Pauwels classification of femoral neck fractures - hip fracture

Pauwels' classification divides femoral neck fractures into three grades according to the degrees of the inclination of the fracture line, so called Pauwels' angle. The distinction between grade II and III is often misinterpreted. Moreover, as originally pointed by Pauwels, the distinction between grade I and II should be also based on the presence of a shearing force, which can be neutralized by impaction. Therefore, some fractures with more vertical fracture line (>30 degrees) may still be considered grade I. Similarly, the distinction between grade II and grade III fractures is based on the presence of free torque, that distracts the upper part of the fracture line. If present, the fracture should be classified as grade III.

Grade Pauwels' angle
Pauwels I <30 degrees
Pauwels II 30 - 50 degrees
Pauwels III >50 degrees

References:

1. Nowakowski, A. M., Ochsner, P. E., Majewski, M. Classification of femoral neck fractures according to pauwels: interpretation and confusion. J Biomedical Science and Engineering. 2010;3:638–43.
2. Pauwels, F. Der schenkelhalsbruch ein mechanisches problem. Z Orthop Ihre Grenzgeb. 1935;63.
3. Bartonícek J. Pauwels’ classification of femoral neck fractures: correct interpretation of the original. J Orthop Trauma. 2001 Jul;15(5):358–60
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  Pauwels classification of hip fractures - Pauwels angle, femoral neck