Table IV.

The statistical properties of the optimal RUSHU cut-off values for predicting nonunion in the FISH trial cohort at six and 12 weeks.

Variable	Nonunion	Union	Predictive value
RUSHU cut-off at 6 weeks (n = 66)
8 points or less (n = 20)	13	7	PPV = 0.65
9 points or more (n = 46)	3	43	NPV = 0.94
	Sensitivity = 0.81	Specificity = 0.86	p < 0.001*
RUSHU cut-off at 12 weeks (n = 68)
10 points or less (n = 22)	17	5	PPV = 0.77
11 points or more (n = 46)	1	45	NPV = 0.98
	Sensitivity = 0.94	Specificity = 0.90	p < 0.001*

^*Chi-squared test; statistically significant.

FISH, Finnish Shaft of the Humerus; NPV, negative predictive value (probability of union if RUSHU is above set threshold); PPV, positive predictive value (probability of nonunion if RUSHU is below set threshold); RUSHU, Radiographic Union Score for HUmeral Fractures.