Arthrofibrosis of the knee is a complication of injury or surgery where an excessive scar tissue response leads to painful restriction of knee motion. Page updated March 2024 by Dr Sheila Strover (Clinical Editor)
This illustration shows a knee that has been cut open vertically. Normally the soft tissue folds are lubricated and allow easy bending and straightening of the knee. The kneecap (patella) will be quite mobile.
Inflammation in the soft tissues above and below the kneecap triggers sticky adhesions gluing up the tissue folds
In arthrofibrosis these adhesions mature into scar tissue, which contracts and locks up the joint
Then adhesions develop start to stick down the soft tissue folds of the suprapatellar pouch, posterior capsule and anterior interval underneath the tendon. This may result in flexion loss, extension loss or both. Matured scar tissue then contracts, closing the important spaces that normally allow movement, and pulling the kneecap right down (patella baja or infera), where every movement is painful.
Quick linksDefinitions:
End of linksSignificant surgery might include a multiligament reconstruction or total knee replacement, or there might have been a bad knee injury where the joint has had to be immobilised. A particular trigger is a large bleed inside the knee (haemarthrosis), with painful swelling of the joint.
Because true arthrofibrosis is not common, the importance of the symptoms may not be recognised and managed early during the physiotherapy phase. By the time the management team recognise that this process has been triggered, it may be difficult to manage.
Quick links'Pushing through the pain' may simply make things much worse, triggering more inflammation and swelling, and further limiting range of motion. The joint may feel warm to the touch.
Quick linksThe abnormal position of the patella may result in considerable pain when trying to walk, and the knee may be most comfortable in a slightly bent position.
Peer-reviewed papersQuote from peer-reviewed paper:
Citation: Usher KM, Zhu S, Mavropalias G, Carrino JA, Zhao J, Xu J. Pathological mechanisms and therapeutic outlooks for arthrofibrosis. Bone Res. 2019 Mar 26;7:9. doi: 10.1038/s41413-019-0047-x. PMID: 30937213; PMCID: PMC6433953.
Manipulation under anaesthesia may help to break adhesions before they become permanent scar tissue. Advanced arthrofibrosis with marked knee stiffness may need surgical lysis of adhesions to regain range of motion, in combination with specialist pain management and physiotherapy.
Peer-reviewed papersQuote from peer-reviewed paper:
Citation: Fahlbusch H, Krivec L, Müller S, Reiter A, Frosch KH, Krause M. Arthrofibrosis is a common but poorly defined complication in multiligament knee injuries: a systematic review. Arch Orthop Trauma Surg. 2023 Aug;143(8):5117-5132. doi: 10.1007/s00402-022-04730-9. Epub 2022 Dec 15. PMID: 36520199; PMCID: PMC10374851.
Definitions:
End of linksHundreds of patients' discussions about their experiences with arthrofibrosis.
A long chat about members' experiences with knee arthrofibrosis.
Several patients compare benchmarks for recovery from knee arthrofibrosis.
Patients collecting names of specialists with an interest in arthrofibrosis.