Several Risk Factors Predict Instability After Anterior Shoulder Dislocation

By Will Boggs MD

May 11, 2015

NEW YORK (Reuters Health) - At least five factors increase the risk of recurrent instability after first-time traumatic anterior shoulder dislocations in adults, researchers from New Zealand report.

Rates of instability after first-time traumatic anterior shoulder dislocations range from 26% to 100% in published reports, and immediate surgical stabilization has been proposed for those at high risk of recurrent instability.

To develop and validate a predictive tool of recurrence that might eventually be used to identify which patients might require surgery, Margie Olds from Auckland University of Technology and colleagues undertook a systematic review and meta-analysis.

"To treat all these people as one homogenous group means that some will undergo unnecessary interventions for their problem," Olds, a clinical educator and PhD student, told Reuters Health by email.

Based on 10 studies, including 1,324 participants ranging in age from 15 to 96 years, the researchers identified five key risk factors in at least two good studies with strong evidence to support them.

The overall risk of recurrent instability one year after a first-time traumatic anterior shoulder dislocation was 39%, the team reports in the British Journal of Sports Medicine, online April 21.

Men had 3.18 times higher odds than women to have recurrent instability, and patients under 40 years old had more than 13 times higher odds than older individuals to have recurrent instability.

Time from the initial dislocation appeared to be important, with most episodes occurring within two years of the injury.

Other key factors influencing the risk of recurrent instability included hyperlaxity, which was associated with a 2.68-fold increase in odds, and greater tubercle fracture, which were tied to an 87% drop in the odds of recurrence.

"These are not risk factors which would decide surgical or non-surgical intervention," Olds noted. "These are risk factors that predict a recurrent event. How we deal with these risk factors needs to be a topic of further research."

The reduction method, type of immobilization, and period of immobilization did not appear to influence the rate of recurrent instability.

"Further research is required to establish a valid and reliable predictive tool weighted according to the strength of evidence of each variable," the researchers conclude. "This tool can then be used by healthcare professionals to predict customized risk rates for groups of people depending on their profile."

"It would be premature to conclude that those people who are at increased risk of recurrent instability are necessarily good candidates for surgical intervention, given the presence of confounders such as hypermobility in this group," they add.

Olds said that once she is able to separate patients into homogeneous groups, then she can investigate the success of interventions specific to those groups.


Br J Sports Med 2015.


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