Using standard-length compactors to implant short humeral stems in total shoulder arthroplasty: A cadaver study of humeral stem alignment.
Journal
PloS one
ISSN: 1932-6203
Titre abrégé: PLoS One
Pays: United States
ID NLM: 101285081
Informations de publication
Date de publication:
2022
2022
Historique:
received:
25
10
2021
accepted:
21
04
2022
entrez:
5
5
2022
pubmed:
6
5
2022
medline:
10
5
2022
Statut:
epublish
Résumé
Short-stem implants in shoulder arthroplasty were recently developed and reported clinical outcomes are good. However, radiological analysis often reveals humeral stem misalignment in the frontal plane, along with high filling ratios that can lead to proximal bone remodeling under stress shielding. The aim of this cadaveric study was to test whether using compactors for standard-length (> 100 mm) stems to implant short (< 100 mm) stems reduces the risk of stem misalignment without compromising in terms of a higher filling ratio. In a cadaveric study, twenty short stems were implanted using instrumentation for standard-length stems. Alignment and filling ratios were evaluated on anteroposterior radiographs for both the compactors and the stems. The angular deviations (α) from the humeral axis of the compactors and the short stems were measured. Misalignment was defined as |α| > 5°. Metaphyseal and diaphyseal filling ratios were calculated and defined as either high (≥ 0.7) or low (< 0.7). The median angular deviations of the compactors and the short stems were respectively 1.6° (range, 0.03 to 5.9°) and 1.3° (range, 0.3 to 9.6°). Nineteen of the 20 compactors (95%) and 17/20 short stems (85%) were correctly aligned. The proportions of correctly aligned compactors and stems were not significantly different (95% CI, -0.33 to 0.11; Z-test of proportions p = .60), and the respective angular deviations were significantly correlated (Spearman ρ = .60, p = 0.006). The diaphyseal and metaphyseal filling ratios of the compactors and the stems were all low. In this series of 20 implants in cadavers, the narrow short humeral stems implanted with compactors for standard-length stems were correctly aligned with the humeral axis. This approach may be a way to achieve both correct frontal alignment and low filling ratios.
Sections du résumé
BACKGROUND
Short-stem implants in shoulder arthroplasty were recently developed and reported clinical outcomes are good. However, radiological analysis often reveals humeral stem misalignment in the frontal plane, along with high filling ratios that can lead to proximal bone remodeling under stress shielding. The aim of this cadaveric study was to test whether using compactors for standard-length (> 100 mm) stems to implant short (< 100 mm) stems reduces the risk of stem misalignment without compromising in terms of a higher filling ratio.
METHODS
In a cadaveric study, twenty short stems were implanted using instrumentation for standard-length stems. Alignment and filling ratios were evaluated on anteroposterior radiographs for both the compactors and the stems. The angular deviations (α) from the humeral axis of the compactors and the short stems were measured. Misalignment was defined as |α| > 5°. Metaphyseal and diaphyseal filling ratios were calculated and defined as either high (≥ 0.7) or low (< 0.7).
RESULTS
The median angular deviations of the compactors and the short stems were respectively 1.6° (range, 0.03 to 5.9°) and 1.3° (range, 0.3 to 9.6°). Nineteen of the 20 compactors (95%) and 17/20 short stems (85%) were correctly aligned. The proportions of correctly aligned compactors and stems were not significantly different (95% CI, -0.33 to 0.11; Z-test of proportions p = .60), and the respective angular deviations were significantly correlated (Spearman ρ = .60, p = 0.006). The diaphyseal and metaphyseal filling ratios of the compactors and the stems were all low.
CONCLUSIONS
In this series of 20 implants in cadavers, the narrow short humeral stems implanted with compactors for standard-length stems were correctly aligned with the humeral axis. This approach may be a way to achieve both correct frontal alignment and low filling ratios.
Identifiants
pubmed: 35511898
doi: 10.1371/journal.pone.0268075
pii: PONE-D-21-32611
pmc: PMC9070928
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
e0268075Déclaration de conflit d'intérêts
The authors have declared that no competing interests exist.
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