In the posterior approach, the patient lays on their side and especially if the patient has had prior shoulder pain on the other side this pain can be aggravated.  This is because of positioning. Intraoperatively we provide adequate cushioning, we place axillary support to prevent compression of the nerves in the axilla, but occasionally a patient may wake up with pain in the other shoulder after a hip replacement.  If the left hip is done, then the patient may wake up with pain in the right shoulder.  This pain, which is positional, is expected to go away unless there was an underlying issue with the shoulder before the surgery which will need to be addressed separately.