Proximal Ulnar Closing Wedge Plate With Polyaxial Fragment Compression
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Solution Overview
Problem
Existing surgical plates are inadequate for performing proximal ulnar closing wedge osteotomy due to interference with the medial humeral epicondyle and ulnar coronoid process, limiting their effectiveness in correcting joint incongruence and preventing osteoarthritis in pet animals.
Innovation Solution
A plate with polyaxial securing screws and a compression system, allowing angulation and compression between bone fragments, designed to stabilize the ulna fragments post-osteotomy, ensuring the semilunate notch remains intact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing surgical plates are used for proximal ulnar osteotomy, then the procedure can be performed, but the plate interferes with the medial humeral epicondyle and ulnar coronoid process
Solution Approach 1:
The plate is divided into distinct zones: a proximal zone with holes for securing screws that can be positioned away from interfering structures, and a distal zone with the compression mechanism. This segmentation allows the plate to perform its function while avoiding interference with the medial humeral epicondyle and ulnar coronoid process.
Solution Approach 2:
The plate design utilizes three-dimensional positioning to resolve the interference problem. By configuring the plate at an appropriate angle and position on the ulna, the harmful interference with adjacent structures is avoided while maintaining the necessary compression function at the osteotomy site.
2Reliability
If a closing wedge osteotomy is performed on the distal ulna, then joint incongruity can be corrected, but it cannot address conformational incongruity in the proximal ulna
Solution Approach 1:
The plate is designed as a universal device that can be applied to proximal ulnar osteotomy, extending the applicability of closing wedge osteotomy technique from only distal ulna to also include proximal ulna cases. This enables treatment of conformational incongruity that cannot be corrected by distal osteotomy alone.
3Device complexity
If the plate design does not include polyaxial screws, then the structure is simpler, but the screws cannot be oriented in the desired direction for optimal fixation
Solution Approach 1:
The plate incorporates polyaxial screws that allow dynamic adjustment of screw orientation. The screws can be positioned at different angles relative to the plate, providing operational flexibility for optimal fixation while maintaining a relatively simple overall plate structure. This dynamic capability enables adaptation to varying anatomical requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective stabilization and compression of ulna fragments, maintaining joint integrity and preventing osteoarthritis progression by increasing the radius of curvature of the lunate notch.
Implementation Method 1
the lower part of the head (51) meets the ramp (141) on the inclined lateral edges of the hole (14), such that it causes a longitudinal displacement of the head (51) inside the hole (14), from the outside towards the inside, thereby generating a compression effect between the bone fragments
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a plate for proximal ulnar closing wedge osteotomy for pet animals, which when secured on top of the bone forms a connecting bridge between the two fragments into which the osteotomy (O) has divided the ulna (C), each of which is secured to the said plate by means of three screws, one of which is a compression screw (5) that is mounted in a hole (14) with an elongate slot that forms an inner ramp (141) running inwards from the distal to the proximal end of the plate (1), such that when the screw (5) is tightened, a compression effect is generated between the bone fragments of the distal and proximal part of the ulna, tending to close the wedge of the osteotomy (O); while the other securing screws (2, 3, 4, 6, 7) are of the polyaxial type in order to allow a certain range of angulation with respect to the plate (1) when secured.