Patellar Tendon Displacement Prosthesis for Patellofemoral Pain
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Solution Overview
Problem
Existing treatments for patellofemoral conditions, such as patellofemoral pain and osteoarthritis, face challenges including invasive procedures, unsightly bumps, discomfort, and complications like Patella Baja, due to the limitations of current implant designs that fail to effectively redistribute forces and maintain anatomical alignment.
Innovation Solution
A prosthesis with a fixation portion mounted to the tibia, a spanning section extending cranially and laterally, and a displacement portion that engages the patellar tendon to displace it anteriorly, altering the angle and magnitude of forces on the patella, while minimizing interference with the infrapatellar fat pad and joint capsule, using a curved bearing surface to reduce caudal biasing and prevent Patella Baja.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a prosthesis displaces the patellar tendon anteriorly to reduce patellofemoral forces, then patellar pain and cartilage wear are reduced, but the prosthesis may create unsightly bumps and discomfort
Solution Approach 1:
The prosthesis employs a curved bearing surface instead of a flat or angular design. This curvature allows the prosthesis to conform to the natural anatomy of the patellar tendon and tibial plateau, distributing displacement forces more evenly and eliminating sharp edges that would create bumps or discomfort. The rounded profile maintains aesthetic appearance while providing effective anterior displacement.
Solution Approach 2:
The prosthesis design features different surface characteristics in different regions: a smooth curved bearing surface for tissue contact, a flat posterior surface for stable fixation to the tibial plateau, and specific geometric profiles for spanning sections. This localized optimization ensures each area performs its specific function while minimizing adverse effects.
2Reliability
If existing implant designs are used to treat patellofemoral conditions, then some therapeutic effect is achieved, but they fail to effectively redistribute forces and maintain anatomical alignment
Solution Approach 1:
The prosthesis is designed to accommodate dynamic changes in patellar tendon position and orientation during knee motion. The curved bearing surface and spanning sections allow the prosthesis to adapt to varying load conditions and joint angles, maintaining effective force redistribution throughout the range of motion while preserving natural anatomical alignment.
Solution Approach 2:
The prosthesis creates a counterbalancing effect by strategically positioning the displacement portion to generate anterior forces that counteract the caudal pull on the patella. This counterweight approach maintains anatomical alignment by balancing the forces acting on the patellofemoral joint during weight-bearing activities.
3Force
If the displacement portion extends under the patellar tendon to alter force angles, then patellofemoral forces are effectively redistributed, but interference with the infrapatellar fat pad and joint capsule may occur
Solution Approach 1:
The prosthesis is divided into distinct functional segments: a fixation portion for stable attachment to the tibial plateau, a spanning section that bridges across the joint space without penetrating deep structures, and a displacement portion that engages the patellar tendon. This segmentation allows force redistribution while minimizing interference with the infrapatellar fat pad and joint capsule by confining each component to its optimal location.
Solution Approach 2:
The spanning section acts as an intermediary element that transfers forces between the fixation portion and the displacement portion without requiring direct contact with sensitive structures like the fat pad or joint capsule. This mediator component enables effective force redistribution while maintaining a safe distance from vulnerable tissues.
4Ease of manufacture
If conventional implant designs are used, then surgical procedures are invasive, but alternative approaches may not provide sufficient force redistribution
Solution Approach 1:
The prosthesis combines multiple functions in a single device: fixation to the tibial plateau, spanning across the joint space, and displacement of the patellar tendon. This multi-functional design achieves effective force redistribution through a minimally invasive single-stage procedure, eliminating the need for separate invasive surgical steps while maintaining therapeutic effectiveness.
Data Source
AI summary
Prostheses, methods and related instrumentation for treating disorders of the knee by displacing a connective tissue acting on the patella to alter the location, angle or magnitude of forces exerted by the tissue on the patella so as to achieve a therapeutic effect in patellofemoral compartment of the knee.