Table 1.

Characteristics of included studies.

Study (author, year)	Design	Sample size	Age (years)	Follow-up (months)
Park et al., 201013	Retrospective	18	⩾ 22	⩾ 25
Kim et al., 201012	Retrospective	24	⩾ 20	⩾ 12
Ru et al., 201614	Retrospective	190	⩾ 19	⩾ 12