TY - JOUR

T1 - Bone remodelling around the Metha short stem in total hip arthroplasty

T2 - A prospective dual-energy X-ray absorptiometry study

AU - Lerch, Matthias

AU - Von Der Haar-Tran, Annelene

AU - Windhagen, Henning

AU - Behrens, Bernd A.

AU - Wefstaedt, Patrick

AU - Stukenborg-Colsman, Christina M.

N1 - Funding information: The study was performed in subproject D6 of the collaborative research center 599 “Sustainable degradable and permanent implants out of metallic and ceramic materials”. The authors thank the German Research foundation (DFG) for financial support.

PY - 2012/3

Y1 - 2012/3

N2 - Purpose: On the basis of positive clinical results with mid- and long-term follow-up using the Mayo short stem, the Metha neck-preserving stem (BBraun, Aesculap, Tuttlingen, Germany) was introduced. The purpose of this study was to validate the implant design by direct acquisition of bone remodelling data from total hip arthroplasty (THA) recipients using dual-energy X-ray absorptiometry (DEXA). Methods: After power analysis, 25 patients were included in this prospective study. Patients were examined clinically and underwent DEXA examinations preoperatively and postoperatively at one week, six months and one and two years after THA. Gruen zones were adapted to the short stem design (R1-R7). Results: The Harris Hip Score (HHS) increased significantly by 31 points. No stem had to be revised. Bone mineral density (BMD) in the greater trochanter decreased significantly from 0.78 g/cm 2 postoperatively to 0.72 g/cm 2 two years after surgery. Marginal changes were seen in the lateral distal regions (R4-R5). In the minor trochanter region, BMD increased significantly after two years by 12.9%. In the calcar region, BMD exceeded the baseline value by 6.1% two years after implantation. Conclusions: Stress shielding seems to occur at the greater trochanter due to the vast cross-section of the implant. However, the aim of proximal load transfer of the Metha stem seems to be partially achieved. DEXA analysis revealed a concentrated load distribution on the medial portion of the femur, which is an important region to guarantee long-term implant survival.

AB - Purpose: On the basis of positive clinical results with mid- and long-term follow-up using the Mayo short stem, the Metha neck-preserving stem (BBraun, Aesculap, Tuttlingen, Germany) was introduced. The purpose of this study was to validate the implant design by direct acquisition of bone remodelling data from total hip arthroplasty (THA) recipients using dual-energy X-ray absorptiometry (DEXA). Methods: After power analysis, 25 patients were included in this prospective study. Patients were examined clinically and underwent DEXA examinations preoperatively and postoperatively at one week, six months and one and two years after THA. Gruen zones were adapted to the short stem design (R1-R7). Results: The Harris Hip Score (HHS) increased significantly by 31 points. No stem had to be revised. Bone mineral density (BMD) in the greater trochanter decreased significantly from 0.78 g/cm 2 postoperatively to 0.72 g/cm 2 two years after surgery. Marginal changes were seen in the lateral distal regions (R4-R5). In the minor trochanter region, BMD increased significantly after two years by 12.9%. In the calcar region, BMD exceeded the baseline value by 6.1% two years after implantation. Conclusions: Stress shielding seems to occur at the greater trochanter due to the vast cross-section of the implant. However, the aim of proximal load transfer of the Metha stem seems to be partially achieved. DEXA analysis revealed a concentrated load distribution on the medial portion of the femur, which is an important region to guarantee long-term implant survival.

UR - http://www.scopus.com/inward/record.url?scp=84859159994&partnerID=8YFLogxK

U2 - 10.1007/s00264-011-1361-0

DO - 10.1007/s00264-011-1361-0

M3 - Article

C2 - 21935621

AN - SCOPUS:84859159994

VL - 36

SP - 533

EP - 538

JO - International orthopaedics

JF - International orthopaedics

SN - 0341-2695

IS - 3

ER -