Table 2 Studies characteristics at different follow-up times
|  | Follow-up, months | Patients at 12 months of follow-up, n | Patients at 24 months of follow-up, n | Patients included in quantitative analysis at the maximum follow-up period, n | |
|---|---|---|---|---|---|
Conservative group | Surgical group | ||||
Kukkonen et al 2014, [29] | 3, 6, 12 | 110 | – | 55 | 55 |
Kukkonen et al 2015, [14] | 3, 6, 12, 24 | – | 109 | 55 | 54 |
Lambers-Heerspink et al 2015, [15] | 12 | 45 | – | 25 | 20 |
Moosmayer et al 2010, [12] | 6, 12 | 102 | – | 51 | 51 |
Moosmayer et al 2014, [30] | 6, 12, 24, 60 | – | 101 | 51 | 51 |