Abstract
Objective
Shoulder instability is a common cause of morbidity amongst Professional Rugby Union players. This study explores whether the risk of shoulder dislocation is associated with innate shoulder laxity.
Methods
A randomised controlled study was completed in which all the Premiership Rugby Clubs in England were visited in 2006. 169 professional rugby players (mean age 25.1 years) with no history of instability in either shoulder were assessed and 46 injured players with one shoulder with a history of Bankart lesion or dislocation (mean age 27.5 years) also took part in this study. Shoulder laxity was measured by dynamic ultrasound. Anterior, posterior and inferior translations were measured in both shoulders for healthy players and the uninjured shoulder only for injured players.
Results
No significant difference between the non-dominant (anterior: mean 2.9±1.2mm; posterior: mean 5.1±1.8mm; inferior: mean 3.1±1.0mm) and dominant (anterior: mean 3.1±1.1mm; posterior: mean 4.9±1.6 mm; inferior: mean 2.9±1.0mm) shoulders in healthy players (P>0.05). The comparison between healthy shoulders (anterior: mean 3.0±1.2mm; posterior: mean 5.0±1.7mm; inferior: mean 3.0±1.0mm) from healthy players and the uninjured shoulder (anterior: mean 4.2±1.7mm; posterior: mean 6.2±3.0mm; inferior: mean 3.4±1.2mm) from injured players identified that players with unstable shoulders have a significantly higher shoulder translation in their normal shoulder than healthy players (P<0.05).
Conclusion
This is the first study looking at laxity and the risk of shoulder dislocations in sportsmen involved in a high contact sport. These results support the hypothesis that rugby players with ‘lax’ shoulders are more likely to sustain a dislocation or subluxation injury to one of these lax shoulders in their sport even if no symptom is presented.
