Standard of care for uncemented knee and hip prosthesis rehab

[truthseeker]

Hi all,

I have been seeing more and more uncemented TKA and THA procedures done and I am wondering what is the standard of practice with regard to weight-bearing status.

Do you start them partial WB or WBAT? If partial, what is the rationale and for how long? ( I realize that it depends somewhat upon the patient's bone density but in general . . .)

Any guidance would be appreciated.

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[Jeff Smoker]

Unless you have some really good reason (ie periprosthetic fracture) they are all usually WBAT.

I don't know if your confusion stems from cemented vs uncemented and if there's a difference in rehab protocol. Rehab is usually the same.

As far as cemented vs uncemented, current standard of care for primary THA is uncemented. Across the board, most primaryTKA are cemented (I believe the number is over 90%), but there are proponents of uncemented TKA out there.

 

[truthseeker]

Unless you have some really good reason (ie periprosthetic fracture) they are all usually WBAT.

I don't know if your confusion stems from cemented vs uncemented and if there's a difference in rehab protocol. Rehab is usually the same.

As far as cemented vs uncemented, current standard of care for primary THA is uncemented. Across the board, most primaryTKA are cemented (I believe the number is over 90%), but there are proponents of uncemented TKA out there.

Jeff,

The reason I asked is that one of our orthopedic surgeons has people arbitrarily 25% WB for what seems to be a variable length of time for both uncemented knees and hips. It just seems to be very very conservative. From a rehab standpoint, the sooner we can get them walking normally the better the maintenance of knee extension in TKAs.

I have been telling my patients that if the surgeon was adamant about weight bearing limitations, he would have said 0%. Sounds like you are confirming my suspicions.

Thanks

 

[skiz knot]

Jeff,

The reason I asked is that one of our orthopedic surgeons has people arbitrarily 25% WB for what seems to be a variable length of time for both uncemented knees and hips. It just seems to be very very conservative. From a rehab standpoint, the sooner we can get them walking normally the better the maintenance of knee extension in TKAs.

I have been telling my patients that if the surgeon was adamant about weight bearing limitations, he would have said 0%. Sounds like you are confirming my suspicions.

Thanks

Some people are of the mindset (probably correctly) that for maximal bony ingrowth to occur, weight bearing should be restricted. Studies have shown that implant micromotion >150 um is associated with fibrous ingrowth (bad). Dog studies have shown <28 um micromotion is necessary to prevent inhibition of bony ingrowth.
As far as I know, there are no studies saying non-cemented implants do better or worse with immediate full weight bearing, however YOU, should NOT be advising your patients on weight bearing restrictions unless you have consulted with the physician that placed them.

 

[truthseeker]

Some people are of the mindset (probably correctly) that for maximal bony ingrowth to occur, weight bearing should be restricted. Studies have shown that implant micromotion >150 um is associated with fibrous ingrowth (bad). Dog studies have shown <28 um micromotion is necessary to prevent inhibition of bony ingrowth.
As far as I know, there are no studies saying non-cemented implants do better or worse with immediate full weight bearing, however YOU, should NOT be advising your patients on weight bearing restrictions unless you have consulted with the physician that placed them.

I don't discourage them from following the restrictions, I just seem to see a variety of guidelines varying from surgeon to surgeon from different practice groups. So I tell them that if they have to choose between falling down and putting more than 25% weight on their leg, to put their foot down and not fall.
Thanks for the detail though.