To The Editor:
In their recent article, "Results of Internal Fixation of Pauwels Type-3 Vertical Femoral Neck Fractures" (2008;90:1654-9), Liporace et al. state that, to their knowledge, there are no large clinical series presenting the results of internal fixation of high-shear-angle fractures. In fact, there are a number of such clinical reports, involving a total of 1808 patients, which have investigated the relationship between the Pauwels grade and the occurrence of fracture-healing complications1-6. Essentially, these studies failed to find any notable association between fracture-healing complications and the Pauwels angle or grade.
The Pauwels classification, which is based on the theory that fractures with a vertical fracture line have a higher shearing force and therefore would be more likely to go on to nonunion, is a very misunderstood system. Some clinicians use it for all intracapsular fractures. Pauwels type-1 fractures are mainly undisplaced and impacted fractures, while Pauwels type-2 or 3 fractures are displaced. Given that clinical studies of the results of treatment of displaced fractures only have failed to find any difference in the occurrence of nonunion between the Pauwels grades for displaced fractures1-3,6, it is clearly simpler to classify fractures as displaced or undisplaced.
Even more problems with the Pauwels classification system exist. To my knowledge, there has been no study of interobserver variation; the angles measured will vary depending on the degree of rotation in which the radiograph is made. Many of the publications related to the Pauwels classification have used different angles to define the three types. Even the article by Liporace et al., with its elegant color drawing, fails to clarify this basic flaw. I assume they mean a Pauwels type 1 is an angle of <30°; a Pauwels type 2, an angle of 30° to 70°; and a Pauwels type 3, an angle of >70°.
My conclusion from reviewing the literature on the Pauwels classification is that it has no relevance in current clinical practice for the primary treatment of an intracapsular hip fracture. It should therefore be regarded as a subject of historical interest only. Regrettably, the paper of Liporace et al. has no clinical relevance.