. 2011 Jan 1;20(2):240–246. doi: 10.1007/s00586-010-1672-7

Table 3.

Demographic data of patients

Parameter	Group A	Group B	p Value
Age (years)	82.8 ± 2.7	67.2 ± 10.4	<0.001^a
Gender (men/women)	17/19	94/32	0.002^b
Symptom duration (months)	10.9 ± 16.9	22.2 ± 29.7	0.023^a
Follow-up (months)	15.9 ± 12.0	20.2 ± 12.7	0.017^a
JOA score
Preoperatively	8.4 ± 3.0	10.2 ± 2.6	0.002^a
Six months postoperatively	11.6 ± 2.7	13.1 ± 2.3	0.002^a
Final follow-up	11.4 ± 3.3	13.2 ± 3.3	0.004^a
Recovery ratio (%)
Six months postoperatively	37.5 ± 22.1	40.7 ± 29.0	0.552^a`
Final follow-up	36.0 ± 26.0	44.8 ± 55.6	0.300^a

Values for age, symptom duration, followup, Japanese Orthopaedic Association score, and recovery ratio are given as mean ± SD

JOA Japanese Orthopaedic Association

^aMann–Whitney U test

^bChi-square test