[Application of improved carpal shoot through view in volar plate internal fixation of distal radius fractures].

Objective: To explore the application of improved carpal shoot through view (ICSTV) method in the treatment of distal radius fractures with volar plate internal fixation.

Methods: The clinical data of 67 patients with distal radius fractures who met the selection criteria between January 2020 and January 2023 was retrospectively analyzed. There were 30 males and 37 females with an average age of 53.6 years (range, 18-75 years). According to the AO/Orthopaedic Trauma Association (AO/OTA) classification, there were 25 cases of type B and 42 cases of type C. The time from injury to operation ranged from 2 to 6 days, with an average of 3.8 days. During the operation, bilateral cortical drilling was performed, and the length of the implanted screw was 1-2 mm shorter than that measured by the depth ruler. Standard anteroposterior and lateral (AAL) fluoroscopy and ICSTV fluoroscopy were performed after volar anatomic locking plate fixation, respectively. If the dorsal cortex of the distal radius was detected to be penetrated, the short screw was replaced and ICSTV fluoroscopy was performed again until no screw was penetrated. The detection rate of dorsal cortical screw penetration was compared between AAL fluoroscopy and ICSTV fluoroscopy. Postoperative CT scan was performed to confirm the presence or absence of dorsal cortical screw penetration.

Results: Intraoperative AAL fluoroscopy found 5 screws penetrating the dorsal cortex in 4 patients (6.0%), and ICSTV fluoroscopy found 19 screws penetrating the dorsal cortex in 15 patients (22.4%) including the above 4 patients, with a significant difference in the detection rate between the two fluoroscopy methods [ OR=0.267 (0.084, 0.845), P=0.018]; 15 patients were replaced with short screws during operation. At the same time, ICSTV fluoroscopy detected 2 screws penetrating into the distal radioulnar joint in 2 cases (3.0%), which could not be found in AAL fluoroscopy, and the direction of the screws was adjusted and replaced. All patients were reexamined by wrist CT within 3 days after operation, and no dorsal cortical screw penetration or screw penetration into the distal radioulnar joint was found. All the 67 patients were followed up 6-18 months, with an average of 11.3 months. Extensor tendon irritation occurred in 2 patients at 3 months after operation, and no extensor tendon rupture occurred in all patients during follow-up. All fractures healed well, and the healing time was 8-13 weeks, with an average of 10.8 weeks. There was no complication such as internal fixation loosening or fracture displacement. The Gartland-Werley score at last follow-up ranged from 0 to 15, with an average of 5.6.

Conclusion: ICSTV fluoroscopy can effectively detect occult dorsal cortical screw penetration of the distal radius that can not be revealed by AAL fluoroscopy.