Table 1 Study characteristics and patient demographics of the included studies

Author (year)

Study design

LoE

No. of knees

No. of recurrences

Mean age of patients (years)

Gender

Follow-up (years)

Sillanpää 2009 [23]

Retrospective cohort study

III

42

9

20.0 (19–23)

53M

6.9

Seeley 2012 [24]

Retrospective cohort study

III

111

34

14.9 (11–18)

56M:45F

10

Zhang 2018 [25]

Prospective cohort study

III

147

46

20.0 (8–42)

67M:80F

5

Arendt 2018 [26]

Case-control study

III

145

64

17.9

64M:81F

2

Zhang 2019 [27]

Prospective cohort study

III

166

59

18.7 (8–42)

75M:91F

5