Periprosthetic bone loss after insertion of an uncemented, customized femoral stem and an uncemented anatomical stem

Abstract

Background and purposeCustomized femoral stems are designed to have a perfect fit and fill in the femur in order to achieve physiological load transfer and minimize stress shielding. Dual-energy X-ray absorptiometry (DXA) is regarded as an accurate method for detection of small alterations in bone mineral density (BMD) around hip prostheses. We present medium-term DXA results from a randomized study comparing a customized and an anatomical femoral stem.Methods100 hips were randomized to receive either the anatomical ABG-I stem or the Unique customized femoral stem, both uncemented. DXA measurements were conducted postoperatively and after 3, 6, 12, 24, 36, and 60 months, and BMD was computed for each of the 7 Gruen zones in the proximal femur.ResultsResults from 87 patients were available for analysis. 78 completed the 5-year follow-up: 35 patients in the ABG group and 43 patients in the Unique group. In both groups, we found the greatest degree of bone loss in the proximal Gruen zones. In zone 1, there was 15% reduction in BMD in the ABG-I group and 14% reduction in the Unique group. In zone 7, the reduction was 28% in the ABG-I group and 27% in the Unique group. The only statistically significant difference between the groups was found in Gruen zone 4, which is distal to the tip of the stem, with 1.6% reduction in BMD in the ABG-I group and 9.7% reduction in the Unique group (p = 0.003).Interpretation5-year DXA results showed that because of stress-shielding, proximal bone loss could not be avoided—either for the anatomical ABG-I stem or for the customized Unique stem.

Larger femoral periprosthetic bone mineral density decrease following total hip arthroplasty for femoral neck fracture than for osteoarthritis: A prospective, observational cohort study

“…Similar to prior studies, the cohort in this study experienced large decreases in BMD in zones 1 and 7,31,32 while the remaining zones exhibited smaller BMD changes. In contrast, the patients with a later periprosthetic fracture experienced large losses more distally (i.e., in zones 2 and 6, but with relatively modest changes in the remaining zones) (Table ).…”

Periprosthetic bone density changes after MiniHipTMcementless femoral short stem: one-year results of dual-energy X-ray absorptiometry study

“…Zimmer), ABG 1 or 2 (Fa. Stryker)] a significantly higher bone loss especially in Gruen zone 7 than the MiniHip TM [19, 22, 30]. One explanation for the behavior of the standard shaft prostheses is that the stress shielding increases by the increase in stem length and thus the proximal force transmission is reduced [31, 32].…”

Raloxifene Prevents Early Periprosthetic Bone Loss for Postmenopausal Women after Uncemented Total Hip Arthroplasty: A Randomized Placebo‐Controlled Clinical Trial

“…Recent studies have indicated that female patients with low systemic bone mineral density (BMD) show greater bone loss in parts of the zone around the prosthesis after cementless THA than patients with normal BMD 6,7 . Low BMD contributes to advanced implant migration in the early stage after THA, with worse initial stability and delayed osseointegration 8,9 .…”