Universal Cross-Pinning Guide for Non-Collinear ACL Tunnel Alignment
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Solution Overview
Problem
Current ACL replacement surgeries are complex due to anatomical differences between the tibia and femur, requiring different cross-pinning guides and tunnel alignments, which limits optimal positioning of replacement ligaments and increases surgical complexity and cost.
Innovation Solution
A universal cross-pinning guide with interchangeable guide pins allows for independent alignment and cross-pinning of femoral and tibial tunnels, enabling non-collinear tunnel axes for optimal anatomical placement of ACL grafts, using a single instrument set for both tibial and femoral tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If different cross-pinning guides are used for femoral and tibial tunnels, then anatomical differences between tibia and femur are addressed, but device complexity and surgical complexity increase
Solution Approach 1:
A single cross-pinning guide is designed to perform multiple functions by accommodating both femoral and tibial tunnel cross-pinning through interchangeable guide pins. The guide body includes a guide pin receptacle that can receive different guide pins (first guide pin for femoral tunnel, second guide pin for tibial tunnel), allowing one device to replace what would traditionally require two separate guides.
Solution Approach 2:
The cross-pinning guide is segmented into modular components including a guide body, guide pin receptacle, and interchangeable guide pins. This segmentation allows the guide pins to be swapped out depending on whether femoral or tibial cross-pinning is being performed, providing flexibility while maintaining a single unified device structure.
2Ease of operation
If femoral and tibial tunnels are required to be substantially aligned, then cross-pinning can be performed with simpler alignment, but optimal anatomical positioning of replacement ligament is limited
Solution Approach 1:
The system transitions from a static alignment requirement (tunnels must be substantially aligned) to a dynamic solution where the guide can be positioned and oriented independently for each tunnel type. The interchangeable guide pins and adjustable guide body allow the surgeon to adapt the guide orientation to match the specific anatomical geometry of each patient's femoral and tibial tunnels independently.
Solution Approach 2:
The cross-pinning guide allows for local optimization of each tunnel's positioning by using different guide pins configured for the specific anatomical characteristics of the femoral tunnel versus the tibial tunnel. Each guide pin can be designed with specific orientation and positioning characteristics tailored to its target tunnel, rather than requiring both tunnels to conform to a single alignment standard.
3Manufacturing precision
If separate tunnels are drilled for anteromedial and posterolateral bundles, then fully anatomic reconstruction is achieved, but surgical complexity and requirement for multiple cross-pinning guides increases
Solution Approach 1:
The single cross-pinning guide with interchangeable guide pins is designed to handle multiple tunnel cross-pinning scenarios, including single-bundle and double-bundle (anteromedial and posterolateral) reconstructions. By swapping guide pins, the same guide body can be used for cross-pinning grafts in femoral and tibial tunnels, as well as for multiple bundles, eliminating the need for separate guides for each tunnel type.
Data Source
AI summary
A method of providing a replacement anterior cruciate ligament (ACL) provides a tibial tunnel and at least one femoral tunnel for receiving the replacement ligament, the femoral and tibial tunnels not being colinear but rather in an orientation that more closely mimics the natural ACL. The femoral tunnel is formed through the anterior medial portal. A cross pinning guide having a femoral rod for insertion into the femoral tunnel, a spaced apart arc shaped track and a guide block having one or more bores aligned with the femoral rod whereby an instrument inserted through one of the bores creates a pilot hole for the cross pin which intersects the femoral tunnel and an appropriate angle thereof which avoids ligaments and other sensitive tissue can be selected by adjusting the guide block along the track.