title: Preoperative bone quality as a factor in dual-energy X-ray absorptiometry analysis comparing bone remodelling between two implant types.
abstract: Recently it was shown that the design changes from the ABG-I to ABG-II hip stem resulted in a better, although not significant, proximal bone preservation. Our hypothesis was that by matching patients for preoperative bone quality, statistical power would increase and that the trend of better proximal bone preservation in ABG-II might become significant. Twenty-four ABG-II patients were compared to two different ABG-I groups: (1) 25 patients from our earlier prospective study and (2) a group of 24 patients selected to perfectly match the ABG-II group regarding gender, age and preoperative bone quality. Postoperative changes in periprosthetic bone mineral density (BMD) were quantified at 2 years postoperatively using DEXA scanning. Bone preservation (less BMD loss) was better for the ABG-II than the ABG-I (all two groups) in the proximal zones 1 and 7. In Gruen zone 7, a statistically significant difference was found for group B (p = 0.03). By matching patients for preoperative bone quality and gender, a statistical significant difference was found in proximal bone preservation in favour of ABG-II. In future comparative bone remodelling studies using DEXA, patients should be matched for preoperative bone quality and gender.
authors.affiliation: Department of Orthopaedic Surgery, Atrium Medical Center, Heerlen, The Netherlands. bchvanderwal@yahoo.com
authors.forename: Bart Cornelis Hendrikus
authors.initials: BC
authors.lastname: van der Wal
authors.forename: Ali
authors.initials: A
authors.lastname: Rahmy
authors.forename: Bernd
authors.initials: B
authors.lastname: Grimm
authors.forename: Ide
authors.initials: I
authors.lastname: Heyligers
authors.forename: Alphons
authors.initials: A
authors.lastname: Tonino
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology*; D016723:Bone Remodeling; D005260:Female; D005269:Femur / Q000503:physiopathology*; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D012737:Sex Factors