Interference Screw with Orientation-Controlled Driver Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing interference screws used in ligament reconstruction surgeries occupy significant space within bone tunnels, limiting bone-to-ligament integration and causing incomplete absorption, which restricts the strength of the graft-ligament junction and may leave foreign material in the body.
Innovation Solution
An interference screw with an open helical coil design and a through bore featuring a controlling member that engages with a driver only in a specific orientation, allowing for precise alignment and insertion to minimize space occupation and enhance bone-to-ligament integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an interference screw is used to secure the graft ligament in the bone tunnel, then the graft ligament is firmly fixed in place, but the screw occupies significant space within the bone tunnel, limiting bone-to-ligament integration
Solution Approach 1:
The interference screw is divided into multiple segments or sections along its length, with each segment providing fixation function independently. This segmentation allows the screw to maintain structural integrity and fixation strength while reducing the overall volume occupied in the bone tunnel, thereby increasing space for bone-to-ligament integration.
Solution Approach 2:
The interference screw is constructed using porous or lattice-structured materials that provide mechanical strength and fixation capability while significantly reducing the material volume. The porous structure allows bone ingrowth through the screw, enhancing bone-to-ligament integration while maintaining the necessary fixation strength.
2Reliability
If a traditional interference screw is used, then the graft ligament is secured effectively, but the screw material may not be completely absorbed, leaving foreign material in the body
Solution Approach 1:
The screw material parameters are optimized to balance mechanical strength requirements with biodegradability. By adjusting material composition, crystallinity, molecular weight, and cross-linking density, the screw maintains sufficient strength for graft fixation while enabling complete or near-complete absorption over time, eliminating foreign material presence.
Solution Approach 2:
The interference screw is made from composite materials that combine biodegradable polymers with reinforcing agents or layered structures. This composite construction provides the necessary mechanical strength for reliable graft securing while the biodegradable components are gradually absorbed by the body, achieving both reliability and complete loss of substance.
3Ease of operation
If the interference screw is inserted without controlled orientation, then insertion is simpler, but the driver orientation cannot be confirmed, potentially compromising fixation quality
Solution Approach 1:
The interference screw incorporates asymmetric features such as non-circular cross-sections, asymmetric thread patterns, or directional grooves that provide inherent orientation control. These asymmetric elements engage with corresponding features on the driver, ensuring the driver can only be inserted in the correct orientation, thereby confirming proper alignment while maintaining ease of operation through intuitive insertion.
Solution Approach 2:
The screw design includes feedback mechanisms such as tactile clicks, visual indicators, or mechanical interlocks that confirm when the driver is properly oriented and engaged with the screw. This feedback provides real-time confirmation to the surgeon that correct orientation has been achieved, ensuring fixation quality without complicating the insertion process.
Data Source
AI summary
The present disclosure relates to an interference screw having a body with a proximal end, distal end, and longitudinal axis extending between thereinbetween. The screw further includes threads for fixing the screw into bone. The screw further includes a through bore defined by the body. The through bore extends between the proximal and distal ends along the longitudinal axis, and has a surface. The screw further includes a controlling member formed by the through bore surface. To install the screw into bone, a surgeon turns the screw with a driver that engages with the controlling member. The driver only engages the controlling member when it is in a driving orientation with respect to the controlling member. Advantageously, with this “one-way” engagement the surgeon can control and confirm the orientation of the driver without seeing the driver and/or screw.