The effect of long calcar screws on the primary stability of 3-part, varus impacted proximal humeral fractures compared to short calcar screws: a real fracture simulation study.
3-part
Calcar
Length
Plate
Screw
Simulated humeral fractures
Stability
Journal
Archives of orthopaedic and trauma surgery
ISSN: 1434-3916
Titre abrégé: Arch Orthop Trauma Surg
Pays: Germany
ID NLM: 9011043
Informations de publication
Date de publication:
May 2023
May 2023
Historique:
received:
17
09
2021
accepted:
27
04
2022
medline:
19
4
2023
pubmed:
1
6
2022
entrez:
31
5
2022
Statut:
ppublish
Résumé
Complex proximal humeral fracture ranks among the most common fracture types, especially in elderly patients. In locked plate fixation of proximal humerus fractures, the calcar is deciding for screws providing further medial column support. To date, the biomechanical effect of the length of these calcar screws is not well known. The purpose of this study was to analyze the effect of long calcar screws on fresh frozen prefractured cadaveric specimens. In the present biomechanical study, 8 pairs of cadaveric proximal humeri were fractured identically using a custom-made fracture simulator. ORIF was performed using a locking plate (PHILOS; Fa. Synthes). The specimens were tested in a biomechanical setup under increased axial load without any calcar screws installed, with short calcar screws and long calcar screws installed. Strain gages (4-wire-120 Ohm, Fa. Vishay) mounted on the locking plate were used to evaluate the fixation strain and to give an estimate for primary stability.. The measured strain of the locking plate without calcar screws (804,64 µm/m) at maximum load (200 N) was significantly higher than with short (619,07 µm/m; p = 0.02) or long calcar screws (527,31 µm/m; p = 0.007). Additionally, strain with short calcar screws was noticeably higher in comparison to long calcar screws (619,07 µm/m vs. 527,31 µm/m; p = 0.03). Use of calcar screws improves the stability of realistically impacted 3-part varus humeral fractures. Long calcar screws that are positioned as close as possible to the joint provide further primary stability compared to short calcar screws. Basic science study.
Sections du résumé
BACKGROUND
BACKGROUND
Complex proximal humeral fracture ranks among the most common fracture types, especially in elderly patients. In locked plate fixation of proximal humerus fractures, the calcar is deciding for screws providing further medial column support. To date, the biomechanical effect of the length of these calcar screws is not well known. The purpose of this study was to analyze the effect of long calcar screws on fresh frozen prefractured cadaveric specimens.
METHODS
METHODS
In the present biomechanical study, 8 pairs of cadaveric proximal humeri were fractured identically using a custom-made fracture simulator. ORIF was performed using a locking plate (PHILOS; Fa. Synthes). The specimens were tested in a biomechanical setup under increased axial load without any calcar screws installed, with short calcar screws and long calcar screws installed. Strain gages (4-wire-120 Ohm, Fa. Vishay) mounted on the locking plate were used to evaluate the fixation strain and to give an estimate for primary stability..
RESULTS
RESULTS
The measured strain of the locking plate without calcar screws (804,64 µm/m) at maximum load (200 N) was significantly higher than with short (619,07 µm/m; p = 0.02) or long calcar screws (527,31 µm/m; p = 0.007). Additionally, strain with short calcar screws was noticeably higher in comparison to long calcar screws (619,07 µm/m vs. 527,31 µm/m; p = 0.03).
CONCLUSION
CONCLUSIONS
Use of calcar screws improves the stability of realistically impacted 3-part varus humeral fractures. Long calcar screws that are positioned as close as possible to the joint provide further primary stability compared to short calcar screws.
LEVEL OF EVIDENCE
METHODS
Basic science study.
Identifiants
pubmed: 35635575
doi: 10.1007/s00402-022-04473-7
pii: 10.1007/s00402-022-04473-7
pmc: PMC10110638
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
2485-2491Informations de copyright
© 2022. The Author(s).
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