Periprosthetic proximal bone loss after uncemented hip arthroplasty is related to stem size: DXA measurements in 138 patients followed for 2–7 years

Sköldenberg, Olof; Bodén, Henrik; Salemyr, Mats; Ahl, Torbjörn; Adolphson, Per

doi:10.1080/17453670610046307

Cited by 93 publications

(68 citation statements)

References 44 publications

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“…Before the study, we conducted a power analysis based on data obtained from an earlier study of THA performed using the conventional stem (Sköldenberg et al 2006). In a previous study of hip fracture prevention, a 4.8% increase in BMD in the greater trochanter and a 3.4% increase in BMD in the femoral neck (roughly equivalent to Gruen zones 1 and 7) was associated with a 30% reduction in hip fracture risk (McClung et al 2001).…”

Section: Methodsmentioning

confidence: 99%

“…We therefore assumed that a difference in BMD between our groups of 15% in the proximal zones (roughly 3 times as large as the increase in that study) would also be clinically relevant for our group of osteoarthritis patients, to reduce the incidence of late periprosthetic femoral fractures. A power analysis showed that detection of a 15% difference in BMD at the 5% significance level with a standard deviation of 14% (Sköldenberg et al 2006) would require 17 patients in each group. We did not predefine the use of Bonferroni correction for the primary endpoint.…”

Section: Methodsmentioning

confidence: 99%

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Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

Salemyr¹,

Muren²,

Ahl³

et al. 2015

Acta Orthopaedica

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Background and purpose — We hypothesized that an ultra-short stem would load the proximal femur in a more physiological way and could therefore reduce the adaptive periprosthetic bone loss known as stress shielding.Patients and methods — 51 patients with primary hip osteoarthritis were randomized to total hip arthroplasty (THA) with either an ultra-short stem or a conventional tapered stem. The primary endpoint was change in periprosthetic bone mineral density (BMD), measured with dual-energy x-ray absorptiometry (DXA), in Gruen zones 1 and 7, two years after surgery. Secondary endpoints were change in periprosthetic BMD in the entire periprosthetic region, i.e. Gruen zones 1 through 7, stem migration measured with radiostereometric analysis (RSA), and function measured with self-administered functional scores.Results — The periprosthetic decrease in BMD was statistically significantly lower with the ultra-short stem. In Gruen zone 1, the mean difference was 18% (95% CI: −27% to −10%). In zone 7, the difference was 5% (CI: −12% to −3%) and for Gruen zones 1–7 the difference was also 5% (CI: −9% to −2%). During the first 6 weeks postoperatively, the ultra-short stems migrated 0.77 mm more on average than the conventional stems. 3 months after surgery, no further migration was seen. The functional scores improved during the study and were similar in the 2 groups.Interpretation — Up to 2 years after total hip arthroplasty, compared to the conventional tapered stem the ultra-short uncemented anatomical stem induced lower periprosthetic bone loss and had equally excellent stem fixation and clinical outcome.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

Salemyr¹,

Muren²,

Ahl³

et al. 2015

Acta Orthopaedica

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“…This can be ascribed to blood-flow disruption due to femoral canal preparation three to six months after surgery [28]. The major BMD decreases in the greater trochanter (R1) and the calcar (R7) are typical for straight stems [3,21,23,25,27,[29][30][31][32]. They occur mostly due to stress shielding in the very proximal portion of the calcar due to the vast proximal cross section of the implant [28,31].…”

Section: Discussionmentioning

confidence: 99%

The cementless Bicontact® stem in a prospective dual-energy X-ray absorptiometry study

Lerch

Kurtz

Bouguecha

et al. 2012

International Orthopaedics (SICOT)

