The Influence of Implant Design on Periprosthetic Bone Remodelling of two Types of uncemented HA-Coated Hip Stems. A Two-Year Follow-up Study Using Dexa

Abstract

Proximal bone resorption and an increased fracture rate in the ABG-I stem has been shown. For these reasons the ABG-I stem design was changed to the ABG-II. In this study periprosthetic bone loss around the ABG-I vs ABG-II is compared to verify if the design changes resulted in improved proximal bone preservation. Methods 51 patients were randomised to either the ABG-I or ABG-II hip prosthesis. Periprosthetic BMD change at various time points was measured using DEXA. Between the two groups (age, gender, weight etc.) no statistical difference was encountered. Compared to the baseline at two years the ABG-II preserved bone better proximally (e.g. zone 7: ABG-II: −3.7%, ABG-I: −11.9%, p=0.05) than the ABG-I. Distally, the trend was opposite and less bone loss was measured for the ABG-I than the ABG-II in zones 3, 4 and 5 (n.s.). Conclusion this study confirms the philosophy behind the design changes from the ABG-I to ABG-II stem where increased elasticity, more proximal HA-coating, a shorter and distally polished stem, were meant to reduce proximal bone resorption. In future this may lead to fewer periprosthetic fractures and to less complicated revision surgery.

Cross-linked Compared with Historical Polyethylene in THA: An 8-year Clinical Study

“…This can be expected because the acetabular bone-implant interface is closer to the origin of wear debris and because the interface between the proximal femur and hydroxyapatite-coated stem probably is better sealed against particle migration [40]. It also may be a hint that the osteolysis observed is wear particle driven and not bone resorption owing to other effects such as stress shielding.…”

Preoperative bone quality as a factor in dual-energy X-ray absorptiometry analysis comparing bone remodelling between two implant types

“…Hip arthroplasty patients (n=24) having received the Stryker ABG-II total hip were compared to two different patient groups having received the ABG-I total hip system: 1. Twenty-five patients from a previously published prospectively randomised comparison [18] 2. A group of 24 patients selected from the previously published randomised comparison [18] and from Stryker ABG-II (right) implant made of a low modulus titanium alloy and having a shorter small-diameter polished stem, increased proximal HA coating and neck lateralization (130°vs.…”

“…Twenty-five patients from a previously published prospectively randomised comparison [18] 2. A group of 24 patients selected from the previously published randomised comparison [18] and from Stryker ABG-II (right) implant made of a low modulus titanium alloy and having a shorter small-diameter polished stem, increased proximal HA coating and neck lateralization (130°vs. 135°) another study [12] to perfectly match the ABG-II group for gender, age and preoperative bone quality.…”

“…In a prospective randomised trial, it was shown that the design changes from the ABG-I to ABG-II stem result in a trend towards better proximal bone preservation [18]. However, differences in bone mineral density failed to become statistically significant.…”

The Effect of Weekly Risedronate on Periprosthetic Bone Resorption Following Total Hip Arthroplasty

“…Attempts to reduce stress shielding-mediated adaptive bone resorption can be achieved pharma-cologically with bone metabolism-interacting agents such as bisphosphonates (commented in study III) (29)(30)(31)(32), with prosthesis design (commented in study IV) (33)(34)(35) and with component surface coatings (commented in study V) (36)(37)(38)(39).…”