Continuous bone loss around a tapered uncemented femoral stem: a long-term evaluation with DEXA.
BACKGROUND
Periprosthetic bone loss is a well-documented phenomenon after uncemented total hip arthroplasty (THA); however, little is known about how bone mineral density (BMD) changes after 2 years.


METHODS
14 patients with hip arthrosis (group A) were operated with a proximally porous- and hydroxyapatite-coated stem and followed for 10 years with DEXA, radiographs and Harris hip score (HHS). Another group of 14 patients (group B) was evaluated at 6 and 14 years using the same prosthesis and protocol.


RESULTS
No stem was revised and all stems were well-Fixed. At final follow-up, HHS was 97 points in group A after 10 years and 94 points in group B after 14 years. Bone mineral changes in group A were greatest in Gruen zones 1 and 7, where the losses were 31% and 26%, respectively, after 2 years on the operated side. The decrease in BMD continued after 2 years and in Gruen zone 7 it was faster than the rate of bone loss on the control side. In group B, the annual change in BMD on the operated side was not significantly different from the bone loss in group A.


CONCLUSIONS
Up to 14 years after implantation of a tapered uncemented stem, the BMD in the calcar region continues to decrease faster than would be expected from normal ageing.
Bodén
Henrik S G
HS
Division of Orthopaedics, Karolinska Institutet at Danderyd Hospital, Stockholm, Sweden. henrik.boden@ds.se
Sköldenberg
Olof G
OG
Salemyr
Mats O F
MO
Lundberg
Hans-Jerker
HJ
Adolphson
Per Y
PY
D015502:Absorptiometry, Photon; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015519:Bone Density; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery; D011474:Prosthesis Design; D013997:Time Factors