Cable Saddle for Cerclage Fixation Preventing Bone Subsidence
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Solution Overview
Problem
Cerclage cables tend to subside into osteoporotic bone, leading to loosening of the construct and the need for repeated replacement procedures, which is inconvenient for patients and costly.
Innovation Solution
A cerclage system comprising a cable saddle or cable belt with a body having loops and reliefs that conform to the bone contour, and cable links with coupling members that form a passageway to secure the cable, preventing subsidence by distributing the compressive force over a larger surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cerclage cable is used to wrap around bone for fixation, then the bone fracture can be stabilized, but the cable tends to subside into osteoporotic bone causing loosening of the construct
Solution Approach 1:
A cable saddle or cable belt is introduced as an intermediary device between the cerclage cable and the bone. This mediator distributes the compressive force of the cable over a larger surface area of the bone, preventing the cable from directly pressing into and subsiding into the osteoporotic bone, thereby maintaining fixation strength while improving cable stability.
Solution Approach 2:
The cable saddle/belt changes the physical parameters of force distribution by increasing the contact surface area between the cable system and the bone. This parameter change transforms the concentrated point pressure into distributed line or area pressure, preventing subsidence while maintaining the necessary compressive force for fracture stabilization.
2Reliability
If the cable subsides into the bone, then the initial fixation is compromised, but replacing the cable with a new system requires repeated surgical procedures
Solution Approach 1:
The cable saddle or belt is pre-positioned on the bone surface before the cerclage cable is tensioned and secured. This preliminary action ensures that the force-distributing interface is already in place, preventing cable subsidence from occurring in the first place and eliminating the need for future replacement procedures.
Solution Approach 2:
The cable saddle/belt acts as a permanent intermediary structure that remains in place to continuously distribute forces, preventing the recurring subsidence problem that would otherwise require repeated surgical interventions to correct.
3Strength
If a rigid cable system is used for cerclage fixation, then the cable provides strong compression, but it cannot conform to the contour of the bone surface
Solution Approach 1:
The cable saddle or belt is designed with flexible, thin-walled construction that allows it to conform to the complex three-dimensional contour of the bone surface while maintaining its structural integrity and force-distributing capabilities. This flexibility enables adaptation to various bone geometries without sacrificing the compressive strength provided by the cerclage cable.
Solution Approach 2:
The cable saddle/belt structure incorporates dynamic characteristics that allow it to flex and adapt to the bone contour during installation and under physiological loading conditions, while still providing stable force distribution to prevent cable subsidence.
Data Source
AI summary
The present embodiments include a cable cerclage system and method for the correction of fractures. The system and method can include a cable saddle including first and second loops extending from an upper surface thereof, the first and second loops including apertures extending therethrough and sized and shaped to receive a cerclage cable therethrough. The present embodiments are also directed to a cable cerclage system including at least one cable link, the cable link having a through-hole extending therethrough from a first end to a second end and including a first coupling member at a first and a second coupling member at a second end. The first coupling member of a first cable link is configured to couple to the second coupling member of an adjacent second cable link so that the through-holes of the first and second cable links align to form an elongated cerclage cable passageway.