A Targeting Arm for Interlocking Screws Reduces Radiation Exposure: Results of a Prospective Randomized Controlled...

To compare time, fluoroscopic utilization, and number of misses for placement of far interlocking screws in tibial and femoral nails using a targeting arm (Targeter) versus perfect circle technique (Control).

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Prospective randomized controlled trial.

Single-center, large, urban, level 1 trauma center.

Patients ≥18 years old with a tibia or femur fracture (AO/OTA 31A, 32, or 42) treated with an intramedullary nail from November 2022 to December 2023 were included.

The main outcome measures were number of fluoroscopy images taken and average time elapsed to place each far interlocking screw. The far interlocking screws were defined as the screws farthest from the insertion handle. Comparisons were made between the Targeter and Control cohorts in terms of number of fluoroscopy images taken and average time elapsed to place each far interlocking screw, and the number of misses.

Thirty-one patients were randomized to Targeter and 31 to Control. There were no significant differences between the Targeter and Control cohorts in patient sex (58.6% vs. 54.5% women, P = 0.75), age (range (20-90 vs. 18-91, mean 52.7 vs. 54.2, P = 0.81), BMI (mean 25.9 vs. 26.2, P = 0.66), AO classification (13.8% vs. 36.4% 31 A, 37.9% vs. 21.2% 32, 48.2% vs. 42.4% 42, P = 0.20), or number of open fractures (13.8% vs. 7.1%, P = 0.67) between the 2 cohorts. For the Targeter group, fewer images were used than Controls for the first (15.0 vs. 22.5, P = 0.002), second (11.5 vs. 18.0, P = 0.006), and combined first and second (25.0 vs. 39.0, P = 0.001) screws. There was no difference between the Targeter and Control cohorts in the time it took to place the first (6.3 vs. 7.3 minutes, P = 0.31), second (5.8 vs. 6.2 minutes, P = 0.63), or combined first and second (11.9 vs. 13.7 minutes, P = 0.63) screws. In the Control cohort, there was 1 missed screw (1.4%, n = 69). In the Targeter cohort, there were 3 missed screws (5.4%, n = 56), a 4-fold increase that did not reach statistical significance ( P = 0.31).

In this prospective randomized controlled trial, a targeting arm decreased the number of fluoroscopic images used for all far interlocking screws as compared with the perfect circle technique without a reduction in time. There was a trend toward increased misses in the Targeter cohort ( P = 0.31). Although the reduction in radiation exposure may have a cumulative beneficial effect during the course of a surgeon's career, the trend of increased misses with the Targeter should be taken into account.

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.