Do we need to use the largest possible size of the Proximal Femoral Nail Anti-rotation (PFNA) in well-reduced intertrochanteric fracture? A study of distal PFNA intramedullary canal occupying ratio (ICOR).

PURPOSE: To assess the impact of the intramedullary canal occupying ratio (ICOR) on bone union and the stability of fixation in intertrochanteric fracture treatment using proximal femoral nail anti-rotation (PFNA) surgery.

METHODS

A retrospective analysis included 151 patients aged 60 years and above who underwent PFNA for unilateral intertrochanteric fractures between June 2020 and 2022. Patients were categorised into 3 groups based on ICOR percentiles (0.48-0.93). Bone healing was assessed using the Radiographic Union Score for Hip (RUSH) at 2, 6, and 12 weeks postoperatively. Fixation stability was assessed by comparing immediate and 3-month postoperative radiographs. Multivariate regression was used to assess the relationship between ICOR, RUSH scores, and fixation stability.

RESULTS

No significant differences in RUSH scores or stability measurements were found among the 3 ICOR-based groups. Multivariate regression showed no clear correlation between ICOR and RUSH scores, except for a statistically significant but not clinically relevant association with changes in neck-shaft angle. In contrast, RUSH scores were significantly associated with fracture severity according to the OTA/AO Classification.

CONCLUSION

ICOR was not a significant predictor of fracture healing or fixation stability. In uncertain cases regarding nail size, using a smaller nail was not linked to inferior radiographic or fixation-related outcomes.