Dynamic Compression Plate with Integrated Cable Tensioner
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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 stabilization.
Innovation Solution
A system comprising a compression plate with cerclage cables and supplemental plates that allow for secure fixation to the bone using integrated cable securing structures and crimp lugs, enabling tensioning and retention of the cable without requiring separate instruments, and providing elasticity to maintain tension during healing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard plating with unicortical screws and cerclage cables is used, then fixation can be achieved around implants, but the procedure requires multiple separate instruments (temporary tension holder and cable tensioner) and complex操作步骤
Solution Approach 1:
The patent combines the temporary tension holder and cable tensioner into a single integrated instrument. The instrument features a body with a cable passage, a tensioning mechanism with a pulley and cable, and a locking mechanism all integrated into one device, eliminating the need for multiple separate instruments and simplifying the surgical procedure.
Solution Approach 2:
The integrated instrument performs multiple functions: it holds the cable under temporary tension, applies final cable tension, and locks the cable in place. The single instrument replaces what previously required two or more separate tools, making the device multi-functional and reducing procedural complexity.
2Reliability
If cerclage cables are used for fixation, then stable compression can be maintained, but any movement between the cable, plate and anatomy causes significant reduction in tension and release of compression
Solution Approach 1:
The patent employs a dynamic compression mechanism where the cable can move within a cable passage that has a rounded bottom. This allows the cable to self-adjust and maintain compression force even when there is movement between the plate, cable, and anatomy. The rounded passage acts as a mechanical cushion that preserves compression despite positional changes.
Solution Approach 2:
The rounded-bottom cable passage is designed in advance to accommodate potential movement. The curved geometry provides a mechanical cushion that absorbs the effects of movement before tension is lost, ensuring that compression is maintained even when the cable shifts position relative to the plate or bone.
3Strength
If bicortical screws are used for plate fixation, then strong fixation is achieved, but they cannot be used when implants block the medullary canal
Solution Approach 1:
The patent uses unicortical screws that engage only the lateral cortex of the bone, avoiding the need to pass through the medullary canal. This localized fixation approach provides sufficient strength for plate attachment while adapting to the presence of implants in the medullary space. The fixation strength is achieved through proper screw placement and cerclage cable tension rather than bicortical engagement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Facilitates stable fixation and healing of periarticular fractures by ensuring consistent compression between the plate and bone, reducing the need for bicortical screws and minimizing interference from implants, while allowing for adjustable tension and secure cable retention.
Implementation Method 1
The cable is drawn into tension to cause the desired compression of the plate against the bone
Implementation Method 2
an elastic member, such as a spring or other elastic member, that stretches in response to cable tension
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.