[Monteggia's lesion in childhood--proposal for a new classification system]

The former classification systems have failed to provide an exact characterization of Monteggia's lesions (ML) in a growing skeleton. We studied the stability of both ulnar fracture and injury to the radio-humero-ulnar joint and our clinical findings fully warrant the proposal of a new classification system.

We carried out a retrospective study of 76 children, aged 2 to 15 years, treated for Monteggia's lesion in our department during 12 years, from 1990 till 2001.

X-ray images of all injured limbs were evaluated and each injury was categorized as stable, potentially unstable or unstable. This concerned both ulnar fractures and lesions affecting the radio-humero-ulnar joint. An assessment of the therapeutic method used was also included.

The final assessment of each injury involved the category of ulnar fracture and the category of radio-humero-ulnar joint lesion and produced three ML types, namely, stable, potentially unstable and unstable types. A stable ML type was found in 30 (39.5 %) patients and, in most of them, conservative treatment was sufficient. Osteosynthesis was required in only 6.7 % of the cases. A potentially unstable ML type was recorded in 27 (35.3 %) patients. Fifteen of these (55.6 %) underwent osteosynthesis because conservative treatment had failed. An unstable ML type was diagnosed in 19 (25 %) children and nearly all of them (89.5 %) had to undergo osteosynthesis.

The previous classification systems have been based on either anatomical aspects (direction of ulnar fragment displacement and proximal radius dislocation) or the type of ulnar fracture. In our view the characterization of each ML type in children involves the stability of ulnar fraction as well as the stability of injury to the radio-humero-ulnar joint.

Our classification allows us to predict the stability of each Monteggia's lesion and to choose an appropriate approach to its treatment.