JBJS -- Letters to the Editor for Liporace et al., 90 (8) 1654-1659

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Scientific Articles:
Frank Liporace, Robert Gaines, Cory Collinge, and George J. Haidukewych
Results of Internal Fixation of Pauwels Type-3 Vertical Femoral Neck Fractures
J Bone Joint Surg Am 2008; 90: 1654-1659 [Abstract] [Full text] [PDF]

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Dr. Haidukewych and colleagues respond to Dr. Parker: George J. Haidukewych (15 September 2008)

The Pauwels classification has no relevance for current practice: Martyn J Parker (15 September 2008)

Dr. Haidukewych and colleagues respond to Dr. Parker 15 September 2008

George J. Haidukewych,
Orthopedic Traumatology and Adult Reconstruction
Florida Orthopedic Institute
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Re: Dr. Haidukewych and colleagues respond to Dr. Parker

docgjh{at}aol.com George J. Haidukewych

I appreciate Dr. Parker's comments on the difficulty of measuring the Pauwels' angle, and understand the lack of literature on the interobserver reliability of the classification. I am concerned, however, that Dr. Parker feels that our data are not clinically relevant. I must point out that our series is the largest contemporary multi-center study of the "worst case scenario", most vertical femoral neck fractures treated with modern internal fixation devices. We chose to study these, since we felt that it is relatively simple to determine verticality over 70 degrees, as compared to the lower shear angles of 40 or 50 degrees, for example. Also, this cohort would be most likely to elucidate any differences in performance of various fixation strategies, since, theoretically, these fractures would experience the most shear.
Our overall nonunion rate was about fourfold higher than recent nonunion rates reported in series that did not sub-analyze shear angle. Our patient population was young, implying good bone quality, and we had a high rate of early, accurate reductions. Although we did not demonstrate a significant difference between fixed angle devices and screws alone, the nonnunion rate for screws alone was 19%. We consider a nonunion rate of 19% in a relatively young cohort very clinically relevant. We concede that the ideal fixation strategy has not been defined, however, Dr Parker must admit that a nonunion in about one in five young patients is clinically relevant. Anecdotally, in our practices, when we see a femoral neck nonunion in a younger patient, the typical clinical scenario involved a very vertical fracture that was treated with screws alone. We are aware that other centers are using anti-glide plates applied through an anterior approach to neutralize shear in vertical fractures.
Dr. Parker's series in 1998 evaluated the utility of the Pauwels' angle in predicting outcome in 335 patients with femoral neck fracture. However, it should be noted that there were only 8 patients with displaced fractures with shear angles of over 60 degrees in that series, and half went on to nonunion. Making conclusions on high shear angle fractures based on only 8 cases is impossible. Also, compiling data from the literature of the 1960's and 1970's and making conclusions from that pooled data is not relevant to modern fracture management, cannulated screws, fluoroscopy, and the understanding of the importance of reduction quality and timely fixation.
Obviously, further research is necessary to determine the ideal fixation strategy, but we still contend that Pauwels' grade three high shear angle fractures are problematic to treat and result in a nonunion rate that is substantially higher than historical controls. The Pauwels' classification may not be perfect, but, we maintain that fracture verticality matters.

The Pauwels classification has no relevance for current practice 15 September 2008

Martyn J Parker,
Hospital doctor
Peterborough and Stamford Hospital NHS Foundation Trust
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Re: The Pauwels classification has no relevance for current practice

Martyn.Parker{at}pbh-tr.nhs.uk Martyn J Parker

In their recent article, Liporace and colleagues[1] state that to the best of their knowledge, there are no large clinical series presenting the results of internal fixation of high shear angle fractures. In fact, there are number of such clinical reports, involving a total of 1808 patients, that have studied the relationship between the Pauwels grade and the occurrence of fracture healing complications.[2-7] Essentially these studies fail to find any notable association between fracture healing complications and the Pauwels angle or grade.
The Pauwels classification, based on the theory that those fractures with a vertical fracture line will have a higher shearing force and therefore be more likely to go onto non-union is a very misunderstood classification. Some clinicians use it for all intracapsular fractures. Pauwels grade 1 fractures are mainly undisplaced and impacted fractures,while Pauwels grade 2 or 3 fractures are displaced. Given that clinical studies of the results of just displaced fractures have failed to find any difference in the occurrence of non-union between the Pauwels grades for displaced fractures[2,3,4,7] it is clearly simpler to just classify fractures as displaced or undisplaced.
Even more problems with the Pauwels classification system exist. There are no studies of inter-observer variation; the angles measured will vary depending on the degree of rotation in which the x-ray is taken. Many of the publications related to the Pauwels classification use different angles to define the three grades. Even the article of Liporace et al.(1) with its elegant colour drawing, fails to clarify this basic flaw. I assume they mean a Pauwels 1 is an angle of less than 30 degrees, Pauwels 2, 30-70 degrees and Pauwels 3, more than 70 degrees.
Our 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 and colleagues[1] has no clinical relevance.
The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the author, or a member of his immediate family, is affiliated or associated.
References
1. Liporace F, Gaines R, Collinge C, Haidukeqych GJ. Results of internal fixation of Pauwels type-3 femoral neck fractures. J Bone Jong Surg Am. 2008;90:1654-9.
2. Barnes R, Brown JT, Garden RS, Nicoll EA. Subcapital fractures of the femur: a prospective review. J Bone Joint Surg Br. 1976;58-B:2-24.
3. Brown JT, Abrami G. Transcervical femoral fracture: a review of 195 patients treated by sliding nail-plate fixation. J Bone Joint Surg Br. 1964;46-B:648-63.
4. Cassebaum WH, Nugent G. Predictability of bony union in displaced intracapsular fractures of the hip. J Trauma. 1963;3:421-4.
5. Crawford HB. Conservative treatment of impacted fractures of the femoral neck: a report of fifty cases. J Bone Joint Surg Am. 1960;42-A:471 -9.
6. Flatmark AL, Lone T. The prognosis of abduction fractures of the neck of the femur. J Bone Joint Surg Br. 1962;44-B:324-7.
7. Parker MJ, Dynam E. Is Pauwels classification still valid? Injury. 1998;29:521-3.