Posteromedial rotatory instability of the elbow: What the radiologist needs to know

Zeid Al-Ani*, Andrew Wright, Matthew Ricks, Adam C. Watts

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

7 Citations (Scopus)


Varus posteromedial rotatory instability of the elbow joint is a relatively new subject described for the first time in 2003. It occurs secondary to axial loading of the elbow with varus force and internal rotation of the forearm. There is usually a specific pattern of osseous and soft tissue injuries that can be recognized on imaging. This includes an anteromedial coronoid fracture and avulsion of the lateral collateral ligament complex from its humeral attachment. Ulnar collateral ligament complex injury is also reported, particularly its posterior bundle which plays an important role in posteromedial elbow joint stability. There is high incidence of early osteoarthritis secondary to the resultant varus instability and increased contact pressure at the ulnohumeral joint. Surgical fixation of the coronoid fracture and ligamentous reconstruction maybe indicated to prevent this recurrent instability. The article reviews the key radiological features of posteromedial rotatory instability with multiple examples from different imaging modalities. The relevant anatomy of the elbow joint stabilising structures will be illustrated, in particular the coronoid process anatomy and the O'Driscoll classification for coronoid process fractures. Radiologists should be familiar with the imaging findings of posteromedial rotatory instability.

Original languageEnglish
Article number109819
Pages (from-to)109819
JournalEuropean Journal of Radiology
Early online date10 Jun 2021
Publication statusPublished - 10 Jun 2021


  • Biomechanical Phenomena
  • Collateral Ligaments
  • Elbow
  • Elbow Joint/diagnostic imaging
  • Humans
  • Joint Instability/diagnostic imaging
  • Radiologists
  • Range of Motion, Articular
  • Rotation


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