Hi, thanks for writing to HCM.
By the description of symptoms, I feel that the culprit is not your total hip replacement
(THR). As you are alright without any symptoms and trouble upto 5 months after THR, I rule out this as your cause of symptoms.
Generally, If there is any problem in the primary surgery (THR), symptoms tend to be present since the day of surgery without any pain free interval.
I suspect that the cause of your symptoms could be a disc disease
of lumbar spine
So i suggest you to have an MRI
scan of Lumbar spine to rule out the spinal causes. Hope this helps