Hip implant optimization is increasingly receiving attention due to the development of manufacturing technology and artificial intelligence interaction in the current research. This study investigates the development of hip implant stem design with the application of lattice structures, and the utilization of the MATLAB regression learner app in finding the best predictive regression model to calculate the mechanical behavior of the implant’s stem based on some of the design parameters. Many cases of latticed hip implants (using 3D lattice infill type) were designed in the ANSYS software, and then 3D printed to undergo simulations and lab experiments. A surrogate model of the implant was used in the finite element analysis (FEA) instead of the geometrically latticed model to save computation time. The model was then generalized and used to calculate the mechanical behavior of new variables of hip implant stem and a database was generated for surgeon so they can choose the lattice parameters for desirable mechanical behavior. This study shows that neural networks algorithms showed the highest accuracy with predicting the mechanical behavior reaching a percentage above 90%. Patients’ weight and shell thickness were proven to be the most affecting factors on the implant’s mechanical behavior.

Background/Objectives: The mechanical stability of spinal instrumentation depends on adequate tightening of rod-securing screws. Although some implant systems provide recommended torque values, in many cases tightening remains surgeon-dependent. The objective of this study was to quantify the magnitude and variability of tightening torque applied by spine surgeons and to evaluate the influence of handling technique on torque generation. Methods: A thoracolumbar spine model instrumented with pedicle screws was used in an experimental setup. Twenty-two spine surgeons from six institutions performed a total of 220 screw-tightening procedures using a standard surgical screwdriver. Tightening torque was indirectly determined from measured loosening torque based on previously established calibration ratios. Hand usage, hand position, and surgeon orientation relative to the construct were recorded. Statistical analysis was performed using two-tailed Student’s t-tests with a significance level of 0.05. Results: The mean applied tightening torque was 4.52 Nm, with considerable inter-individual variability. Two-handed tightening resulted in significantly higher torque compared to single-hand techniques (p < 0.05). Screws tightened from the contralateral side relative to the surgeon were subjected to significantly higher torque (4.79 Nm vs. 4.25 Nm, p < 0.05). No clear association was found between institutional practice and applied torque magnitude. Conclusions: Substantial variability exists in the tightening torque applied by spine surgeons, and surgical technique significantly influences torque generation. These findings highlight the importance of standardized torque application and support the use of torque-limiting instruments to improve consistency in spinal implant fixation.

Background/Objectives: The mechanical performance of spinal instrumentation depends on appropriate fixation of rod-securing screws. Although manufacturer-recommended torque values and torque-limiting instruments are widely used in spinal surgery, the contribution of surgeon-related factors to manually applied tightening torque remains insufficiently characterized. This study aimed to quantify the magnitude and variability of tightening torque applied by spine surgeons and to investigate the influence of handling technique and surgeon orientation on torque generation. Methods: A thoracolumbar spine model instrumented with pedicle screw–rod constructs was used in an experimental setup. Twenty-two spine surgeons from six institutions performed a total of 220 screw-tightening procedures using a standardized manual screwdriver setup. Tightening torque was estimated from measured loosening torque using a previously established calibration relationship. Hand usage, hand position, and surgeon orientation relative to the construct were recorded. Statistical analyses were performed to compare torque values between different handling conditions. Results: The mean estimated tightening torque was 4.52 Nm, with considerable inter-individual variability among surgeons. Two-handed grip produced significantly (p = 0.006) higher torque (5.76 ± 1.46 Nm) compared to thumb-downward (3.47 ± 1.19 Nm). Among the univariate linear regression analyses, only the two-handed grip technique showed a significant association with higher fastening torque (B [95% CI]: 1.88 [0.56; 3.21], p = 0.008). The other factors (age, height, weight, experience) did not show a significant relationship. Conclusions: Manual tightening torque during spinal instrumentation shows substantial variability among surgeons and is influenced by handling technique and surgeon position. These findings demonstrate the importance of considering human factors in biomechanical evaluations of spinal fixation procedures. Further studies are required to determine the clinical significance of this variability.