Reverse or Anatomical replacement for Painful Shoulder Osteoarthritis, Differences between Interventions (RAPSODI-UK)

INTERVENTION: Eligible and consenting patients will be randomly allocated to either anatomical total shoulder replacement (aTSR) or reverse total shoulder replacement (rTSR). Only non‐augmented replacements will be used. Therefore, patient specific implants that are custom made to an individual’s anatomical specifications will not be allowed. Intervention: For the rTSR, the arrangement of the ball and socket component parts are reversed making use of the deltoid muscle for movement of the arm: it does not rely on an intact or functioning rotator cuff. Comparator: The aTSR is a conventional shoulder replacement which mimics the natural ball and socket structure of the joint and relies on the presence of an intact rotator cuff for useful range of movement. The choice of implant will depend on local practice at recruiting sites but will include any anatomical shoulder implant from any manufacturer licensed for use in the UK implanted using techniques consistent with manufacturer instructions. Randomisation: Allocation will be 1:1, using random permuted blocks of random block size, stratified by age (60‐69; 70+) as a surrogate of deteriorating shoulder rotator cuff function. The allocation schedule will be generated by a trial statistician, otherwise not involved in the recruitment or randomisation of participants. It will be implemented using a secure web‐based randomisation service managed by York Trials Unit (YTU), ensuring allocation concealment. The research team at the site will confirm patient eligibility and consent and access the online service to perform the randomisation ideally two weeks before surgery but no earlier than the pre‐operative clinic to confirm the patient is fit for surgery. CONDITION: Painful osteoarthritis of the shoulder joint ; Musculoskeletal Diseases PRIMARY OUTCOME: Patient‐reported shoulder pain and function measured using combined Shoulder Pain and Disability Index (SPADI) score at 24 months SECONDARY OUTCOME: 1. Pain and function measured using total SPADI score at 3, 6, 12, 18, and 24 months ; 2. Quality of life measured using individual subscales of pain and disability from SPADI, Oxford Shoulder Score (OSS), and EuroQol 5‐dimension 5‐level (EQ‐5D‐5L) questionnaires at 3, 6, 12, 18 (SPADI only) and 24 months; 3. Resource use measured using a patient‐reported questionnaire at 3, 6, 12, and 24 months ; 4. Re‐operations and complications measured from medical records at 3, 6, 12, and 24 months ; 5. Objective assessments using shoulder range of movement and strength and global shoulder score at 24 months; 6. Revisions and mortality measured from medical records at 24 months. INCLUSION CRITERIA: 1. Aged =60 years 2. Diagnosis of painful osteoarthritis of the glenohumeral joint using routine radiographs not controlled by previous interventions 3. An intact rotator cuff determined by pre‐operative advanced imaging (Ultrasound, MRI, or CT) 4. Minimal glenoid erosion determined by pre‐operative CT or other imaging in whom a non‐augmented replacement is appropriate 5. Able to give informed consent