Objective To summarize the new research progress in distal interlocking screws of cephalomedullary nails for the treatment of intertrochanteric fractures. Methods Relevant domestic and foreign literature was extensively reviewed to summarize the static/dynamic types of distal interlocking screw holes, biomechanical studies, clinical studies and application principles, effects on toggling in the cavity, and related complications of distal interlocking screws.ResultsThe mode of the distal interlocking screw holes can be divided into static and dynamic. Distal interlocking screws play the role of anti-rotation, maintaining femur length, resisting compression stress, increasing torque stiffness, resisting varus stress, etc. The number of the screws directly affects the toggling of the main nail in the cavity. At present, regardless of whether long or short nails are used, distal interlocking screws are routinely inserted in clinical practice. However, using distal interlocking screws can significantly increase the duration of anesthesia and operation, increase fluoroscopy exposure time, surgical blood loss, and incision length. There is a trend of trying not to use distal interlocking screws in recent years. No significant difference is found in some studies between the effectiveness of dynamic and static interlocking for AO/Orthopaedic Trauma Association (AO/OTA) 31-A1/2 fractures. At present, the selection of the number and mode of distal interlocking screws is still controversial. When inserting distal interlocking screws, orthopedists should endeavor to minimize the occurrence of complications concerning miss shot, vascular injuries, local stress stimulation, and peri-implant fractures. Conclusion Distal interlocking screws are mainly used to prevent rotation. For stable fractures with intact lateral walls, long cephalomedullary nails can be used without distal interlocking screws. For any type of intertrochanteric fractures, distal interlocking screws are required when using short cephalomedullary nails for fixation. Different interlocking modes, the number of interlocking screws, and the application prospects of absorbable interlocking screws may be future research directions.
Objective To review and summarize the projections of radiographic images during cephalomedullary nailing fixation for intertrochanteric femoral fractures, and to propose a set of three projections as standard requirement in immediate postoperative fluoroscopy. MethodsPapers on intertrochanteric femoral fractures treated with cephalomedullary nailing fixation that published in a three-year period of 2021—2023 in four leading English orthopedic trauma journals were searched in PubMed. The presented radiographic pictures were identified and scrutinized as whether they were in standard anteroposterior and/or lateral projections of the implanted nails. The nonstandard presence percentage was calculated. Combined with clinical experience, the standard anteroposterior and lateral perspective images of femoral neck, the current situation of radiographic imaging in the operation of cephalomedullary nails, the literature analysis of nonstandard images, the impact of limb rotation on image interpretation, and the characteristics of anteromedial 30° oblique perspective were summarized and analyzed. Results The presence of nonstandard radiographic pictures is 32.1% in anteroposterior view and 69.2% in lateral view in leading orthopedic trauma journals. In cephalomedullary nailing fixation operation of intertrochanteric femoral fractures, it is reasonable to use the radiographic images of the implanted nails to represent the fractured head-neck, as the head-neck implant (lag screw or helical blade) is aimed to put into centrally in femoral head in lateral projection. Limb rotation or nonstandard projections produced distortion of images, which interfers the surgeons’ judgement of fracture reduction quality and the measurement of implant position parameters in femoral head (such as neck-shaft angle and tip-apex distance), and finally lead to a meaningless comparison with the accurate normal value. The 30° anteromedial oblique view from the true lateral (set as 0°) is a tangential projection of the cortices at the anteromedial inferior corner, which gives a clear profile for the determination of cortical apposition status and mechanical support. It is essential to get firstly the true standard lateral fluoroscopy of the nail (shown as a line), then rotate the C-arm to 90° and 30° to get anteroposterior and anteromedial oblique views, and use these three immediate postoperative radiographies as the baseline for evaluation of operative quality and follow-up comparisons. Conclusion As for real-time monitoring of surgical steps, intraoperative fluoroscopy follows the “Enough is Good” principle, but as for immediate postoperative data storage and basis for operative quality evaluation and baseline for follow-up comparison, it is recommended to obtain a set of three standard radiographic pictures in anteroposterior, true lateral, and 30° anteromedial oblique fluoroscopic projections.