[Arthroscopic stabilisation of the shoulder. Risk factors for its failure]

Shoulder instability adversely affects the quality of life and restricts the functional capacity of the upper extremity involved. Today stabilisation surgery is almost always performed arthroscopically. The aim of this study was to present our experience with arthroscopic stabilisation of the shoulder and to identify risk factors responsible for its failure.

The group of 110 patients with recurrent anterior dislocation of the shoulder, who were treated between January 2007 and December 2010, consisted of 19 women and 91 men with an average age of 27 years (range, 14 to 56) at the time of surgery. Patients who had a concomitant tear of the rotator cuff or of the long head tendon of the biceps were excluded from the study. The minimum follow-up period was 2 years. The patients were evaluated for signs of clinical instability. Function was evaluated using WOSI, Constant-Murley and Rowe-Zarins. Statistical methods were used to assess factors leading to failed arthroscopic stabilisation.

At final follow-up, 17 patients (17 shoulders, 15.3%) had re-dislocation or subluxation of the joint treated. Age over 20 years reduced the probability of re-dislocation (odds ratio, OR=0.87; p=0.021) while the finding of an engaging Hill-Sachs lesion increased the risk of re-dislocation (OR=5.53; p=0.0028). The presence of a bony Bankart lesion had only a marginal effect on the probability of re-dislocation (p=0.0512). In stable shoulders the average pre-operative values improved to the final follow-up values as follows: WOSI index, 53.65 ± 5.6 to 94.8 ± 5.2 (p<0.0001); Constant-Murley score, 78.9 ± 6.1 to 95.6 ± 4.4 (p<0.0001); and Rowe-Zarins score, 53.3 ± 6.7 to 92.9 ± 7.8 (p<0.0001). No peri-operative complication was recorded.

Our study confirmed the role of 3D CT examination before arthroscopic stabilisation of the shoulder joint. The exact identification of bone injury and its extent is of prognostic importance. At the same time special attention should be paid to surgical and post-operative tactics in patients operated on before their 20 years of age. On the other hand, no risks were found to be associated with gender, sports activities, the number of previous dislocations, types of anchors, suture material or knot tying.

Arthroscopic stabilisation of the shoulder significantly relieves pain and improves shoulder function in 85% of the patients with anterior shoulder dislocation. The risk that this stabilisation surgery will fail increases with lower age of the patient and the presence of an engaging Hill-Sachs lesion.