Background: The fracture healing assessment in subtrochanteric femoral fracture (SFF) is essential due to a high rate of implant failure and non-union. It requires an effective diagnostic tool for determining fracture union status. However, significant disagreement exists among clinicians for SFF union diagnosis, and no standardized method is available. Previous studies showed that radiographic union score (RUS) is reliable and highly correlated with fracture healing status.

Objective: To evaluate the reliability and diagnostic accuracy of the RUS method for assessing the fracture healing status in the treatment of SFFs.

Materials and Methods: The present study was a retrospective review study conducted on 44 SFFs. A panel of seven reviewers, which included five orthopedic surgeons and two musculoskeletal radiologists, assessed the radiographic healing of SFF based on both the RUS method and the physician impression method. The interobserver and intraobserver reliabilities were calculated using the intraclass correlation coefficient (ICC) and Cohen’s kappa coefficient. The correlation and diagnostic accuracy between RUS and the clinical union were also evaluated.

Results: The RUS method resulted in higher intraobserver and interobserver agreement compared to the physician impression method. Inter-rater agreements of the RUS method and physician impression method were moderate (ICC=0.60) and minimal (kappa=0.37), respectively. The RUS method had a higher correlation with clinical union outcome compared to the physician impression method in SFFs (AUC 0.908 versus 0.640). A RUS of 7 or more at 12 weeks had 88% sensitivity and 63% specificity for predicting clinical union outcome.

Conclusion: The application of the RUS method is reliable for determining the fracture healing status in SFFs and has better correlation with clinical union than the physician impression method. The RUS method may also be useful for predicting clinical union in SFFs. These results support the use of the radiographic scoring system for fracture healing assessment in SFFs.

Keywords: Hip fracture, Subtrochanteric fracture, Fracture healing assessment, Radiographic union, Clinical union, Physician impression

DOI: doi.org/10.35755/jmedassocthai.2020.11.10868

Received 11 December 2019 | Revised 3 March 2020 | Accepted 10 March 2020