Relationship of the Beighton Score to Specific Tests of Shoulder Joint Laxity

Abstract

Shoulder joint instability is a common problem, particularly amongst young active individuals. A frequent complication of shoulder instability is recurrence. This can be associated with significant morbidity and health care costs. It is desirable for clinicians to be able to predict which individuals are at higher risk of recurrence so that more aggressive treatment strategies (generally early surgery) may be employed in these cases. Shoulder joint laxity is one factor associated with increased rates of recurrent instability. It is currently uncertain whether measures of generalised joint laxity correlate with shoulder joint laxity or are significantly associated with the risk of shoulder instability. Part one of this research portfolio presents a background literature review of the assessment and management of shoulder instability with a focus on risk factors for recurrent instability. The evidence investigating the association of generalised joint laxity with shoulder joint laxity, and with the risk of primary and recurrent shoulder instability is also explored. This review found no evidence in the current literature that demonstrates an association between generalised joint laxity and specific measures of shoulder joint laxity. There are relatively few studies that have tested this association, and methodological issues limit the ability to make broad conclusions from this data. The literature is similarly limited exploring the association of generalised joint laxity with the risk of shoulder instability. Conflicting results are presented and methodological differences limit comparisons between these studies. Part two of this portfolio presents an original research project that investigates the relationship between generalised joint laxity, as defined by the Beighton score, and specific measures of shoulder joint laxity – glenohumeral external rotation, abduction and the sulcus sign, in 160 healthy young adult participants. This study demonstrated low sensitivity (range 0.4 – 0.48) and low positive predictive values (range 0.13 – 0.25) for a positive Beighton score as a predictor of abnormal shoulder laxity tests. When compared as continuous variables, the Beighton score had poor correlation with all measures of shoulder laxity performed. Part three of this portfolio consists of the study discussed above submitted as a journal article. This has been submitted to the Journal of Science and Medicine in Sport. Part four consists of a conference presentation made at the Sports Medicine New Zealand Conference in October 2017.