Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency care for chest pain, sudden shortness of breath, fainting, or coughing up blood, as these can be signs of a blood clot in the lungs.
Contact the surgical team promptly for increasing wound redness, drainage, fever, or worsening pain.
Sudden calf swelling or pain also needs urgent medical assessment.
Regular follow-up helps the healthcare team assess pain, movement, and changes on imaging.
The schedule depends on the affected joint, disease stage, and treatment plan.
Report increasing pain, new pain at rest, a worsening limp, or reduced joint movement rather than waiting for the next routine visit.
People with risk factors for disease in more than one joint should mention any new bone or joint pain during follow-up.
New symptoms do not necessarily mean that another area is affected, but they may need assessment.
The article also says
Early osteonecrosis may be monitored with repeat examinations and imaging.
After surgery, follow instructions about wound care, activity, physical therapy, and weight-bearing.
Recovery time varies by procedure.
Every sign above is quoted from the sofidex article on Avascular necrosis of bone. If you are not sure, err upward — it is always reasonable to be checked.