Does Botulinum A Toxin Help With Pain From Rotator Cuff Arthropathy?

Inclusion Criteria: * Inclusion criteria The only eligibility criterion for participation in this study is that the patient is medically fit for an operation and diagnosed with symptomatic rotator cuff arthropathy. They must be able to give informed consent and have evidence of cuff arthropathy on plain radiographs of the affected shoulder. Exclusion Criteria: * Exclusion criteria Contra-indications to surgery (defined as severe cardiac impairment, e.g. heart or valve replacement, arrhythmia, previous myocardial infarction; severe respiratory impairment, e.g. chronic obstructive pulmonary disease, asthma that has required hospital admission; any other systemic medical condition that would produce a specific contraindication to a general anaesthetic). Evidence that the patient would be unable to adhere to trial procedures or complete questionnaires, such as dementia or intravenous drug abuse Note: If a recruited patient requires a contra-lateral shoulder botox injection during the trial period, this second shoulder cannot be included in the study since the result of this intervention would not be independent from the first intervention. Other exclusion criteria include: Previous fractures or dislocations of the shoulder. Previous surgery on the affected shoulder. Any neurological or medical condition resulting in spasticity