Proprioception and EMG pattern after capsulolabral reconstruction in shoulder instability: a clinical and experimental study

The anterior capsulolabral reconstruction according to JOBE [13] is a modification of the Bankart operation. The capsular shift is performed via a subscapularis-split approach avoiding any incision into the musculature. A total of 43 patients with posttraumatic, chronic anterior shoulder instability underwent surgery. All patients had at least four dislocations preoperatively. Thirty-five patients were examined after an average of 3.7 ± 1.4 years. Twenty-nine (82.9%) of these patients were free of pain, with functional assessment showing a mean external rotation deficit of 4.1° ± 2.9° without any further movement restrictions. On average, a Rowe-Score of 86.1 ± 12.4 points and an ASES-Score of 93.3 ± 8.4 were achieved. The reluxation rate was 7.7%. The study demonstrated that despite the good clinical results, only 69% of patients were able to return to their previous sports activity level. This special problem is in agreement with other similar studies [4, 18] so that this relevant fact was further addressed by determination of proprioception and electromyographic muscle activity. Postoperatively, in contrast to other studies [1, 21, 24], a persisting proprioceptive deficit as well as an altered EMG pattern was found together with a significant reduction in activity of the deltoideus muscle on the operated side. These results may explain the problem to achieve complete restitution of the function of the shoulder joint after capsulolabral reconstruction.