The Effect of Arthroscopic Subacromial Decompression in Patients Who Are Non-responders to Non-operative Treatment.

In addition to the glenohumeral athroscopy a lateral portal will be used to access the subacromial space. The subacromial space will be decompressed with removal of inflamed bursal tissue and acromioclavicular osteophytes, release of the coracoacromial ligament, and, if deemed necessary by the surgeon, acromioplasty performed ad modum Caspari.

Glenohumeral arthroscopy is performed as a standard investigational procedure. The patient is put under general anesthesia and positioned in the 'beach chair position'. An anteriorsuperior portal and a posterior mid-glenoid portal are used as entry to the joint. The following structures are investigated as a minimum: the articular surface of the humeral head and the glenoid, labrum, the long biceps tendon and its attachment at the superior labrum, the undersurface of the supraspinatus and the infraspinatus tendon, the subscapularis tendon and the glenohumeral ligaments. To allow for the best possible blinding a skin incision (mimicking the one used for arthroscopic subacromial decompression) is performed on the lateral side of the shoulder of the participants in the control group. The obturator is introduced in the subcutaneous tissue and a slight circular release is performed. The deltoid fascia is not perforated and the subacromial space is not entered.