Purpose: The aim of study is to compare the kinematic parameters and activity pattern of muscles around the glenohumeral joint in multidirectional instability (MDI) treated by only physiotherapy and by capsular shift and physiotherapy, before and after treatment.

Materilal and method: The study was carried out on 32 patients with MDI treated with only physiotherapy (29 patients after 2 years, and 21 patients after 4 years), 19 patients with MDI treated by capsular shift and physiotherapy (19 patients after 2 and 4 years), and 50 healthy subjects as control group. The investigated kinematic parameters were the range of the humeral elevation (HE) in the scapular plane, the scapulothoracal and glenohumeral angle, the scapulothoracal (ST) and glenohumeral (GH) rhytms, and relative displacement between the rotation centers of the humerus and the scapula. The muscle activity was modeled by the on-off pattern of muscles around the shoulder.

Results: Before treatment the increased relative displacement between the rotation centers of the scapula and the humerus and different ST and GH rhythms were observed in MDI patients. The physiotherapy strengthened the rotator cuff, biceps brachii, triceps brachii, deltoid muscle, but ST and GH rhytms remained monolinear. Capsular shift and physiotherapy resulted bilinear ST and GH rhytms and normal relative displacement between the rotation center of scapula and humerus was restored. After surgery and physiotherapy the activity pattern of muscles around the shoulder was almost normal.

Conclusion: The signifi cant alterations in kinematic parameters in MDI patients cannot be restored by physiotherapy only. After the capsular shift and postoperative physiotherapy the bilinear
ST and GH rhytm (angulation at 60 degree), the normal relative displacement between the rotation centers of scapula and humerus and the normal muscular activity pattern can be restored.

DOI: 10.17489/biohun/2010/1/20