66 year old female sustained a fracture neck of femur in dubai and was treated by a modular bipolar arthroplasty. She presented with groin pain one year postop.
Bone scan confirmed acetabular uptake suggesting acetabular wear.
Xray showed about 1.5 cm decreased femoral offset.
1. Did this contribute to her aceatbular wear?
2. Was bipolar indicated in a fracyure neck at 66 years( active female)
3. Is metal bipolar succesful in a porotic female
options please
According to Campbell 11th edition:"Primary total hip arthroplasty is indicated in patients with significant preexisting joint destruction caused by rheumatoid disease, osteonecrosis, or osteoarthritis.", Otherwise they recommend modular bipolar/unipolar based on whether they are community or household ambulators..!!
ReplyDeleteOh yes, These are the standard indications. Some one with a physiological age below 70 with a lifespan of > 10 years i beleive THR is a better option inspite of higher dislocation rates as proved by various studies, Marsh in jbjsB etc. Use larger heads and tighter reduction. In this case the smaller offset added to the trouble in this porotic person. Lets look at patients rather than disease centered care. the activity and lifespan of pateints vary inspite of their age.
ReplyDeletefew doubts, sir..
ReplyDelete1) what kind of poly is usually used in this bipolar..and can wear be such a major issue in just one year post op period? how can we be sure its wear thats causing pain in this case? what are other causes that we have to think of? could it be a low grade infection?
2) where is this 1.5 cm difference of offset? from whatever i could measure from the pic (might be wrong) the body lever arm of both sides looks comparable and the abductor lever is marginally less in operated side but then the LT is more prominent in that side (? ext rotated limb). hip centre wont change in a hemireplacement done for #NOF,right?..is there flexion deformity of hip? (obt formaen looks small)
The wear was in the articular cartilage. The offset was about 2 cm less. It could cause excessive wear. They have regular poly for the bipolar poly I do agree the the limb position is Not identical. I think a the was more acceptable in active lady. We increased the offset using an 4 mm offset liner.
ReplyDeleteHi Dr Varghese
ReplyDeleteVery interesting case. I had a very similar case recently, who presented with groin pain and severe Abductor Lurch after a bipolar hemi with a 35.5 exeter stem.
The primary problem with your case (and mine as well) is the relatively large offset in the native hip with a very narrow canal. I tell my trainees to look at the normal side and template if possible to prevent being in this situation.
Majority of implant systems have smaller offset for smaller stems(If you design a small stem with large offset the risk of stem fracture from the bending moment is deemed too high).
I did exactly like what you did with the socket - used a Pinnacle with 4 mm Poly/36 head. I revised the stem with an S-ROM. I used a small(11 mm) stem with a 42 mm offset neck and thus could increase the offset to match the other side.
You are spot on as far as the acetabular wear is concerned. It has to do with the offset. I am sure your patient was lurching as well!
I ask my juniors what would they do if the patient is your mother. If she is my mother I would definitely go for a THR.
The only caveat is I would choose the surgeon very carefully!
By the way Xrays in your blog are fascinating!
Great post. My aunt recently did bipolar replacement and she's very happy now.
ReplyDelete