Intraoperative Fluoroscopic Assessment of Reduction in Intertrochanteric Fractures: Which View Is More Reliable — AP or Lateral?
Intertrochanteric femoral fractures are the most common hip fractures in clinical practice and represent one of the three major osteoporotic fractures in the elderly. Conservative treatment requires prolonged bed rest, carrying high risks of pressure sores, pulmonary infection, pulmonary embolism, deep vein thrombosis, and other complications. It also imposes significant nursing burdens and prolonged rehabilitation, placing heavy socioeconomic strain on both families and society. Therefore, early surgical intervention, whenever tolerated, is the key to achieving favorable functional outcomes for hip fractures.
Currently, PFNA (Proximal Femoral Nail Antirotation) internal fixation is the gold standard for surgical treatment of hip fractures. Achieving a positive buttress reduction intraoperatively is critical to allowing early functional rehabilitation. Intraoperative fluoroscopy is routinely performed in both the anteroposterior (AP) and lateral views to evaluate the reduction of the anteromedial femoral cortex. However, discrepancies between the two views are not uncommon in practice (e.g., a positive buttress on the lateral view but not on the AP view, or vice versa). In such situations, how to determine whether the reduction is acceptable and whether revision is necessary remains a clinical challenge.
To address this, researchers from Shanghai East Hospital and Zhongshan Hospital analyzed the accuracy of AP and lateral fluoroscopic assessments in predicting reduction quality, using postoperative three‑dimensional CT as the reference standard.
Illustrations:
Figure (a, b, c): Schematic diagrams showing positive buttress (a), neutral buttress (b), and negative buttress (c) on the AP view.
Figure (d, e, f): Schematic diagrams showing positive buttress (d), neutral buttress (e), and negative buttress (f) on the lateral view.
Study Design and Methods
The study included 128 patients with intertrochanteric hip fractures. Intraoperative AP and lateral fluoroscopic images were independently evaluated by two surgeons (one junior, one senior) for the presence of a positive buttress or non‑positive buttress. The same images were re‑evaluated two months after the initial assessment. Postoperative CT scans were reviewed by an experienced attending professor, who determined whether the reduction was positive or non‑positive, serving as the gold standard for assessing the accuracy of the fluoroscopic evaluations.
The main comparisons were:
1. Intra‑ and inter‑observer reliability: Whether there were statistically significant differences between the two rounds of assessments for each observer, and between the junior and senior surgeons, as well as intra‑observer consistency.
2. Predictive reliability: Using CT as the reference, which view (AP or lateral) provided more reliable assessment of reduction quality.
Results
1. In both rounds of assessment, with CT as the reference, the two surgeons of different seniority showed no statistically significant differences in sensitivity, specificity, false‑positive rate, or false‑negative rate when using intraoperative X‑rays to evaluate reduction quality.
2. Regarding the reliability of reduction quality assessment, taking the first assessment as an example:
- When both AP and lateral views concurred (both positive or both non‑positive), the predictive reliability for CT‑confirmed reduction quality was 100%.
- When the AP and lateral views were discordant, the lateral view criterion demonstrated higher reliability in predicting CT‑confirmed reduction quality.
Illustrative case:
Figure showing a case with a positive buttress on the AP view but a non‑positive buttress on the lateral view — i.e., discordant findings between the two views.
Note: Three‑dimensional CT reconstruction allows multi‑planar assessment and serves as the reference standard for evaluating reduction quality.
Additional Clinical Insights
In addition to the positive and negative buttress concepts, the term "neutral buttress" (i.e., anatomical reduction) has also been used in previous reduction criteria for intertrochanteric fractures. However, due to limitations in fluoroscopic resolution and human visual discernment, a truly "anatomical reduction" is theoretically unattainable; in practice, all reductions are either slightly positive or slightly negative. The team of Dr. Zhang Shimin from Shanghai Yangpu Hospital (specific publication details not recalled by the author) previously suggested that positive buttress reduction may yield better functional outcomes than anatomical reduction in intertrochanteric fractures. Therefore, in light of the present study, the intraoperative goal should be to achieve a positive buttress whenever possible. If both AP and lateral views show positive buttress, the reduction is optimal. If only the lateral view shows positive buttress while the AP view is suboptimal, it may be acceptable to avoid unnecessary re‑manipulation.
Reference
Jia X, Zhang K, Qiang M, Chen Y. The accuracy of intra‑operative fluoroscopy in evaluating the reduction quality of intertrochanteric hip fractures. *Int Orthop.* 2020 Jun;44(6):1201-1208.