Alendronate reduces periprosthetic bone loss after uncemented primary total hip arthroplasty - a 5-year follow-up of 16 patients.
OBJECTIVE
Periprosthetic bone loss, especially in the proximal part of the femur, is common after cemented and uncemented total hip arthroplasty (THA). Short-term studies suggest that bisphosponates can minimize this bone loss related to stress-shielding phenomenon. The aim of the present randomized study was to investigate whether the positive effect of a 6 months alendronate treatment postoperatively still exists at five-year follow up.


METHODS
Sixteen uncemented primary THA patients were randomized to receive either 10mg alendronate + 500 mg calcium (n = 7) or 500 mg calcium only (n = 9) daily for 6 months postoperatively. Periprosthetic bone mineral density (BMD) was measured with the dual X-ray absorptiometry (DXA) postoperatively and at 6, 12, 24, 36 and 60 months follow-up.


RESULTS
At the 5-year follow up, the calcium group showed mean BMD decreases of 23.1% (SD 14.6) in the proximal part of the femur (prROI) and 9.6% (SD 14.9) in total femoral regions of interest (totROI). In the alendronate group the corresponding BMD decreases were 13.6% (SD 19.0) and 3.9% (SD 7.6) respectively. The positive effect of alendronate was already demonstrated during the first six months postoperatively. Subsequently the bone loss was equal in both groups, and the 5-year BMD changes were not significantly different between the groups.


CONCLUSIONS
Alendronate seems to decrease early periprosthetic bone loss after arthroplasty but this pilot study could not provide enough evidence that the positive effect noted in the early postoperative period is still maintained 5 years after the operation.
Tapaninen
T S
TS
Deparment of Orthopedics and Traumatology, Kuopio University Hospital, Kuopio, Finland, Bone and Cartilage Research Unit (BRCU), University of Kuopio, Kuopio, Finland. tapanine@hytti.uku.fi
Venesmaa
P K
PK
Jurvelin
J S
JS
Miettinen
H J A
HJ
Kröger
H P J
HP
D000368:Aged; D019386:Alendronate / Q000627:therapeutic use*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015519:Bone Density; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D001862:Bone Resorption / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000150:complications / Q000473:pathology / Q000601:surgery*; D010865:Pilot Projects; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome
D050071:Bone Density Conservation Agents; D019386:Alendronate