Free joint body

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Classification according to ICD-10
M24.0- Free joint body
ICD-10 online (WHO version 2019)

A free joint body (Latin: corpus liberum , plural corpora libera ), also arthrolite ( ancient Greek ἄρθρον árthron , German 'joint' and λίθος lithos 'stone') or joint mouse (Latin mus articularis ) is made of cartilage , bone or the inner synovium ( Synovialis ) existing, freely movable body in a joint .

In the case of a so-called joint mouse, there is no connection whatsoever to the shedding earth - the joint mouse can move freely in the joint. Depending on the size and position of an articulated mouse, pinching and joint blockages can occur. The main symptom of entrapment, often accompanied by a sudden absolute joint lock, is also called the "mouse symptom". Joint mice can be clinically silent or make noises ( crepitation ) or cause spontaneous shooting pain.

If a joint body is not completely free, but is attached to the joint capsule or other structures by scar tissue, one speaks of a corpus pendulans . Joint bodies can become larger through the activity of chondroblasts or osteoblasts ; conversely, they can become smaller through the activity of osteoclasts or chondroclasts .


Possible causes of detachment are:

Joint surface defects caused by the joint mice are also known as the "mouse bed". The knee joint is particularly often affected. A joint mouse can be diagnosed by an x-ray , magnetic resonance imaging, or arthroscopy .


Symptomatic free joint bodies can be surgically removed. This is usually done via a minimally invasive operation ( arthroscopy ). If the cause of the free joint body is joint damage, this may also be treated during the arthroscopy.

If the cartilage is damaged, a cartilage-bone transplant ( osteochondral transplantation ) or a cartilage-bone drilling can be carried out in addition to drug treatment .

Physiotherapy or physiotherapy are used early after the operation .


  • Max Kappis : About the structure, growth and origin of joint mice . Deutsche Zeitschrift für Chirurgie 157 (1920), pp. 214–242.
  • Pschyrembel Clinical Dictionary, 259th edition Gruyter, 2002. ISBN 3-11-017213-5
  • Roche Lexicon Medicine, 5th edition Urban & Fischer Verlag, Munich 2003. ISBN 3-437-15150-9

Web links

Individual evidence

  1. ^ Pschyrembel (Medical Dictionary) , 266th edition, Berlin / Boston 2014, ISBN 9783110339970 , page 419
  2. ^ A b Hoffmann-La-Roche-Aktiengesellschaft (Grenzach-Wyhlen): Roche Lexicon Medicine , Elsevier Health Sciences, ISBN 3-437-15156-8 . P. 688 .
  3. ^ A b David A. Porter, Lew C. Schon: Baxter's The Foot and Ankle in Sport E-Book , Elsevier Health Sciences, 2007, ISBN 0-323-07021-3 . P. 370 .