Quality rating of studies included in the review according to the SIGN scale, which assesses the risk of bias and confounding present and the ability of the study to establish a causal relationship between the variables of interest and recurrent shoulder instability
| SIGN21 | Clear focused question | Selection bias | Selection bias | Performance bias | Attrition bias | Attrition bias | Detection bias | Detection bias | Detection bias | Detection bias | Detection bias | Detection bias | Confounding | CI | Limitation of bias | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Author | 1.1 | 1.2 | 1.3 | 1.4 | 1.5 | 1.6 | 1.7 | 1.8 | 1.9 | 1.1 | 1.11 | 1.12 | 1.13 | 1.14 | 2 | Rating† | Total‡ |
| teSlaa et al3 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | N | + | Acceptable | 5 | |||||
| Simonet and Cofield16 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | N | + | Acceptable | 5 | |||||
| Safran et al32 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 0 | Y | − | Low | 7 | |
| Sachs et al8 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | Y | + | High | 9 | |
| Robinson et al11 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | Y | + | High | 10 | |
| Kralinger et al15 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | N | − | Low | 4 | |||||
| Vermeiren et al31 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | N | − | Low | 2 | |||||
| Hoelen et al30 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | N | − | Low | 3 | |||||
| Salomonsson et al28 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | N | + | Acceptable | 7 | |||||
| Pevny et al29 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | N | − | Low | 5 |
*Grey shading indicates retrospective studies where it was not possible to evaluate criteria.
†Rating scales refer to how well the study has minimised the risk of bias or confounding and establish a causal relationship between the risk factor and recurrent instability. High-quality studies have little or no risk of bias, and the results from these studies are unlikely to change with further research. Acceptable quality studies have some associate risk of bias and the conclusions may change in light of further studies. Low-quality studies have significant flaws related to study design and the conclusions drawn from these studies are likely to change in the light of further studies.
‡Total scores can range from 0 to 13 with lower number representing increased risk of bias and higher numbers representing prospective cohort studies with minimal risk of bias.
N, no; SIGN, Scottish Intercollegiate Guidelines Network; Y, yes.