Use of fluoroscopy in determining screw overshoot in the dorsal distal radius: a cadaveric study.

Purpose: To determine the ability of standard fluoroscopic imaging to assess whether screws placed from volar to dorsal during distal radius plating have penetrated the dorsal cortex of the radius.

Methods: Hard-copy digital images of cadaveric distal radii with screws of different lengths penetrating the dorsal cortex of the radius were shown to practitioners. The group included attending hand surgeons and hand fellows in training at multiple institutions. The participants were then asked to determine, from multiple images presented, whether the screws penetrated the dorsal cortex of the radius or were acceptable in length.

Results: Much more accurate assessment of screw positioning occurred with radial screw positions. Experienced practitioners showed higher accuracy when evaluating screws in any position. Both groups showed the least accuracy in evaluating screws in the ulnar column of the radius. For all evaluators, fluoroscopy was found to be 82% sensitive at detecting cortical penetration in the radial-most position, 77% sensitive in the central position, and 57% sensitive in the ulnar position. Evaluators with >3 years in practice were able to detect incorrect screw positions with 100% sensitivity in the radial-most position, 90% in the central position, and 75% in the ulnar position. Inexperienced evaluators detected incorrect screw positioning with 70% sensitivity in the radial position, 61% centrally, and 56% ulnarly.

Conclusions: Accurate placement of screws used with volar fixation devices is important to avoid prominent hardware, especially screws that may penetrate dorsally into tendon compartments. Printed image intensifier images have limited sensitivity for the diagnosis of dorsal cortical penetration of a volarly inserted screw, particularly among less experienced observers and for the evaluation of the most ulnar screw positions.