Segmented Tibial Tray Spline Guide for Deep Flexion
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Solution Overview
Problem
Total knee replacements often result in pain during deep flexion due to inflammation caused by impingement of soft tissue by the implant, particularly at the extremes of knee movement, limiting the anatomic range of motion.
Innovation Solution
A modular tibial tray system with separate medial and lateral tibial inserts, a tibial tray configured with a track and spline for guiding femoral component movement, and a platform with a keel and aperture for ACL reattachment, designed to reduce impingement and facilitate anatomical motion without pain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional tibial tray system is used, then the implant provides basic knee replacement function, but it causes soft tissue impingement and inflammation during deep flexion
Solution Approach 1:
The tibial insert is divided into mobile and fixed portions that can articulate relative to each other. The mobile tibial insert moves independently on the fixed tibial insert, allowing the soft tissue to clear the implant components during deep flexion while maintaining basic knee replacement function.
Solution Approach 2:
The tibial insert system transitions from a static, fixed configuration to a dynamic, mobile configuration. The mobile tibial insert can move relative to the fixed portion, adapting its position during knee flexion to prevent soft tissue impingement while maintaining articulation function.
2Ease of operation
If the implant allows deep flexion, then the range of motion increases, but soft tissue impingement and pain occur at extreme positions
Solution Approach 1:
By segmenting the tibial insert into mobile and fixed portions, the system allows deep flexion through relative movement of the segments. The mobile insert can translate and rotate on the fixed insert, enabling greater range of motion without the soft tissue contacting the implant at extreme positions.
Solution Approach 2:
The mobile tibial insert acts as an intermediary between the fixed tibial insert and the surrounding soft tissue. It absorbs the movement demands during deep flexion, allowing the soft tissue to clear the implant components while maintaining the articulation function.
3Ease of operation
If a modular tibial tray system with mobile insert is used, then deep flexion without impingement is achieved, but the device complexity increases
Solution Approach 1:
While segmentation into mobile and fixed portions increases device complexity, it enables deep flexion capability. The modular design allows the tibial insert to be divided into separate components that can move relative to each other, providing the necessary degrees of freedom for deep flexion without impingement.
Solution Approach 2:
The mobile and fixed tibial insert portions are combined into a single articulated assembly that functions as one integrated unit during knee movement. This merging of components allows the complex modular system to operate smoothly with a single degree of freedom, reducing the practical complexity despite the multiple parts.
Data Source
AI summary
A tibial tray system includes a tibial tray configured for attachment to a surgically-prepared surface of the proximal end of the tibia. The tibial tray includes a track disposed in a generally A-P direction. The tibial tray system also includes a spline configured to engage the track and to be positionable in at least one location along the track. The spline includes a bearing surface that is configured to contact a femoral component of the knee prosthesis to guide movement of the femoral component during extension and flexion of the knee.