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Kocher-Lorenz fracture

Case contributed by Dr Benoudina Samir


Fall on an outstretched left arm. Pain, swelling, and restriction of motion of the elbow. No neurovascular deficit.

Patient Data

Age: 40 years
Gender: Male

The lateral film demonstrates :

  • Joint effusion
  • Articular cartilage separation (coronal shear fracture) with very little subchondral bone attached, with anterior displacement
  • A minimally displaced radial head fracture

Features consistent with a Kocher-Lorenz fracture (type II capitellum fracture, according to Bryan and Morrey classification with McKee modification), with an undisplaced fracture through the lateral aspect of the radial head.

Annotated image
  • yellow arrow: type II capitellum fracture (Kocher-Lorenz fracture)
  • blue arrow: type I radial head fracture

Case Discussion

Concomitant capitellar and radial head fractures occur with falls on an outstretched hand with the elbow extended or partially flexed. This association of injuries is frequently missed leading to elbow stiffness, chronic pain, intra-articular loose bodies, malunion, and nonunion.

According to  Bryan and Morrey classification (with McKee modification), there are four types of capitellum fractures:

  • type I (Hahn-Steinthal): large fragment containing substantial subchondral bone
  • type II (Kocher-Lorenz): sleeve fracture with minimal bone
  • type III: comminuted fracture
  • type IV: fracture including a major portion of the trochlea

In this case, it is a Kocher-Lorenz capitellum fracture (type II) and type I radial head fracture according to the Mason classification.

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Case information

rID: 75974
Published: 10th Apr 2020
Last edited: 10th Nov 2020
Inclusion in quiz mode: Included
Institution: Clinique Les Babors - SETIF - Algeria

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