction can create a severe lack of ROM, particularly in the morning and after periods of immobilisation. For more information on tissue contraction, see


Passive stretching is therefore likely to be most beneficial early in the morning. It gently stretches collagen fibres out, permitting greater ROM and thereby avoiding tearing during daily use. Mobilisation and stretching also flushes out toxins (inflammatory cytokines, dead cells etc) and rehydrates connective tissue and membranes so that they slide against each other properly and do not form adhesions.

In the US there are several hand-operated stretching devices available for the treatment of knees, but in our opinion motorised, computer controlled CPMs do a better job since they have precise 1o incremental control of ROM and there is less likelihood of accidental tears. In addition, a CPM used correctly takes a joint through the full range of motion many times during a session, so there are greater benefits from mobilisation.

It is our view that CPMs should be used often, at least twice a day in the early stages of arthrofibrosis. Some people sleep with the affected limb in a CPM, and this may be necessary in the early healing stages if there is aggressive arthrofibrosis. The amount of inflammation and aggressive healing influences the treatment time needed for each session, and this varies between individuals.

Computer controlled CPMs have an emergency button to quickly lower the amount of bend, and for safety the person being treated should always hold the controller and know how to operate it. The joint should be flexed through the comfortable range of motion and held the maximum position for 2 to 10 seconds to permit stretching of tissues.

Optiflex describes their program for knee CPMs “When the carriage reaches the Programmed (maximum) Flexion Angle, it will oscillate between the Programmed Flexion Angle and 10° less than the flexion angle, three times. On the third oscillation cycle, the carriage will hold at the flexion angle for the Programmed Extension/Flexion Delay Time”.

Good reconditioned second-hand CPMs can sometimes be purchased on Ebay (ex-hospital) and these can be a good option. Always look for computer controlled CPMs.

CPM References

  1. Aspinall, S. K. et al. Medical stretching devices are effective in the treatment of knee arthrofibrosis: A systematic review. J Orthop Translat27, 119-131, doi:10.1016/ (2021).
  2. Ferretti, M. et al. Anti-inflammatory effects of continuous passive motion on meniscal fibrocartilage. J. Orthop. Res. 23, 1165–1171 (2005).
  3. Chaudhry, H. & Bhandari, M. Cochrane in CORR ((R)): Continuous passive motion following total knee arthroplasty in people with arthritis (Review). Clin Orthop Relat Res 473, 3348-3354, doi:10.1007/s11999-015-4528-y (2015).
  4. Usher, K.M, S. Zhu, G. Mavropalias, J.A. Carrino, J. Zhao, and J. Xu (2019) Pathological mechanisms and therapeutic outlooks for arthrofibrosis. Bone Research 7:9
  5. Corcoran, P. Use it or lose it –the hazards of bed rest and inactivity- adding life to years. Western J. Med. 154, 536-538 (1991).


Infection: In cases of prior injury or surgical procedure it is important to test the synovial fluid in the affected joint for infection. Synovial fluid is extracted by needle aspiration of the joint, often after flushing with sterile saline solution. Infections tests are particularly important for people with a prosthesis or metal “hardware” that microorganisms can adhere to.

Chronic low-grade infections often do not have the classic symptoms of redness, heat and swelling that are typical of acute infections, and may be missed by surgeons. This, together with the need for highly sensitive infection tests, means that chronic low-grade infections are notoriously difficult to diagnose. The traditional culture test is not adequately sensitive.

In addition to a culture test a molecular test called a PCR and sequencing should be performed on the synovial fluid. This test is more sensitive for identifying low numbers of bacteria that may be present in the joint. Next generation sequencing is a more advanced and powerful molecular test that is capable of identifying multiple microorganisms if these are present. 

Identification of microorganisms using molecular techniques permits the appropriate antibiotic (or other medication) to be prescribed.

It is also necessary to rule out infection prior to taking anti-inflammatory medications, since these increase the risk of infection.

Inflammatory cytokines:  Inflammatory cytokines are proteins the body makes that play an important role in inflammation. Testing levels of systemic inflammatory cytokines, including IL-1, IL-6, TNF-a is important for understanding an individual’s immune status, and which treatments are appropriate. Companies that offer these tests include ARUP Laboratories and the Mayo Institute in the US, and NutriPATH in Australia. Abnormal test results may indicate that a rheumatologist should be consulted.