Neuromuscular Electrical Stimulation-Enhanced Physical Therapist Intervention for Functional Posterior Shoulder Instability (Type B1): A Multicenter Randomized Controlled Trial.

Recruitment was stopped early at 59 patients instead of the planned 66, reducing statistical power. Patients and clinicians could not be blinded to the treatment, which may have influenced subjective outcomes like satisfaction and reported improvement. There was a high dropout rate (10 patients excluded post-randomization, mostly for non-compliance), and follow-up rates dropped to 71.4% at one year. The physical therapists delivering the NMES intervention had no prior experience with the device, potentially affecting the consistency of delivery. The primary outcome was patient-reported; objective measures like strength and range of motion did not differ between groups, suggesting the mechanism may be neural rather than muscular.

The study was funded by the Deutsche Forschungsgemeinschaft, which had no role in the design, conduct, or reporting of the study. The NMES device used was the Neuralign System S by Alyve Medical, but no commercial funding from this company is reported.

Do not interpret the improvement in patient-reported scores as a cure for structural instability or a guarantee of pain reduction. The study found no significant difference in pain scores or shoulder strength between groups, and most patients in both arms remained able to voluntarily dislocate their shoulders. The benefit was primarily in functional perception and instability frequency, not in restoring normal anatomy or eliminating all symptoms.