Traction images heavily influence lateral wall measurement in trochanteric hip fractures. A prospective study.

Introduction: hip fracture represents a global health problem, with a high morbidity and mortality rate and an increasing incidence. The treatment of trochanteric fractures is reduction and osteosynthesis, and implant selection depends mainly on the stability of the fracture and lateral wall competence. Lateral wall competence has gained relevance in recent years, which led to the modification of the AO/OTA classification. However, determination of lateral wall integrity is difficult from plain radiographs; the influence of images with traction on its measurement has not been evaluated.

Methods: prospective concordance study, emergency and post-traction radiographs of 65 patients with trochanteric fracture were evaluated by six orthopedic surgeons independently, measuring the lateral wall, classifying the fracture according to the AO/OTA 2018 classification and selecting the implant for osteosynthesis. A comparison of incompetent to intact lateral wall proportion between each image set was made. Secondary outcomes were the inter-observer correlation of lateral wall measurement and inter-observer agreement of classification and implant choice.

Results: the proportion of patients with an incompetent lateral wall in emergency x-ray was 37.43% (CI 95% 0.326-0.422), while the proportion in post-traction fluoroscopy was 15% (CI 95% 0.115-0.185), with a statistically significant difference (p < 0.001). 40.1% of patients with an incompetent lateral wall changed to an intact one. Inter-observer correlation for the lateral wall thickness was 0.399 (CI 95% 0.292-0.519) in emergency x-ray and 0.658 (CI 95% 0.564-0.748) in post-traction fluoroscopy, with a substantial agreement. Inter-observer agreement for the fracture classification was fair to moderate using emergency x-ray (κ 0.369 95%CI 0.330-0.408) and fair to moderate with post-traction fluoroscopy (κ 0.400, 95% CI 0.334-0.466).

Conclusion: traction images significantly change the measurement of the lateral wall in trochanteric fractures, changing from an incompetent to a competent wall in 40% of patients. The correct classification of trochanteric fractures is crucial to make the best decision when deciding which implant to use, and the measurement of the lateral wall is determinant in the actual AO/OTA classification. Therefore, traction images appear as necessary for correct decision-making.