3D printed aiming device for equine proximal interphalangeal joint arthrodesis: Ex vivo study.

Overview

• This study evaluated the effectiveness of a 3D-printed titanium aiming device designed to assist in placing two transarticular screws during proximal interphalangeal joint (PIPJ) arthrodesis in horses using cadaver limbs.
• Results showed that for less experienced surgeons, the device improved accuracy, reduced surgery time, and decreased radiation exposure, while for expert surgeons, it mainly reduced the number of radiographs needed.

Background and Objective

• Proximal interphalangeal joint (PIPJ) arthrodesis is a surgery performed on horses to fuse this joint, typically involving the placement of transarticular screws to stabilize the joint.
• Correct screw placement is crucial for successful outcomes and can be challenging, especially for less experienced surgeons.
• The study aimed to test whether a customized, 3D-printed titanium aiming device could help surgeons, particularly novices, place these screws more efficiently and accurately.

Methods

• Study design: Ex vivo (outside the living organism) study using 40 cadaveric forelimbs from adult horses.
• Participants: Two surgeons performed the procedures:
  • A senior surgeon (experienced)
  • A first-year resident surgeon (inexperienced)
• Procedure:
  • Each surgeon performed 20 screw placements: 10 with the 3D-printed aiming device and 10 freehand (traditional technique without the device).
  • Two 5.5-mm transarticular screws were placed for PIPJ arthrodesis in each limb.
• Measurements recorded:
  • Duration of the procedure (in minutes)
  • Number of intraoperative radiographs (X-rays) taken
  • Final radiographs evaluated by a blinded, certified surgeon for:
    • Compliance with AO surgical principles
    • Symmetry and homogeneity of the screw construct
  • Accuracy of screw hole placement on the articular surface after implant removal.

Results

• For the inexperienced surgeon:
  • Procedure time decreased by 25% with the device (from 27.24 to 20.16 minutes).
  • Number of intraoperative radiographs reduced by 60% (from 6.1 to 2.1).
  • Accuracy score improved by 31% (mean score from 4.4 to 5.8).
  • Construct symmetry improved by 47% (score increased from 1.5 to 2.2).
  • All improvements were statistically significant (p < .01 for most, p < .05 for symmetry).
• For the senior surgeon:
  • The number of radiographs taken decreased by 58% (from 3.1 to 1.3), which was statistically significant.
  • No significant changes in procedure duration, accuracy, or symmetry were observed.

Conclusions

• The 3D-printed aiming device demonstrated clear benefits for less experienced surgeons by improving the speed, accuracy, and consistency of screw placement in PIPJ arthrodesis.
• For experienced surgeons, while procedure time and accuracy were already optimized, the device still reduced radiation exposure by decreasing the number of intraoperative radiographs.
• The device is a promising surgical tool that may help standardize and improve the quality of this technically demanding procedure, particularly during surgeon training.
• By enhancing the feasibility and repeatability of the transarticular screw placement, the device supports adherence to best surgical practices and could improve clinical outcomes in equine orthopedic surgery.