[Dose-dependent prevention of early periprosthetic bone loss by alendronate].
OBJECTIVE
Periprosthetic bone loss occurs in the first six months after total hip arthroplasty (THA) and is felt to be largely the result of initial operative irritation, immobilization, and stress shielding. This study (a prospective, randomized, open, blinded endpoint evaluation) aims at preventing bone loss around the stem with an oral bisphosphonate.


METHODS
66 healthy subjects with uncemented THA and low lumbar bone mass density (BMD) (negative T score) were treated post-operatively with alendronate as follows: n = 21 with 10 mg/d for 10 weeks (A), n = 21 20 mg/d for 5 weeks (B), n = 24 no treatment for controls (C). The periprosthetic BMD in the Gruen zones (ROI) was measured after the 2nd, 4th, 6th, and 12th month by DEXA as a percentage of the value measured one week after surgery.


RESULTS
In C, there was significant bone loss in all ROI during the first months and a deficit of 29 % in ROI 7 following one year. In B, bone loss was completely prevented up to the second month, in ROI 7, a significant difference in comparison to C was registered for the entire year. In A, significant bone loss reduction during 12 months was seen.


CONCLUSIONS
Alendronate, therefore, is capable of preventing initial periprosthetic bone loss. A dosage of 20 mg/d is required initially with daily treatment lasting at least 10 weeks.
Hennigs
T
T
Orthopädische Universitätsklinik Stiftung Friedrichsheim, Frankfurt, Germany.
Arabmotlagh
M
M
Schwarz
A
A
Zichner
L
L
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019386:Alendronate / Q000008:administration & dosage* / Q000009:adverse effects; D019644:Arthroplasty, Replacement, Hip; D015519:Bone Density / Q000187:drug effects; D001851:Bone Diseases, Metabolic / Q000175:diagnosis / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis / Q000517:prevention & control*; D011446:Prospective Studies; D016896:Treatment Outcome
D019386:Alendronate