We tested the hypothesis that children who sustain a supracondylar fracture
have a greater range of elbow hyperextension than those with a fracture of
the distal radius.
Three observers made 358 measurements in 183 children (114 boys and 69 girl
s). There mere 119 fractures of the distal radius and 64 supracondylar frac
tures.
Initially, the group with a supracondylar fracture appeared to have extensi
on 1.7 degrees greater than that of the group with fracture of the distal r
adius. On average, there was a maximum variation of 3 degrees between obser
vers. After allowing for age, gender and observer, there was no significant
difference between the groups, Our study had greater than 80% power to det
ect a difference in hyperextension of 2 degrees at the 5% level with the ab
ove observer variability.
When age and gender are taken into account, any variation in the amount of
hyperextension at the elbow is not sufficient to explain the occurrence of
a supracondylar fracture.