Implementation of a new navigated parallel drill guide for femoral neck fractures

Comparison of freehand technique and a novel laser-guiding navigation system in femoral neck-cannulated screw fixation: a randomized controlled trial

Cannulated screw fixation is essential in treating femoral neck fractures, and the widely used freehand technique has several limitations. Therefore, we designed a new laser-positioning and navigation system and compared its efficacy with that of the traditional freehand technique in the cannulated screw fixation of femoral neck fractures. This randomized controlled single-blind trial recruited patients with femoral neck fracture, who were treated using either the newly designed laser-navigation device or the freehand technique. In in-vitro experiments, using the femoral neck model, the laser group was better than the freehand group in terms of operation time (P = 0.0153) and radiation exposure time (P < 0.001). In in-vivo experiments, involving 30 patients (15 in each group), the laser group was better than the freehand group in terms of operation time (P < 0.001), radiation exposure time (P < 0.001), blood loss (P < 0.001) and first success rate (P = 0.03). There was no difference in visual analog scale score, Harris score, and fracture-healing time between the two groups. In conclusion, the novel laser-guiding navigation system resulted in shorter operation time, less radiation exposure, and higher first success rate compared with the freehand technique. Further qualified investigations with a larger number of patients and longer follow-up are required in the future.

Introduction of a guide based on a femoral neck section for fixation with multiple screws: a cadaveric study

BACKGROUND

The design and application of assisted instrumentation for internal fixation of femoral neck fractures with multiple screws are still evolving. A novel guide based on a femoral neck section was designed to improve the accuracy of screw placement, and its efficacy was evaluated.

METHODS

A guide based on a femoral neck section was designed for assisted fixation of femoral neck fractures with multiple screws. Femoral specimens from 10 adults (20 femurs) underwent assisted internal fixation for a femoral neck fracture with 3 cannulated screws using the new guide technique or conventional technique. The accuracy of screw orientation and entry point, the accuracy of optimal screw positioning, and drilling attempts, operative time, and fluoroscopy time were recorded.

RESULTS

Among all 20 specimens, 60 screws were inserted successfully. Screw parallelism, operative time, and fluoroscopy time showed no statistical difference between the new guide technique and conventional technique (P > 0.05). The accuracy of optimal screw positioning was determined by the contained screw area ratio, distance between screws, distance from the centre of the femoral neck section, distance between screws and the femoral neck cortex, and Drilling attempts were statistical significantly better (data in the first three were larger and in the latter two was smaller) with the new guide technique, than with conventional technique (P < 0.05).

CONCLUSIONS

This new, two-dimensional, fluoroscopy-assisted, percutaneous guide technique enables accurate and optimal screw positioning in internal fixation of femoral neck fractures, compared with conventional technique.

A new adjustable parallel drill guide for internal fixation of femoral neck fracture: a developmental and experimental study

Background

Internal fixation is one treatment for femoral neck fracture. Some devices and techniques reported improved accuracy and decreased fluoroscopic time. However, these are not widely used nowadays due to the lack of available special instruments and techniques. To improve the surgical procedure, the authors designed a new adjustable drill guide and tested the efficacy of the device.

Methods

The authors developed a new adjustable drill guide for cannulated screw guide wire insertion for multiple screw fixation. Eight orthopaedic surgeons performed the experimental study to evaluate the efficacy of this device. Each surgeon performed guide wire insertion for multiple screw fixation in six synthetic femurs: three times with the new device and three times with the conventional technique. The fluoroscopic time, operative time and surgeon satisfaction were evaluated.

Results

In the operations with the new adjustable drill guide, the fluoroscopic and operative times were significantly lower than the operations with the conventional technique (p < 0.05). The mean score for the level of satisfaction of this device was also statistically significantly better (p = 0.02) than the conventional technique.

Conclusions

The fluoroscopic and operative times with the new adjustable drill guide were reduced for multiple screw fixation of femoral neck fracture and the satisfaction of the surgeons was good.

Training femoral neck screw insertion skills to surgical trainees: computer-assisted surgery versus conventional fluoroscopic technique

BACKGROUND

: Femoral neck fractures are among the most common orthopaedic injuries impacting the health care system. Surgical management of such fractures with cannulated screws is a commonly performed procedure. The acquisition of surgical skills necessary to perform this procedure typically involves learning on real patients with fluoroscopic guidance. This study attempts to determine if a novel computer-navigated training model improves the learning of this basic surgical skill.

METHODS

A multicenter, prospective, randomized, and controlled study was conducted using surgical trainees with no prior experience in surgically managing femoral neck fractures. After a training session, participants underwent a pretest by performing the surgical task (screw placement) on a simulated hip fracture using fluoroscopic guidance. Immediately after, participants were randomized into either undergoing a training session using conventional fluoroscopy or computer-based navigation. Immediate posttest, retention (4 weeks later), and transfer tests were performed. Performance during the tests was determined by radiographic analysis of hardware placement.

RESULTS

Screw placement by trainees was ultimately equal to the level of an expert surgeon with either training technique. Participants who trained with computer navigation took fewer attempts to position hardware and used less fluoroscopy time than those trained with fluoroscopy. When those trained with fluoroscopy used computer navigation at the transfer test, less fluoroscopy time and dosage was used. The concurrent augmented feedback provided by computer navigation did not affect the learning of this basic surgical skill in surgical novices. No compromise in learning occurred if the surgical novice trained with one type of technology and transferred to using the other.

CONCLUSIONS

The findings of this study suggest that computer navigation may be safely used to train surgical novices in a basic procedure. This model avoids using both live patients and harmful radiation without a compromise in the acquisition of a 3-dimensional technical skill.

The accuracy and precision of computer assisted surgery in the assessment of frontal plane deviations of the lower extremity: a femoral fracture model

OBJECTIVES

Mechanical axis deviation of the lower extremity as a result of malreduction or malunion of fractures plays an important role in the development of arthritis. Therefore it is crucial to restore the limb alignment as accurate as possible. The purpose of this study was to evaluate the accuracy and precision of navigation in assessing isolated frontal plane (varus/valgus) deviations of the lower limb in a simulated fracture model of the femur.

MATERIALS AND METHODS

Three fracture models with ten specimens in each were created in femoral synthetic composite bones to simulate a subtrochanteric (AO/OTA 31-A1), mid-diaphyseal (AO/OTA 32-A3), and supracondylar (AO/OTA 33-A1) femur fracture. Each specimen was mounted on a custom holding device and registered with the navigation system. Eight custom-made aluminum wedges of varying angles (5 degrees -26 degrees ) were used to create varus/valgus angulations at the fracture site. After wedge placement, the frontal plane deformity was recorded and registered by the navigation system. The means and standard deviations for each navigated wedge angle were calculated and compared to the actual wedge angle using a one sample t test. A single factor ANOVA test was subsequently performed to see if the differences between the navigated mean angles in each fracture group were statistically significant. The level of significance was defined as P < 0.05.

RESULTS

None of the navigated mean angles were found to be significantly different from the actual wedge angles (P = 0.05-1.00). More specifically, the differences between the navigated mean angles and the actual wedge angles ranged from 0 degrees to 0.7 degrees . Furthermore, the differences between the navigated mean angles in each angle group were found to be statistically insignificant (P = 0.53-0.99).

CONCLUSION

The high accuracy and precision of navigation systems in determining frontal plane deformities of long bones can make them an invaluable tool for the exact reduction and realignment of lower extremity fractures.