The shoulder-pacemaker treatment for functional posterior shoulder instability

Abstract

Functional posterior shoulder instability (Polar Type III) can lead to posterior subluxation and/or dislocation during shoulder movement. Disturbed activation of external rotators and periscapular muscles generating a force imbalance in the shoulder can result in instability, weakness and pain as the leading symptoms patients present. Recommended conservative treatment is often ineffective, alternative surgical treatment may diminish function even further and aggravate pain. The implementation of the Shoulder-Pacemaker was evaluated in a prospective clinical trial. Patients suffering from functional posterior shoulder instability refractory to previous treatment options should regain glenohumeral shoulder stability after our conservative therapeutic training regime with the Shoulder-Pacemaker. 19 cases with therapy-resistant functional posterior shoulder instability had been included in the Shoulder-Pacemaker therapy-concept. Previously all patients were treated unsuccessfully with at least 3 months of regular physiotherapy. Failed surgical stabilization attempts were not an exclusion criterion. Prior to treatment, a fluoroscopy was performed for diagnosis assurance as well as the evaluation of current MR-Imaging for excluding structural defects. The Shoulder-Pacemaker therapy consisted of a 3- to 6- weeks conservative treatment regime with electric muscle stimulation and regular physiotherapy. For longitudinal evaluation of shoulder function, a specifically developed questionnaire including SSV, ROWE and WOSI score was assessed. After treatment, all patients were very satisfied and fully recommended the Shoulder-Pacemaker therapy. All cases improved in all scores assessed and patients had been able to return to physically demanding and even sporting activities. Patients with completed 3-month follow-up achieved a Rowe score of 92 ± 14, SSV of 95 ± 6%, and WOSI score of 372 ± 181 [Figure 1]. In 2 out of 19 cases the training was not completed because of lack of compliance. No complications were observed. The Shoulder-Pacemaker therapy is a very effective treatment option in patients with functional posterior shoulder instability. Even if previous conservative or surgical stabilization attempts failed, the Shoulder-Pacemaker therapy successfully re-established glenohumeral stability and seems to have a long-lasting effect. Because of the short time of follow up, these results remain preliminary.