Cable Tensioner for Periprosthetic Fracture Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fractures around implants pose unique fixation challenges due to changes in bone structure and interference from implants, making treatment of periprosthetic fractures complicated by osteoporosis and the presence of implants like stems, rods, and methylmethacrylate, which block intramedullary fixation and screw placement.
Innovation Solution
A system comprising a compression plate with cerclage cables and supplemental plates, featuring integrated cable securing structures and crimp lugs, allows for secure fixation without bicortical screws, enabling tensioning and retention of cables using a single instrument, ensuring stable compression between the plate and bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard plating with bicortical screws is used, then strong fixation is achieved, but the procedure is impossible due to implant blocking the medullary canal
Solution Approach 1:
The fixation system is divided into two independent components: a plate attached to the lateral bone surface and cerclage cables wrapped around the bone. This segmentation allows fixation without requiring medullary canal access, as the cables create circumferential compression while the plate provides lateral stabilization.
Solution Approach 2:
Instead of approaching the bone from the medullary canal side (internal to external), the system approaches from the external cortical surface. The plate is attached externally and the cables are tensioned from the outside, inverting the traditional fixation approach to work around rather than through the blocking implant.
2Ease of operation
If unicortical screws are used, then implant interference is avoided, but fixation strength is reduced
Solution Approach 1:
The system merges two fixation mechanisms: unicortical screws attached to the plate and cerclage cables wrapped around the bone. The screws provide initial plate attachment while the cables provide circumferential compression, combining the advantages of both methods to achieve adequate fixation strength without bicortical penetration.
Solution Approach 2:
The fixation system uses composite construction combining a rigid plate, flexible cables, and tensioning mechanics. This composite approach allows the system to achieve fixation strength equivalent to or greater than bicortical screws alone, while maintaining surgical accessibility and avoiding implant interference.
3Reliability
If separate cable tensioner and tension holder instruments are used, then cable tensioning is possible, but the procedure becomes complex and difficult to operate
Solution Approach 1:
The cable tensioner and tension holder functions are merged into a single integrated instrument. The instrument includes a body with a cable passage, a tensioning mechanism, and a locking feature that maintains tension, eliminating the need for separate instruments and simplifying the surgical procedure while maintaining reliable tension retention.
4Ease of manufacture
If cable tension is applied with existing tools, then cable securing is achieved, but micromotion causes significant tension loss
Solution Approach 1:
The cable tensioning instrument incorporates dynamic adjustment capabilities with a ratchet mechanism or threaded rod that allows progressive tensioning and self-locking. This dynamic system maintains cable tension despite micromotion, preventing the significant tension loss that occurs with static fixation methods.
Data Source
AI summary
A system, devices and methods are provided for facilitating stabilization of periarticular fractures. The system includes a compression plate and one or more of a cerclage cable for encircling the bone and securing the compression plate to the bone, a crimp lug for securing the cable in tension relative to the bone and/or a plate, and a supplemental plate coupled to the compression plate and adapted to receive bicortical or unicortical bone screws to further secure the compression plate relative to the bone. In addition, the system includes a cable tensioner for temporarily retaining the cable in tension and then applying a tension to the cable until a desired compression is effected between a plate and bone and while a cable retaining structure is secured to the cable to retain the applied tension on the cable. Also provided is a jig for use with plates for minimally invasive fracture stabilization.