Radiological Measurement Of Acromioclavicular Joint And Its Significance

Objective:To measure the radiological parameters of normal acromioclavicular joint and acromioclavicular joint dislocation,and to provide reference for the diagnosis and treatment of acromioclavicular joint dislocation.Methods:From January 2009 to December 2016,anterioposterior(AP)view X-ray of normal shoulder in 1005 cases and acromioclavicular joint dislocation in 22 patients,10 Rockwood type III and 12 type V,were collected.Acromioclavicular distance and coracoclavicular distance were measured by measuring machine in the PACS system.Correlation analysis was peformed between two parameters.The correlation between each parameters and the age,the gender difference of each parameters,which from normal shoulder were analyzed.Results:For anterioposterior(AP)view X-ray of normal shoulder,coracoclavicular distance was(7.54±1.70)mm in males and(7.21±1.48)mm in females.There was significant difference between them(P<0.05).Acromioclavicular distance was(2.90±1.38)mm in males and(3.07±1.24)mm in females.There was no significant difference between them(P>0.05).The differences between age groups were significant for each parameters.Coracoclavicular distance showed negative correlation with age(r=-0.076,P<0.05),positive correlation with acromioclavicular distance(r=0.140,P<0.05).Acromioclavicular distance showed negative correlation with age(r=-0.308,P<0.05).For acromioclavicular joint dislocations,acromioclavicular distance is(12.07±1.28)mm in type Ⅲ and(15.13±4.72)mm in type V.Acromioclavicular distance is(8.28±2.15)mm in type Ⅲ and(12.78±4.03)mm in type V.Coracoclavicular distance showed positive correlation with acromioclavicular distance both in type Ⅲ(r=0.728,P=0.017)and in type V(r=0.829,P=0.001).Conclusions:The normal anatomic measurement standards of the acromioclavicular distance and coracoclavicular distance are established on anterioposterior(AP)view X-ray of shoulder.Acromioclavicular dislocation may exist when the acromioclavicular distance is more than 5mm so that contralateral radiographs should be taken.