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Purpose The cementless Bicontact® total hip arthroplasty (THA) system (AESCULAP AG, Tuttlingen, Germany) was introduced in 1986/1987 and has been in successful clinical use in an unaltered form up to today. Although good longterm results with the Bicontact® stem have been published, it is questionable whether the implant provides the criteria for a state-of-the-art stem regarding proximal bone stock preservation. The purpose of the study was to monitor the periprosthetic bone mineral density (BMD) in a prospective two-year follow-up dual-energy X-ray absorptiometry (DEXA) study. Methods After power analysis, a consecutive series of 25 patients with unilateral Bicontact® stem implantation was examined clinically and underwent DEXA examinations. Scans of seven regions of interest were taken preoperatively and at one week, six months, and one and two years. Results One patient required stem revision due to a deep infection. The Harris Hip Score increased significantly by 44 points. The most significant bone loss was observed in the calcar region (R7) in the first six months (−19.2 %). It recovered in the following 18 months to −8.5 %. The BMD in the greater trochanter dropped significantly after six months and remained stable at this level. BMD exceeded baseline values in distal regions and even more in the lesser trochanter region after two years. Conclusions We conclude that the Bicontact® stem provides adequate proximal bone stock preservation. We observed some signs of stress shielding at the tip of the stem, which is inevitable to some degree in THA with cementless straight stems. However, in this prospective DEXA investigation, we showed that proximal off-loading does not occur after THA with the Bicontact® system. Thus, we believe that this stem is still a state-of-the-art implant.

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“…Increase of the stem diameter often necessitated by aging and a thin femoral cortex or reaming of the canal will further promote proximal stress shielding and distal load transfer [42,45]. With smaller stem sizes, the relative stiffness of the stem will become less important, but some studies failed to find any correlation between BMD loss and stem diameter [2,37] or that substantial loss of BMD also occurs with smaller stem sizes [46]. Thus, there might be indications for the use of flexible stems down to size 13, perhaps even smaller, if they can be manufactured without any increased risk of stem breakage.…”

Section: Discussionmentioning

confidence: 99%

“…Use of solid metallic stems fixed without cement has consistently caused proximal bone loss [34,39,40,46]. Increase of the stem diameter often necessitated by aging and a thin femoral cortex or reaming of the canal will further promote proximal stress shielding and distal load transfer [42,45].…”

Section: Discussionmentioning

confidence: 99%

Fixation and Bone Remodeling Around a Low Stiffness Stem in Revision Surgery

Kärrholm¹,

Razaznejad²

2008

Clinical Orthopaedics &Amp; Related Research

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Femoral stems with reduced stiffness have the potential of decreasing stress shielding and could be an alternative in revision surgery when restoration of bone stock is required. We retrospectively reviewed 38 patients (40 stems) with a central core of cobalt-chromium surrounded by a polymer and an outer titanium mesh layer containing a proximal coating of hydroxyapatite/tricalcium phosphate; 30 of the 38 patients (32 hips) had a minimum 2-year followup. We impacted morselized allograft around the stem in 28 of 32 revisions. Repeated radiostereometric examinations showed medial, distal, and posterior migration (median, 0.21 mm, 0.17 mm, and 0.96 mm, respectively) of the femoral head center for up to 6 months followed by stabilization. Measurements of bone mineral density in the seven Gruen zones at 6 months revealed either a decrease (down to a median of 3%), no change, or a slight increase (up to 5%) followed by a further increase up to 2 years in three of the regions (2, 3, and 5). Conventional radiography at 2 years demonstrated graft remodeling and incomplete radiolucent lines in 19 hips, mainly in Regions 1 and 7. Two hips were reoperated on as a result of dislocation, but none of the stems had been revised.

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Periprosthetic proximal bone loss after uncemented hip arthroplasty is related to stem size: DXA measurements in 138 patients followed for 2–7 years

Cited by 93 publications

References 44 publications

Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

The cementless Bicontact® stem in a prospective dual-energy X-ray absorptiometry study

Fixation and Bone Remodeling Around a Low Stiffness Stem in Revision Surgery

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