I don't really understand that sentence. Do you mean to say that all joints will not flex to more than 90??
I am doing post op checks for patients one year or more after their surgery, and some will flex to 120 plus quite easily. Some don't though.
Some have restricted movement from soft tissue tightness, and sometimes there is impingement at the end of available range. Often that is dependent on the orientation of the implants, or maybe heterotrophic bone.
Some of our surgeons advise their patients that they will never be able to flex "much more than 90".
... which brings me to the questions of "Hip Precautions".
Is everyone advising on the usual hip precautions these days? ... there is evidence that a stable hip is stable, and instability often is a result of inadequate placement of the implants. How long do you tell patients not to flex beyond 90 or adduct past mid-line?
It is really quite limiting for a patient if they are strictly to observe those rules for ever!
Here's another thing: In the UK we'd tell our patients that supine with a pillow between their legs was safest sleep position. If they really could not sleep supine we'd advise them to lie on their OPERATED side, with a pillow between their knees. Obviosuly this would be uncomfortable for most people until the immediate post-op swelling/pain had subsided.
Here in Calgary they are advised to lie on their GOOD side with pillows supporting their operated leg. This, I always thought, is the least safe position as the leg can "fall into flex/add". Indeed I found one of my Home Care patients had subluxed her hip sleeping in this position. I told her to stop doing it!! (and reduce flexion to max of 70 until seen again by the surgeon)
I'd be interested to know other people's experiences/views?