Bedri Karaismailoglu, Omer Subasi, Wei-Shao Tung, Burak Ozturk, Ekrem Demirci, Arın Celayir, Baran Suat Sevgil, Fırat Kargın, Önder Aydıngöz, Nuri Aydın, Christopher W. DiGiovanni, Soheil Ashkani-Esfahani
Acta Orthopaedica et Traumatologica Turcica - 2025;59(6):368-373
Objective: To evaluate the accuracy and fluoroscopy shot count of a novel skin-matched, patient-specific Instrument (PSI) for subtalar arthrodesis compared with the conventional freehand technique in a cadaveric setting. Methods: Twelve cadaveric specimens were randomized into PSI-guided (n = 6) and freehand (n = 6) groups, with preoperative computed tomography scans used to design 3D-printed guides. Each PSI incorporated 2 pre-angled cannulated sleeves to allow optimal guidewire placement from the calcaneus into the talus. Outcomes included fluoroscopy usage, number of wire placement attempts, angular deviation between planned and actual wire trajectories (assessed in sagittal, coronal, and axial planes), and linear deviations at entry (calcaneal) and distal (talar) points. Statistical analysis used the Mann-Whitney U and Wilcoxon signed-rank tests with significance set at P < .05. Results: Fluoroscopy usage was significantly lower in the PSI group (median 3.0 [interquartile range, IQR 3.0-6.0]) compared with the freehand group (17.0 [15.3-18.8]; P = .009). Similarly, the number of attempts was reduced in the PSI group (2.0 [2.0-2.8]) versus the freehand group (6.0 [5.3-6.8]; P = .009). Angular deviation from the preoperative plan was low (median 3.0 derece [IQR 1.8 derece-4.7 derece]), indicating high trajectory fidelity. Linear deviation at the calcaneal entry point was minimal (median 0.9 mm [IQR 0.4-1.2 mm]), whereas greater variability occurred distally at the talar point (median 3.6 mm [IQR 2.0-5.1 mm]), remaining within clinically acceptable limits. Conclusion: The use of a skin-matched PSI for subtalar arthrodesis significantly reduced the number of fluoroscopy shots and wire placement attempts while ensuring high accuracy of guidewire trajectory. These findings support the potential of 3D-printed PSIs to improve surgical precision, suggesting clinical applicability for subtalar arthrodesis and related hindfoot interventions.
