Effects of Subscapularis Muscle Dry Needling on Clinical Symptom Improvement in People with Frozen Shoulder: A Randomized Controlled Trial Protocol

Background. Frozen shoulder is one of the major complaints among mid -aged and elderly populations and its initial symptoms are common with the initial symptoms of myofascial trigger points (MTrPs) of the subscapularis. Developing MTrPs of the subscapularis is prevalent and may aggravate frozen shoulder manifestations. Dry needling (DN), as a new approach, can deactivate these points. Therefore, the goal of this study is to investigate the impact of the subscapularis muscle DN on clinical symptom improvement in people with a frozen shoulder. Methods. This single -blinded (assessor) randomized controlled trial will randomly assign 40 participants into two groups: 1) conventional physical therapy (control) and 2) DN of the MTrP in the subscapularis muscle with conventional physical therapy (intervention). The outcome measures will be the range of motion of the glenohumeral joint, pain intensity, pain pressure threshold, and intensity of upper limb functional disability. Results. This study is the first study to determine if subscapularis DN has positive effects and will help to determine its effects on clinical symptoms improvement for people with a frozen shoulder. If deactivation of MTrPs in the subscapularis muscle via DN would have positive effects, it could be introduced as an adjunct treatment for these people. Conclusions. This study protocol is arranged to assess the impact of adding the DN technique to conventional physiotherapy in patients with a frozen shoulder. Study registration. This study is registered with registration code IRCT20200215046499N3 on the Iranian registry of the clinical trial (https://www. irct.ir/).