Table 2 .

Number of orthopedic surgeries before and after 9 years of age

	Younger than 9 years old					Older than 9 years old
	Ankle/foot	Knee	Hip	Spine	Fractures	Ankle/foot	Knee	Hip	Spine	Fractures
Sacral	6	0	0	0	0	10	1	0	0	0
Lower lumbar	35	0	18	1	1	31	3	8	5	3
Upper lumbar	23	2	31	0	0	9	0	5	7	2
Thoracic	6	1	0	17	0	3	0	2	15	2
P-value (Fisher– Freeman–Halton test) before and after 9 years old	0.1059	0.0857	0.0121	0.0089	0.4859	0.1059	0.0857	0.0121	0.0089	0.4859