Evidence map›Paper›PMID 42555264›Full record

Trial reportActa orthopaedica2026

Preservation of periprosthetic bone with a collum-fixated short stem versus conventional metaphyseal-fixated stems in total hip arthroplasty: a randomized controlled trial with 2-year follow-up in 61 patients.

Anders Tjønneland, Janus D Christiansen, Thomas Jakobsen, Poul T Nielsen

Abstract readRandomized Controlled TrialComparative Study
In one paragraph

Trial report in Acta orthopaedica, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Anders TjønnelandInterdisciplinary Orthopaedics, Department of Orthopaedic surgery, Aalborg University Hospital, Aalborg, Denmark. anders.tjonneland@gmail.com.ORCID 0009-0001-3416-2054
Janus D ChristiansenInterdisciplinary Orthopaedics, Department of Orthopaedic surgery, Aalborg University Hospital, Aalborg, Denmark.ORCID 0000-0002-0337-3078
Thomas JakobsenInterdisciplinary Orthopaedics, Department of Orthopaedic surgery, Aalborg University Hospital, Aalborg, Denmark.
Poul T NielsenInterdisciplinary Orthopaedics, Department of Orthopaedic surgery, Aalborg University Hospital, Aalborg, Denmark.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

background and purposeWe aimed to compare the effect of 2 femoral stem designs on periprosthetic bone mineral density (BMD) after total hip arthroplasty in a randomized controlled trial. We hypothesized that a short collum-fixated stem (Primoris) would better preserve proximal BMD than a conventional metaphyseal-fixated and diaphyseal engaging stem (Echo).

methods61 patients with primary osteoarthritis were randomized to receive either the Primoris (n = 31) or Echo (n = 30) uncemented femoral stem. DXA scans were performed preoperatively, at 6 weeks, 12 months, and 24 months. The prespecified primary outcome was periprosthetic BMD at 24 months and patient-reported outcomes (EQ-5D, Oxford Hip Score, FJS-12) were collected preoperatively, and at each follow-up were secondary.

resultsAt 24 months, model-based estimates showed significantly higher BMD in the Primoris group than in the Echo group in Gruen zones 3 (mean difference 0.40 g/cm², 95% confidence interval [CI] 0.26-0.53; P < 0.001), 5 (0.20 g/cm², CI 0.07-0.33; P = 0.003), and 7 (0.27 g/cm², CI 0.14-0.41; P < 0.001). These differences corresponded to relative differences of +19.1%, +9.1%, and +14.3%, respectively, compared with the Echo group. In addition, the increase in BMD from 6 weeks to 24 months was significantly greater in the Primoris group in Gruen zone 7 (mean difference in change 0.18 g/cm², CI 0.04-0.32; P = 0.01). PROMs improved similarly in both groups, with no statistically significant between-group differences.

conclusionAt 2 years, the collum-fixated Primoris stem preserved more proximal femoral bone than the Echo stem, while PROMs were comparable between groups. The observed preservation of proximal bone stock may be advantageous for long-term bone maintenance and future revision surgery.

Indexed as

Arthroplasty, Replacement, HipHip ProsthesisOsteoarthritis, HipProsthesis DesignAbsorptiometry, PhotonAgedBone DensityFemaleFemurFollow-Up StudiesHumansMaleMiddle AgedTreatment Outcome

Identifiers

PMID42555264
PMCPMC13444838

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.