Intraosseous Screw with Axial Cavity for Soft Tissue Anchoring
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Solution Overview
Problem
In soft tissue surgical repair procedures, the interposition of soft tissue between the intraosseous screw and bony cortex complicates screw purchase, leads to tunnel widening, and makes it difficult to select the correct screw size, resulting in either slippage or overtightening issues.
Innovation Solution
An intraosseous screw with a longitudinal axial cavity for soft tissue deposition and a retention member to facilitate anchoring, allowing the screw to be fully deposited in the bone structure before soft tissue insertion, with a window for tissue-bone contact and a suture system for secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft tissue is interposed between the intraosseous screw and bony cortex, then the soft tissue can be positioned within the bone tunnel, but the purchase of the threading on the bony cortex is compromised
Solution Approach 1:
The bone tunnel is divided into two functional zones: a proximal cortical region for screw threading engagement and a distal cancellous region for soft tissue deposition. The screw is segmented with a threaded portion for cortical purchase and a smooth shank portion for tissue deposition, allowing simultaneous achievement of secure fixation and tissue positioning without mutual interference.
Solution Approach 2:
A smooth shank portion acts as an intermediary element between the threaded screw body and the soft tissue. This intermediate section allows the soft tissue to be deposited and positioned within the bone tunnel without compromising the threading's engagement with the cortical bone, effectively mediating between the conflicting requirements of secure fixation and tissue accommodation.
2Reliability
If repeated attempts are made to gain necessary screw purchase, then the soft tissue can be positioned, but tunnel widening occurs
Solution Approach 1:
The bone tunnel is pre-formed with dimensions and characteristics optimized for both screw insertion and soft tissue deposition before the actual fixation procedure. This preliminary preparation ensures that the tunnel is appropriately sized to accommodate the soft tissue while still allowing the screw to achieve adequate purchase in the cortical bone without requiring repeated insertion attempts that would cause tunnel widening.
3Ease of manufacture
If an undersized intraosseous screw is selected, then the procedure can be performed with smaller hardware, but slippage of the soft tissue from the bone tunnel occurs
Solution Approach 1:
Different portions of the screw have different functional qualities: the proximal portion features threading for secure cortical engagement, while the distal portion provides a smooth surface for soft tissue deposition and retention. This local differentiation of screw properties allows the screw to simultaneously provide adequate retention for the soft tissue while maintaining appropriate size, preventing both slippage and the need for oversized hardware.
4Reliability
If an oversized intraosseous screw is selected, then adequate screw purchase is ensured, but the soft tissue wraps around the screw causing inaccurate tensioning
Solution Approach 1:
The screw is segmented into a threaded fixation portion and a smooth tissue-deposition portion. This segmentation allows the screw to achieve adequate purchase in the cortical bone through the threaded section while the smooth section prevents soft tissue wrapping, thereby ensuring both reliable fixation and accurate tissue tensioning without requiring oversized hardware.
Solution Approach 2:
The screw design changes key geometric parameters along its length: the threaded portion has elevated surface features for bone engagement, while the shank portion transitions to a smooth, uniform diameter that prevents tissue wrapping. This parameter variation along the screw's length enables simultaneous achievement of secure purchase and accurate tissue tensioning.
Data Source
AI summary
An intraosseous screw for deposit into a bone structure and retaining a soft tissue therein. The intraosseous screw includes a body and a retention member. The body defines an axial cavity in which soft tissue can be deposited and a window that permits the soft tissue to contact the bone structure in which the intraosseous screw is deposited. The retention member is positioned within the axial cavity and at least partially defines an opening through which a suture connected to soft tissue can pass to facilitate anchoring of the soft tissue within the axial cavity. The intraosseous screw can be combined with a passing suture, driver, and/or peg to provide a system for associating soft tissue with a bone structure. The intraosseous screw can be utilized in a method in which soft tissue is deposited into a bone structure after the interosseous screw is fully deposited in the bone structure.