To The Editor:
We note in figure 1 in the paper by Dimakopoulos et al.(1) that what the authors use as an example of a 4 part humeral head fracture is in fact a three part fracture). This mistaken classification may account in part for their pleasant surprise at the low prevalence of avascular necrosis they encountered. Three-part fractures are less likely than four part fractures to interrupt the principle blood supply to the head, i.e. the anterior circumflex artery. In contrast, in four part fractures, which we characterize as a subtype of a "Shield" fracture, both the greater and lesser tuberosity are detached and the main blood supply coming up the biceps groove is potentially disrupted.
This type of misclassification is common (2-5) when using the Neer or other classification systems that are based only on two dimensional x-rays. In contrast, using a 3-D classification system(6) allows a global evaluation of the fracture. and helps to avoid classification errors. Figures 3A and 3B (below) illustrate a 3 part valgus impacted injuries viewed in this way.
In a study of 63 complex fractures of the proximal humerus(7) we observed that three part valgus impacted injuries are more common than four part valgus impacted fractures. The key view for telling these two fractures apart is the 3D overhead view with the scapula removed. In three part fractures with this view one notes that the greater tuberosity alone, with or without comminution, is detached from the head. Occassionally, one may be fortunate to get a similar view with simple axillary X-ray, as the authors' have provided us in their Fig.4(see figure 1, below) – but such good luck is unusual in an acute fracture situation; in contrast,the 3D reconstruction gives this view consistently.
We recommend that surgeons use 3D studies to better understand of the type of fracture. Advance knowledge of the major fracture lines helps avoid ideopathic damage which sometimes results from limited surgical exposure.
Fig. 1. Modification of the authors' Fig. 4 (p. 1706) demonstrates this to be a 3, not a 4 part fracture. Note that the lesser tuberosity is intact while in a 4 part fractures the lesser tuberosity is by definition separated from the head.
Fig. 2. A 3D classification system demonstrates the actual anatomy of 3 Part, 4 Part ("Shield" injuries) and Isolated Greater Tuberosity fractures with which this article is concerned.
Fig. 3A and 3B. Examples of 3 part valgus impacted injuries seen in "fracture wheel" format. With views from four different directions, fractures can usually be accurately placed in a 3D classification system. 3A shows severe valgus displacement; 3B is less severe, similar to that shown by the authors' in their Fig. 4 example (our Fig. 1)..."B" is in bicipital groove.
The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families 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 authors, or a member of their immediate families, are affiliated or associated.
References:
1. Dimakopoulos P, Kasimatis G, Panagopoulos A. Transosseous suture fixation of proximal humeral fractures. J Bone Joint Surg Am 2007;89:1700-1709.
2. Brien H, Noftall F, MacMaster S, Cummings T, Landells C, Rockwood P.Neer's classification system: a critical appraisal. J Trauma 38: 257-260, 1995.
3. Burstein AH, (ed). Fracture classification systems: do they work and are they useful? Bone and Joint Surg Am 78: 1371-5, 1996.
4. Sidor M, Zuckerman J, Lyon T, Koval K. Cuom F, Shoenberg N. The Neer classification system for proximal humeral fractures: An assessment of interobserver reliability and intraobserver reproducibility. J Bone and Joint Surg Am 75:1745-1750, 1993.
5. Siebenrock K, Gerber C. The reproducibility of classification of fractures of the proximal end of the humerus. J Bone and Joint Surg Am 75 :1751-1755, 1993.
6. Edelson G, Kelly I, Vigder F, Reis ND. A three-dimensional classification for fractures of the proximal humerus. J. Bone Joint Surg Br. 2004;86B:413-25.
7. Edelson G, Safuri H, Salameh Y, Vigder F, Militianu D, Natural history of complex fractures of the proximal humerus using a 3-demensional classification system. Accepted for publication. J. Shoulder and Elbow Surg.
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