INTRAOPERATIVE IMAGING TO DETECT OCCULT PENETRATION OF SCREWS AFTER VOLAR PLATING OF DISTAL RADIUS FRACTURES: A CADAVERIC STUDY

Hardware prominence is one of the major established complications following volar plating of distal radius fractures. The purpose of this cadaveric study is to compare two conventional fluoroscopic imaging views (Carpal Shoot-Through [CST] and Dorsal Horizon [DH] views) with ultrasound to establish the best intra-operative imaging modality for surgeons to use to identify penetration of screws through the dorsal cortex and / or into the distal radioulnar joint. Twelve human cadaveric upper limb specimens were instrumented with distal radius variable angle locking plates and four distal locking screws from a volar approach. CST, DH views and ultrasound evaluations were compared to identify prominent screws. There were 6 surgeons divided into 3 groups of different clinical experience performing the evaluations. Sensitivity and specificity of detecting screw penetration along with the surgeon's confidence in each modality were established. CST view was the most sensitive in identifying the presence of dorsal screw penetration (100%) and absence of dorsal screw penetration (78%). DH view had the highest sensitivity in recognizing DRUJ screw penetration (89%). Ultrasound evaluation had the lowest sensitivity and specificity (28%, 56% respectively). The fellowship trained upper extremity surgeons had the highest sensitivity and specificity rate of 78% and 78% respectively. Surgeon's ability to perform as well as confidence in evaluating for screw penetration was highest with the CST view. CST view was found to be the best intra-operative imaging modality to “rule in” and “rule out” screw penetration through the dorsal cortex. DH view was most reliable in detecting DRUJ screw penetration. Clinical experience was determined to be an important factor for both dorsal cortex and DRUJ evaluation. Ultrasound evaluation had the lowest sensitivity and specificity in all categories, demonstrating that this not a reliable modality for surgeons without specific training in point-of-care ultrasonography.