Predicting mechanical complications in proximal femoral nailing for elderly patients: a radiological scoring system based on a single-centre retrospective cohort with 586 cases.

Background: Proximal femoral nailing (PFN) is a preferred treatment for intertrochanteric femoral fractures in elderly patients due to its minimally invasive nature and early mobilisation benefits. However, mechanical complications such as implant failure, cutout, and reduction collapse remain significant challenges. This study introduces the targeted surgical score (TSS), a novel scoring system designed to predict and mitigate mechanical complications by evaluating modifiable surgical factors.

Methods: A retrospective analysis of 586 patients aged 65 and older treated with PFN between 2015 and 2022 was conducted. Data on demographic characteristics, fracture classifications, and surgical parameters were collected. Radiographic assessments included tip-apex distance (TAD) and lag screw positioning for implant placement quality, medial and anterior cortical support (MCS and ACS), and fracture alignment in both AP and lateral planes for reduction quality. Each parameter was scored, resulting in a cumulative TSS ranging from 0 to 8. Logistic regression and ROC curve analysis were performed to evaluate the predictive capacity of TSS.

Results: The average TSS was 4.06 ± 2.22 in the complication group and 6.14 ± 1.56 in the non-complication group (p < 0.001). A one-point increase in TSS was associated with a 44.9% reduction in complication risk (OR 0.551; p < 0.001). Independent risk factors included lag screw placement (non-central superior quadrants), inadequate cortical support in AP and lateral planes (MCS and ACS), and TAD (≥ 25 mm). The TSS demonstrated relatively good discriminative ability with an AUC of 0.768.

Conclusion: TSS may aid in predicting and mitigating mechanical complications while potentially guiding surgical applications in PFN, but further prospective multicentre validation is required. While certain parameters of TSS could be considered intraoperatively, its full implementation may be more practical for postoperative risk assessment.