OrthoAdjust - Shoulder Balancer
Lead Participant:
T.J.SMITH AND NEPHEW,LIMITED
Abstract
**Unmet Need**:Shoulder arthroplasty (SA) is a challenging procedure to perform, compared to knee and hip arthroplasties, in terms of optimizing implant seating and soft tissue balancing. Poor implant component seating in the glenoid predisposes the implant to deformation, and micromotion increasing the risk of loosening. Consequently, pre-setting the correct passive tension in the shoulder muscles is as important as achieving optimum orientation and fixation of the glenoid components. Currently, soft tissue tension and passive range-of-motion (ROM) during glenoid trialing are assessed manually using interchangeable shims to adjust the height of the trial, which is labour-intensive, and dependent upon surgeon experience.
**Our Solution:**OrthoAdjust uses a micro-solenoid ratcheting screw adjustable mechanism (<4mm high) that automatically adjusts the height, pitch and roll of the glenoid trial surface proving finer control of implant position than manual shims. OrthoAdjust simultaneously measures glenohumeral forces using sensors attached to cantilevers embedded in the outer cap, which help patient achieve unrestricted pain-free mobility.
**Approach:**OrthoAdjust is based upon the principle of a miniature "strap-wrench" using a pair of energized micro-solenoids that ratchet a wheel to rotate in a back-and-forth oscillatory action to either tighten or loosen a threaded screw. In turn, the wheel drives a leadscrew "leg" through a hole converting rotary into linear actuation. Three pairs of actuators create a stable tripod for adjusting the pitch and roll of the surface.
**Project team:**brings together a large (Smith+Nephew) and a small company (Marturion-Electronics) with combined expertise in medical devices, low-powered circuits and micro-actuators.
**Key Objectives/Focus**:Development of OrthoAdjust from a wired lab-demonstrator(TRL-4) to a wireless device tested on shoulder cadavers(TRL-6/7), which can be marketed as either a standalone intra-operative soft-tissue balancer or an adjunct for more complex robot-assisted procedures.
**Targeted Improvements:**
* Micro-solenoid (windings/diameter/current)
* Ratchet wheel (diameter)
* Lead screw (size/pitch)
* Optimum frictional forces;"pull" and "reset" mode,
* Trial size/scalability;extra-small,small,medium,large,
* On-board power/data management.
**Our Solution:**OrthoAdjust uses a micro-solenoid ratcheting screw adjustable mechanism (<4mm high) that automatically adjusts the height, pitch and roll of the glenoid trial surface proving finer control of implant position than manual shims. OrthoAdjust simultaneously measures glenohumeral forces using sensors attached to cantilevers embedded in the outer cap, which help patient achieve unrestricted pain-free mobility.
**Approach:**OrthoAdjust is based upon the principle of a miniature "strap-wrench" using a pair of energized micro-solenoids that ratchet a wheel to rotate in a back-and-forth oscillatory action to either tighten or loosen a threaded screw. In turn, the wheel drives a leadscrew "leg" through a hole converting rotary into linear actuation. Three pairs of actuators create a stable tripod for adjusting the pitch and roll of the surface.
**Project team:**brings together a large (Smith+Nephew) and a small company (Marturion-Electronics) with combined expertise in medical devices, low-powered circuits and micro-actuators.
**Key Objectives/Focus**:Development of OrthoAdjust from a wired lab-demonstrator(TRL-4) to a wireless device tested on shoulder cadavers(TRL-6/7), which can be marketed as either a standalone intra-operative soft-tissue balancer or an adjunct for more complex robot-assisted procedures.
**Targeted Improvements:**
* Micro-solenoid (windings/diameter/current)
* Ratchet wheel (diameter)
* Lead screw (size/pitch)
* Optimum frictional forces;"pull" and "reset" mode,
* Trial size/scalability;extra-small,small,medium,large,
* On-board power/data management.
Lead Participant | Project Cost | Grant Offer |
|---|---|---|
| T.J.SMITH AND NEPHEW,LIMITED | £126,379 | £ 63,190 |
Participant |
||
| INNOVATE UK | ||
| MARTURION ELECTRONICS LIMITED | £298,813 | £ 209,169 |
People |
ORCID iD |
| Darren Wilson (Project Manager) |