Glenohumeral Re-centering During Closed Kinetic Chain for Shoulder Physiotherapy. A Prospective and Randomized Study.

Shoulder impingement accounts for 44 to 65% of shoulder complaints during physician visits. Shoulder impingement has been classified into two main categories: structural and functional. The structural impingement can be caused by narrowing of the subacromial space resulting from a reduction in the space due to bony growth or soft-tissue inflammation. The functional impingement or superior migration of the humeral head can be caused by weakness and/or muscle imbalance. It is possible that some subacromial impingement results from a combination of both structural and functional factors. Subacromial impingement occurs when the structures in the SAS (rotator cuff, biceps tendon long head, and subacromial bursa) become compressed and inflamed under the coracoacromial ligament. The suprasinatus tendon in particular is at highest risk for irritation and subsequent injury because it is the most likely to contact the acromion when the humerus is abducted to 90° and internally rotated 45°.

The clinical impairment is not always the same and varies from a painful shoulder with correct range of motion to a pseudoparalysis shoulder. The first treatment of this subacromial impingement is always non surgical and consists in relative resting, painkillers and/or non-steroidal anti-inflammatory drugs (NSAD) and physiotherapy. The aim of this treatment is to relieve pain and to restore the mobility and a good function of the shoulder.

There is no consensus about the physiotherapy protocol for the treatment of the shoulder impingement. In France, the most used physiotherapy protocol uses the strengthening of the muscles which stabilize the scapula (rhomboide muscles, trapezius and serratus anterior) and which lower the humerus (pectoralis major, latissimus dorsi and teres major). The aim of this approach is to augment the subacromial space in order to decrease the inflammation of the rotator cuff tendons and the associated pain. A technique of Dynamic Humeral Centering (DHC) uses a new method of glenohumeral centering in closed kinetic chain has been described ("3C Concept" for Centering in a Closed Chain). Dynamic humeral centring (DHC) is a modality of physiotherapy that aims to prevent subacromial impingement of rotator cuff tendons. In order to simplify and to improve its reliability, a special device called Scapuleo® has been developed. The aim of this device is to help the physiotherapist to realize simultaneously a subacromial decompression, a specific strengthening of the rotator cuff muscles and an optimal activation of the lower trapezius and the anterior serratus.

Our hypothesis was that the DHC was not inferior to the conventional physiotherapy protocol for the medical treatment of the subacromial impingement.

We proposed a prospective and randomized study. All the patients treated in our department for simple tendinopathy of the rotator cuff or partial thickness tear were included in this study after signed consent. The physiotherapy protocol consisted in 20 sessions of either "Conventional program" (Control group) or "Dynamic Humeral Centering" (Study group). The clinical evaluation included the range of motion measurement, Constant Score, Quick-DASH and Oxford Shoulder Score at 3 months and 6 months. Patients were blinded to the study hypothesis. The assessor of all outcomes was blinded to the interventions.