Mechanical Wear Analysis Helps Understand a Mechanism of Failure in Retrieved Magnetically Controlled Growing Rods: A Retrieval Study
Purpose: To assess the relationship between mechanical wear and the failure of the internal lengthening mechanism in retrieved MAGnetic Expansion Control (MAGEC) growing rods.
Methods: This study included 34 MAGEC rods retrieved from 20 patients. The state of the internal mechanism and mechanical wear were assessed in all the rods using plain radiographs and visual inspection. Metrology was then performed to assess the topography and mechanical wear of the telescopic bars, using a Talyrond 365 (Taylor Hobson, Leicester, UK) roundness measuring machine.
Results: Plain radiographs showed evidence of a broken internal mechanism in 29% of retrieved rods. Single-side wear marks were found in 97% of retrieved rods. Material loss was found to significantly increase in rods with a damaged internal mechanism (p<0.05) and rods with longer time in situ (r=0.692, p<0.05).
Conclusion: We found an association between damage to the internal mechanism of the rods and (1) patterns of single-side longitudinal wear marks and (2) increased material loss. As the material loss was also found to increase over time of rod in situ, we emphasise the importance of early detection and revision of failed MAGEC rods in clinical practice.
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On 05 Aug, 2020
On 24 Jul, 2020
On 22 Jul, 2020
On 21 Jul, 2020
On 21 Jul, 2020
On 13 Jul, 2020
On 08 Jul, 2020
On 07 Jul, 2020
On 07 Jul, 2020
On 23 Jun, 2020
On 22 Jun, 2020
On 21 Jun, 2020
On 21 Jun, 2020
Posted 05 May, 2020
Received 02 Jun, 2020
On 02 Jun, 2020
Received 24 May, 2020
On 11 May, 2020
Invitations sent on 04 May, 2020
On 04 May, 2020
On 22 Apr, 2020
On 21 Apr, 2020
On 21 Apr, 2020
On 20 Apr, 2020
Mechanical Wear Analysis Helps Understand a Mechanism of Failure in Retrieved Magnetically Controlled Growing Rods: A Retrieval Study
On 05 Aug, 2020
On 24 Jul, 2020
On 22 Jul, 2020
On 21 Jul, 2020
On 21 Jul, 2020
On 13 Jul, 2020
On 08 Jul, 2020
On 07 Jul, 2020
On 07 Jul, 2020
On 23 Jun, 2020
On 22 Jun, 2020
On 21 Jun, 2020
On 21 Jun, 2020
Posted 05 May, 2020
Received 02 Jun, 2020
On 02 Jun, 2020
Received 24 May, 2020
On 11 May, 2020
Invitations sent on 04 May, 2020
On 04 May, 2020
On 22 Apr, 2020
On 21 Apr, 2020
On 21 Apr, 2020
On 20 Apr, 2020
Purpose: To assess the relationship between mechanical wear and the failure of the internal lengthening mechanism in retrieved MAGnetic Expansion Control (MAGEC) growing rods.
Methods: This study included 34 MAGEC rods retrieved from 20 patients. The state of the internal mechanism and mechanical wear were assessed in all the rods using plain radiographs and visual inspection. Metrology was then performed to assess the topography and mechanical wear of the telescopic bars, using a Talyrond 365 (Taylor Hobson, Leicester, UK) roundness measuring machine.
Results: Plain radiographs showed evidence of a broken internal mechanism in 29% of retrieved rods. Single-side wear marks were found in 97% of retrieved rods. Material loss was found to significantly increase in rods with a damaged internal mechanism (p<0.05) and rods with longer time in situ (r=0.692, p<0.05).
Conclusion: We found an association between damage to the internal mechanism of the rods and (1) patterns of single-side longitudinal wear marks and (2) increased material loss. As the material loss was also found to increase over time of rod in situ, we emphasise the importance of early detection and revision of failed MAGEC rods in clinical practice.
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Figure 11