Table 2.

Demographics of the study groups

	n	Gender distribution (female: male) (n) (percent of total)	Age in years at surgery (mean, range)	Right: left hip (n) (percent of total)
Included total	368	331:37 (89.9%:10.1%)	27.4 (10–48)	221:147 (60.1%:39.9%)
Borderline group	196	183:13 (93.4%:6.6%)	27.6 (14–46)	106:90 (54.1%:45.9%)
Dysplasia group	172	148:24 (86.0%:14.0%)	27.2 (10–48)	115:57 (66.9%:33.1%)

Interestingly, in the dysplasia group, two-thirds of the symptomatic hips needing TPO were right hips. We have no conclusive explanation for this unexpected distribution