Influencing Factors And Radiologic Evaluation Of Scapular Dyskinesis In Shoulder Disorders

Objective Scapular dyskinesis,which is defined as the alteration of scapular position at rest and in movement is believed to be associated with the development of shoulder disorders.Yet,researches on scapular dyskinesis were still not deep enough at present,especially for the objective and feasible method to evaluate scapular dyskinesis in clinics.Therefore,the current study would investigate the incidence of scapular dyskinesis and influential factors associated with it in patients with shoulder disorders.Meanwhile,an application of using plain-film radiography to evaluate scapular dyskinesis would be explored.MethodsFirstly,eighty-one outpatients with unilateral shoulder disorders were included and received scapular dyskinesis evaluation with 4-types classification or "yes or no" method.Relevant clinical features for scapular dyskinesis were also evaluated and treated as independent variables for it.Logistic regression method was used to analyze independent risk factors for scapular dyskinesis.Secondly,eighty-seven individuals with unilateral shoulder pain were enrolled.Scapular dyskinesis for these participants were evaluated according to Kibler’s 4-types classification.After that,radiographs of bilateral scapulas were completed.Parameters including the coracoid upward shift distance(CUSD),the length of the scapular spine(LSS),the scapular upward rotation angle(SURA)were measured on these radiographs.Bilateral parameters differences were defined as d-CUSD,d-LSS and d-SURA respectively.Inter-rater and intra-rater reliability were calculated for all the measured parameters.Characteristics of radiologic parameters were compared with the 4 observational types to establish the validity.Receiver operating characteristic(ROC)curves were used to investigate the accuracy of bilateral parameters differences to evaluate different scapular dyskinesis.Results1.Of the eighty-seven patients,64.2%(52/81)had scapular dyskinesis and among which type Ⅲ accounts for the largest proportion 57.69%(30/52).2.Univariate analysis indicated that age,CMS,operation,rehabilitation were shown correlated significantly with scapular dyskinesis.However,the multivariate Logistic regression did select CMS,operation,rehabilitation as the independent risk factors for scapular dyskinesis.3.Intra-rater and inter-rater reliability were excellent for all the measured parameters on radiographs.4.CUSD in typeⅠscapular dyskinesis and LSS in type Ⅱscapular dyskinesis indicated statistically significant difference between the two sides(P=0.008,P=0.017).No significant difference was found in SURA between the two sides in type Ⅲ scapular dyskinesis(P=0.819).5.D-CUSD in typeⅠ scapular dyskinesis,and d-LSS in type Ⅱ scapular dyskinesis were increased as compared with those in the other types of scapular dyskinesis.With the area under the ROC being 0.757,0.738 for d-CUSD and d-LSS respectively,the corresponding cutoff values were d-CUSD,0.153 mm and d-LSS,1.517 mm.No significant difference was found in d-SURA among 4 observational types.Conclusion1.Patients with shoulder disorders had high incidence of scapular dyskinesis which correlated with shoulder function,clinical decision-making,rehabilitation for scapular dyskinesis.2.Plain-film radiography could be used as a feasible method to evaluate scapular dyskinesis at rest.D-CUSD and d-LSS can be used as the characteristic parameters for type Ⅰ and type Ⅱ scapular dyskinesis respectively.Type Ⅲ scapular dyskinesis requires further classification.