Background: Shoulder pain is the third most common musculoskeletal condition presenting to physicians or physiotherapists ) in primary healthcare after low back and neck pain being a significant cause of morbidity and functional disability in both working and general population. Despite the large group of individuals seeking for primary care services, about 50% of patients with shoulder pain still report persistent pain after 12-18 months. As a result, socio-economic burdens are considerable due to extensive use of heath care services, sickness absence, disability pension, and loss of productivity as well as, patient´s suffering.

Aims: the primary aim of this study was to evaluate what biopsychosocial factors predict a better and/or poor outcome in patients with Chronic shoulder pain. The secondary aim was to analyze the role of central sensitization in predicting a better and/or poor outcome in patients with Chronic shoulder pain.

Hypothesis:

1. A high level of physical inactivity, kinesiophobia, fear avoidance and pain catastrophizing and low level of self-efficacy will ease the perpetuation of Chronic shoulder pain.
2. The presence of central sensitization will predict a poor outcome in patients with chronic shoulder pain.

The present study will be a 24 months multi-center, double-blind, prospective, cohort study which will be carried out between April 2016 and March 2018. Subjects diagnosed of rotator cuff (RC) tendinopathy, adhesive capsulitis (AC), glenohumeral instability, superior labrum anterior to posterior (SLAP) lesion, and/or acromioclavicular pathology and fulfill the inclusion criteria will be asked for participating in the investigators study. Several questionnaires that will test the influence of different biopsychosocial factors and the presence of Central Sensitization will be administrated to these subjects. The outcomes will be assessed at baseline and 5 follow-ups (after 3, 6, 12, 18 and 24 months, t1-t6).

Subjects will attend for their routine clinical appointment. The examiners will carry out the clinical consultation according to usual practice. Subjects who fulfill the selection criteria will be asked whether they wish to be considered for trial participation. Examiners will inform subjects who are interested in participation. Ineligible subjects and those who do not wish to participate in the trial will receive normal clinical care delivered by clinicians according to the best clinical practice.

Anonymized age, gender and visual analogue scale (VAS)- verbal numeric rating scale (VNRS) for pain will be collected for those subjects who decline to take part in the project, in order to assess the external validity of the recruited sample of subjects.

Eligible patients who are interested in the trial will be asked to provide written informed consent to participate. The examiners will allocate the participants in an unique study group. Participants will then complete several questionnaires at baseline, 3, 6, 12, 18 and 24 months after the beginning of the study. A blinded examiner will deliver these questionnaires. Subsequent sessions will occur at the follow-up visits. Participants will be asked about any problems they had had during the previous months before following-up. There will be brief discussion about whether participants have subjected for any treatment (physical, pharmacological, injection and/or no treatment).

Inclusion Criteria:

1. Men / women aged between 18 and 70 years.
2. Patients suffering from shoulder pain, defined as pain presented or exacerbated by movements in the shoulder, pain intensity = 2 measured by a numerical scale with values from 0 to 10, meaning 0= no pain and 10= the worst pain, will be included in this study, among all these following shoulder pain conditions: (i) rotator cuff (RC) tendinopathy ; (ii) adhesive capsulitis (AC) ; (iii) glenohumeral instability ; (iv) SLAP lesion; (v) and/or acromioclavicular pathology. Subjects will not be required to undergo diagnostic imaging (i.e MRI) to diagnosis the pathology because of the recruitment will be carried out by clinical findings.
3. Duration of symptoms: greater than 3 months.

Exclusion Criteria:

1. Recent shoulder dislocation (1 year prior) and/or systemic diseases such as rheumatoid arthritis, osteoarthritis, fibromyalgia and/or polymyalgia rheumatica.
2. Shoulder pain considered to be originated in the cervical region and other traumas or if there is a neurological dysfunction (i.e multiple sclerosis), osteoporosis, hemophilia and / or cancer.
3. Inability to provide informed consent and/or complete written questionnaires.

Subjects between 18-70 years with chronic shoulder pain