Subacromial impingement: influence of coracoacromial arch geometry an shoulder function

Objective. To find correlations between radiological coracoacromial arch ge ometry and shoulder function in patients with subacromial impingement syndr ome. Patients and methods. During a prospective study of the efficacy of ar throscopic subacromial decompression, we evaluated the function of the trea ted and contralateral shoulders using Constant's functional score and confr onted the results to several radiographic parameters reflecting coracoacrom ial arch geometry. Results. Constant's score values were tow (42 +/- 15) be cause of pain and a low level of activity. Males had significantly higher s cores than females. Constant's score was unaffected (P > 0.05) by patient a ge, the side, the level of activity, or the duration of symptoms, but was s ignificantly influenced by the orientation of the acromion with respect to the scapular spine and to the vertical scapular axis. The preoperative Cons tant's score was significantly higher in patients with a more horizontal ac romion (P = 0.01). A very tight correlation was found between the preoperat ive Constant's score and the angle between the acromion and scapular spine (P = 0.0003). Conclusion. Based on our results, we defined an open and a cl osed coracoacromial arch geometry. Coracoacromial arch geometry is correlat ed with shoulder function syndrome and can assist in the interpretation of rotator cuff impingement. Joint Bone Spine 2000; 67 : 305-9. (C) 2000 Editi ons scientifiques et medicales Elsevier SAS.