Inclusion Criteria:  ASA I-III Age between 18 and 80 Proximal humeral fracture  Exclusion Criteria:  Surgical exclusion criteria: Revision surgery 4 parts fractures Unable to attend rehabilitation Preexisting shoulder problems Abbreviated Mental Test Score (AMT score) < 8 Allergy to amide local anaesthetics, paracetamol, non-steroidal anti-inflammatory drugs (NSAIDS), opioids Respiratory Disease with limited respiratory reserve Cardiac Disease: Any degree of Heart Block, Heart Failure Neurological: Any Seizure Disorder Psychiatric illnesses affecting pain perception e.g. severe depression and anxiety disorder Alcohol or substance abuse Chronic Pain, other than chronic knee pain Daily use of strong opioids (morphine, fentanyl, hydromorphone, ketobemidone, methadone, dicomorphine, oxycodone, or meperidine) before operation Impaired Renal Function (defined as preoperative eGFR < 30ml /min /1.73 m2) Impaired Hepatic Function Pregnancy Inability to use PCA Patient refusal to ISB Patient refusal to study Patients do not understand Cantonese or Mandarin