Risk Factors Associated with First Time and Recurrent Shoulder Instability: A Systematic Review.

Almost every included study was about dislocation or subluxation. Only two looked at less severe instability, so the review cannot say anything about the patients who feel loose or unstable without dislocating. The studies were too different from one another to combine, so there is no pooled estimate for any risk factor. Each finding rests on one study or a handful of studies. Quality was mixed. Five of the 39 studies scored under 5 out of 9, and some findings come from single studies, including one with only 45 people. Some of the strongest sport findings come from one military academy dataset in the United States. Fewer studies examined risk factors for females than for males. Three included studies did not separate first-time from recurrent instability. Odds ratios were missing from many studies and the authors could not calculate them all from the data given. The reference standard for diagnosing instability and the age norms differed from study to study.

The authors declare no conflicts of interest in the creation of this manuscript. No other declaration appears in the supplied text.

Do not treat these risk factors as confirmed or use them to screen patients. Most associations come from only one or two studies, quality scores ranged from 2 to 9 out of 9, and the studies were too different to pool into a single estimate. Many of the factors, such as sex, age and the shape of the shoulder socket, cannot be changed anyway.