Joint hypermobility syndrome must be investigated in case of snapping scapula syndrome

Abstract

The snapping scapula syndrome (SSS) is an uncommon clinical picture responsible for significant discomfort. Various diagnoses are known but this problem is often non-specific. The joint hypermobility syndrome (JHS) has never been described in association with SSS. We report three cases of idiopathic SSS associated with JHS. Case 1: Female 18 yo, SSS right, JHS with a Beighton score of 9/9. Maximal passive external rotation of the shoulder > 85°. CT, MRI, Ultrasound and EMG: normal. Treatment with extended rehabilitation. Evolution unchanged. Case 2: Male 32 yo, SSS left, JHS with a Beighton score of 8/9. Maximal passive external rotation of the shoulder > 85°. CT, MRI and EMG: normal. Treatment with rehabilitation. Partially favorable evolution. Case 3: Male 45 yo, SSS right. Previous history of shoulder dislocation with spontaneous reduction. HJS with a Beighton score of 9/9. Maximal passive external rotation of the shoulder > 90°. MRI normal. No further follow-up data. SSS first described by Boinet in 1867 is a rare cause of shoulder pain. A “mechanical conflict” between the rib cage and the scapula is proposed. The conflict may be favoured by the presence of congenital or acquired bone abnormalities (exostosis, scapula fractures), muscle abnormalities (atrophy, tumors) or others like bursitis. In about 30% of the cases SSS no specific cause is found. CT, MRI and EMG are often required in the diagnostic process. Our 3 cases with SSS were only associated with positive criterion of JHS and shoulder passive external rotation more than 85°. Shoulder passive external rotation > 85° is a criteria of shoulder hyperlaxity but not of JHS. Only one patient was known for glenohumeral dislocation. We believe that JHS could be a factor favouring development of non-specific SSS, although the exact mechanism of SSS remains unclear. Treatment is based on rehabilitation often with poor results. We recommend searching a JHS as well as shoulder hyperlaxity in case of SSS.