Tibial Insert Recess for Posterior Cruciate Ligament Protection
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Solution Overview
Problem
Artificial knee prostheses often lack stability due to the high likelihood of anterior cruciate ligament rupture, especially in patients over 45, making the posterior cruciate ligament crucial for stability, and existing protection devices are inadequate in preventing rupture and ensuring stability post-rupture.
Innovation Solution
A device with an anatomically contoured body featuring a hollow recess and raised edges to securely accommodate the posterior cruciate ligament, ensuring shape-matched assembly and stability, even in the event of rupture, by being adaptable for both movable and fixed tibiae inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cruciate retaining prosthesis is used to protect the posterior cruciate ligament, then knee stability is improved, but the risk of ligament rupture remains and can lead to prosthesis failure
Solution Approach 1:
The device creates a protective recess in the tibial insert that cushions and protects the posterior cruciate ligament from excessive forces before rupture can occur. The recess acts as a pre-prepared protective structure that absorbs and distributes ligament forces, preventing the harmful effect of rupture while maintaining knee stability.
Solution Approach 2:
The protective recess structure serves as an intermediary element between the ligament and the prosthesis components. It mediates the forces transmitted through the ligament, providing a transition zone that reduces stress concentration and prevents direct transmission of harmful forces that could cause rupture or prosthesis failure.
2Reliability
If the posterior cruciate ligament ruptures, then knee stability is compromised, but replacement surgery is required
Solution Approach 1:
By providing protective recesses during the initial prosthesis installation, the system prevents ligament rupture before it occurs. This beforehand protection eliminates the need for subsequent replacement surgery, maintaining knee stability and avoiding the complexity of secondary surgical interventions.
3Object-affected harmful factors
If a protective device is added to the prosthesis, then ligament protection is improved, but device complexity increases
Solution Approach 1:
The protective recesses are merged into the tibial insert structure itself, combining the protective function with the load-bearing surface. This integration avoids adding separate complex components while still providing effective ligament protection through the anatomically-contoured recesses.
Solution Approach 2:
Rather than making the entire prosthesis more complex, the protection is provided through localized recesses only where the ligament contacts the insert. This local quality approach provides targeted protection without unnecessary complexity in other areas of the prosthesis.
Data Source
Figure 1~2
Figure 3~5
AI summary
A device (1) for protecting the posterior cruciate ligament in knee prostheses, comprising a substantially elliptical body (2) provided with a recess (3) in its central portion, the recess (3) being provided with rounded edges (4, 5) on at least one side of the recess (3).