TORSIONAL STRENGTH OF PIN CONFIGURATIONS USED TO FIX SUPRACONDYLAR FRACTURES OF THE HUMERUS IN CHILDREN

Supracondylar fractures of the humerus in children are commonly treated with closed reduction and percutaneous pin fixation. Using an adult human cadaver model, we measured the resistance to internal rotation of the distal fragment of simulated supracondylar fractures, fixed with four different configurations of pins. The maximum stability was provided by two crossed pins placed from the medial and lateral condyles. In comparison, the torque required to produce 10 degrees of rotation averaged 37 per cent less with use of two lateral parallel pins and 80 per cent less with use of two lateral crossed pins (p < 0.05 for both). The average torque required to produce 10 degrees of rotation with use of three lateral pins was 25 per cent less than with use of two medial and lateral crossed pins, although the difference was not significant. CLINICAL RELEVANCE: Because two crossed pins placed from the medial and lateral condyles provided the greatest resistance to gross rotational displacement, this method may be preferable for most fractures. However, the alternative of three lateral pins, or even two lateral parallel pins, may be considered when marked swelling of the elbow makes safe placement of a medial pin difficult. Fixation with two lateral crossed pins should be avoided.