Expandable Wedge Implant for In-Situ Flatfoot Correction
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Solution Overview
Problem
Existing orthopedic implants for correcting bone deformities, such as pes planus or flatfoot, require multiple trials to determine optimal wedge thickness, leading to bone deformation and increased risk of post-operative complications like implant subsidence and revision surgery.
Innovation Solution
Expandable orthopedic implants capable of continuous expansion, allowing surgeons to dial in the desired wedge thickness without the need for trial and insertion, minimizing damage to bone fragments and reducing the risk of revision surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple trial wedges are inserted and removed to determine optimal thickness, then the optimal wedge thickness can be determined, but bone deformation and cortical wall damage occur
Solution Approach 1:
The implant transitions from a static trial wedge to a dynamic expandable system. The implant is inserted in a collapsed state and then expanded in-situ to the desired thickness using an actuator mechanism driven by a drive screw, allowing continuous adjustment without removing and reinserting multiple trials
Solution Approach 2:
The implant is inserted in a collapsed preliminary state that causes minimal disturbance to the bone fragments. The final thickness is then achieved by expanding the implant in-situ, rather than inserting the final thickness directly which would cause cortical wall damage
2Length of moving object
If distraction is performed to insert a thicker wedge, then the desired correction can be achieved, but bone fragments surrounding the wedge are damaged or broken off
Solution Approach 1:
The implant is inserted in a collapsed preliminary state that causes minimal disturbance to the bone fragments. The final thickness is then achieved by expanding the implant in-situ, rather than inserting the final thickness directly which would cause cortical wall damage
Solution Approach 2:
The implant transitions from a static trial wedge to a dynamic expandable system. The implant is inserted in a collapsed state and then expanded in-situ to the desired thickness using an actuator mechanism driven by a drive screw, allowing continuous adjustment without removing and reinserting multiple trials
3Reliability
If revision surgery is performed to insert a thicker wedge, then lost correction can be recovered, but wound healing complications increase
Solution Approach 1:
The implant allows for intraoperative adjustment of thickness through expansion, eliminating the need for revision surgery. The actuator mechanism can be adjusted while the implant is in place to achieve the desired correction without removing the implant or making additional incisions
Solution Approach 2:
The implant provides its own adjustment capability through the actuator and drive screw mechanism. The surgeon can dial in the desired thickness by rotating the drive screw, which translates the actuator to expand the top endplate away from the bottom endplate, allowing the implant to self-adjust without external intervention or revision surgery
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
The expandable implants effectively stabilize bone deformities by medializing the portion of bone deformities, stabilizing the bone, and/or providing a fusion site for bone to grow. The implants are capable of being inserted into an osteotomy site and expanded to distract and stabilize the osteotomy space. The implants are capable of being expanded to distract and stabilize the osteotomy space. The implants are capable of being expanded to distract and stabilize the osteotomy site and stabilize the osteotomy site. The implants are capable of being expanded to distract and stabilize the osteotomy site and/or provide a fusion site for bone to grow. The implants are capable of being inserted into an osteotomy site and expanded to distract and stabilize the osteotomy space. The implants are capable of being expanded to distract and stabilize the osteotomy site and stabilize the osteotomy site. The implants are capable of being expanded to distract and stabilize the osteotomy site and/or provide a fusion site for bone to grow. The implants are capable of being expanded to distract and stabilize the osteotomy site and stabilize the osteotomy site. The implants are capable of being expanded to distract and stabilize the osteotomy site.
Implementation Method 1
a drive screw configured to move the actuator. Rotation of the drive screw translates the actuator to expand the top endplate away from the bottom endplate
Implementation Method 2
The arced ramps on the actuator mate with the angled ramps on the top endplate to achieve tangential surface contact at any degree of implant expansion
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3
AI summary
Expandable wedge implants and related methods. The expandable implant may include a bottom endplate, a top endplate pivotably connected to the bottom endplate, an actuator with curved ramps configured to mate with angled ramps on the top endplate, and a drive screw configured to move the actuator to thereby expand the top endplate relative to the bottom endplate. The expandable implants may be configured to correct pes planus or a flatfoot deformity using Evans and/or Cotton procedures during foot surgery.