Continuous bone loss around a tapered uncemented femoral stem: A long-term evaluation with DEXA

Abstract

Background Periprosthetic bone loss is a well-documented phenomenon after uncemented total hip arthroplasty (THA); however, little is known about how bone mineral density (BMD) changes after 2 years.Patients and methods 14 patients with hip arthrosis (group A) were operated with a proximally porous-and hydroxyapatite-coated stem and followed for 10 years with DEXA, radiographs and Harris hip score (HHS). Another group of 14 patients (group B) was evaluated at 6 and 14 years using the same prosthesis and protocol.Results No stem was revised and all stems were wellfixed. At final follow-up, HHS was 97 points in group A after 10 years and 94 points in group B after 14 years. Bone mineral changes in group A were greatest in Gruen zones 1 and 7, where the losses were 31% and 26%, respectively, after 2 years on the operated side. The decrease in BMD continued after 2 years and in Gruen zone 7 it was faster than the rate of bone loss on the control side. In group B, the annual change in BMD on the operated side was not significantly different from the bone loss in group A.Interpretation Up to 14 years after implantation of a tapered uncemented stem, the BMD in the calcar region continues to decrease faster than would be expected from normal ageing.

Changes in periprosthetic bone remodelling after redesigning an anatomic cementless stem

“…Second-generation cementless stems (anatomic design, metaphyseal press-fit, proximal coating) made of titanium still had a decrease of BMD at the end of the second year that ranged from 20% to 25% [9,17]. Tapered femoral components had a proximal loss between 10% to 30% [1,6,19]. Custommade implants reported the best results regarding the proximal loss of BMD, but with a fall of between 10% to 15% at the end of the third year [12,13].…”

“…In the last 20 years, dual-energy X-ray absorptiometry (DEXA) has been used to quantify the changes of bone mineral density (BMD) attributed to periprosthetic remodelling, and it is thought to be ideal for long-term follow-up studies [1,11,21].…”

Modes of periacetabular load transfer to cortical and cancellous bone after cemented versus uncemented total hip arthroplasty: A prospective study using computed tomography‐assisted osteodensitometry

“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Most of these studies have focussed on stress shielding mechanisms after femoral stem implantation. [2][3][4][5][6]10 The most common technique to study bone density (BD) changes is dual X-ray absorptiometry (DXA), which is a reproducible two-dimensional measurement technique. [2][3][4][5][6][7]11,[15][16][17] To allow a differentiated three-dimensional analysis of cortical and cancellous bone structures after THA in vivo we have introduced a novel method of CT-assisted osteodensitometry.…”

“…[2][3][4][5][6]10 The most common technique to study bone density (BD) changes is dual X-ray absorptiometry (DXA), which is a reproducible two-dimensional measurement technique. [2][3][4][5][6][7]11,[15][16][17] To allow a differentiated three-dimensional analysis of cortical and cancellous bone structures after THA in vivo we have introduced a novel method of CT-assisted osteodensitometry. 9,10,13,14 In a previous study we have provided clear evidences for the reproducibility and validity of our method.…”

“…1 In the last century increasing knowledge of load transfer mechanisms and stress distribution patterns after total hip replacements was provided. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Most of these studies have focussed on stress shielding mechanisms after femoral stem implantation. [2][3][4][5][6]10 The most common technique to study bone density (BD) changes is dual X-ray absorptiometry (DXA), which is a reproducible two-dimensional measurement technique.…”