Inclusion Criteria:
1. Male or female subjects aged ≥ 45 years and ≤ 85 years.
2. Samilson Prieto Grade 1 to 3 of glenohumeral joint confirmed by a X-ray performed in the 6 months before the screening visit (or at the screening if not available in the past 6 months).
3. Patient suffering from glenohumeral arthrosis with chronic shoulder pain. Chronic shoulder pain is defined as follows:
* Patient who has persistent pain for a period of at least 6 months, but not exceeding 5 years; or
* Pain perceived by the patient with a frequency of at least 50% of the days in the month preceding the screening visit.
4. Presence of pain on movement, in the target shoulder, measured by VAS with a score \> 40 mm.
5. VAS for pain in the contralateral shoulder of at least 10 mm less than the target joint.
6. Willingness to discontinue oral and topical analgesics including NSAIDs if taken before study inclusion except for assumption of rescue medication (paracetamol) at a maximum dose of 6 tablets of 500 mg a day.
7. Patient willing to sign and able to understand the Informed Consent form.
8. If female of childbearing potential, must have a negative pregnancy test at screening and agree to use a reliable method of contraception throughout the investigation\*.
Note: To be considered of non-childbearing potential, females must be surgically sterile or postmenopausal for at least 1 year.
\*Highly effective birth control methods include: combined hormonal contraception (containing estrogen and progestogen) associated with inhibition of ovulation (oral, intravaginal, transdermal); progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable); intrauterine device (IUD); intrauterine hormone-releasing system (IUS); bilateral tubal occlusion; vasectomised partner; sexual abstinence.
Exclusion Criteria:
1. Presence, at clinical evaluation, of adhesive capsulitis.
2. Presence of rotator cuff injury (Massive Rotator Cuff Tears).
3. Signs, evident on X-ray of the shoulder, of recent fractures, intense loss of bone density and/or severe deformity.
4. Diagnosis of major calcium pyrophosphate dihydrate crystal deposition (CPPD) or shoulder chondrocalcinosis disease.
5. Presence of pathology of the cervical vertebrae (capable of altering the clinical evaluation) which, in the three months preceding the screening visit, was symptomatic and required active treatment.
6. Presence of any active musculoskeletal disease capable of altering the diagnosis/assessment of the shoulder with pain or presence of pain of any neurological aetiology and acute shoulder infection.
7. Presence of major surgery in arthroscopy in the shoulder under investigation in the 6 months prior to the screening and/or need to plan it.
8. Patient undergoing local radiotherapy for breast cancer.
9. Patient with rheumatic polymyalgia.
10. Patient with diabetes (Type 1 and Type 2 insulin-dependent).
11. Active skin cancer (except basal cell carcinoma) or history of skin cancer in the past two years.
12. Presence of infection and/or skin pathologies in the injection area.
13. Presence of severe gastrointestinal, renal, hepatic, pulmonary, cardiovascular, neurological, immunological or other pathologies that can interfere with the results of the investigation or inability of the patient to comply with the requirements of the investigation.
14. Known allergy or suspected allergic reaction to hyaluronate.
15. Pharmaceutical products taken orally and containing glucosamine and/or chondroitin sulfate and/or diacerin (eg. Chondrosulf, Structum 500, Dona, Viatril, Fisiodar, Artrodar etc.) in the month prior to the screening visit, unless the dosage was stable for the two months prior to the screening visit.
16. Intra-articular corticosteroid injections into the shoulder under investigation in the three months prior to the screening visit.
17. Taking oral corticosteroids in the month prior to the screening visit (only inhaled corticosteroids are allowed and chronic oral therapies with daily intake below 7,5 mg).
18. Subjects with a history of chronic or recurrent use of NSAIDs/analgesics/narcotics because of diseases different from GH OA.
19. Previous use of HA in the shoulder under investigation in the 6 months prior to the screening visit.
