TO THE EDITOR:
In “Coronal Shear Fractures of the Distal End of the Humerus” (78-A: 49–54, Jan. 1996), McKee et al. described the fracture as a “shear fracture ... that extended in the coronal plane across the capitellum to include most of the lateral trochlear ridge and the lateral half of the trochlea.” They indicated that this type of injury had not been described before. It seems more likely that most such coronal fractures of the capitellum extend into the trochlea. The authors should have indicated how many patients had the typical pre-reduction radiographs, shown in their article, that did not demonstrate extension into the trochlea and how these patients were managed.
We recently reported successful closed reduction of nine coronal fractures of the capitellum2. The pre-reduction radiographs were identical to those in the article by McKee et al. Contrary to what has been reported in the literature, closed reduction can usually be accomplished, and the reductions are stable. The duration of immobilization for our patients was shorter (three compared with four to six weeks), and the results were seemingly at least as good as those for the patients reported on by McKee et al.
Herbert Bloom, M.D.; Michael Coyle, M.D.: Department of Orthopedic Surgery, Robert Wood Johnson Hospital, New Brunswick, New Jersey 08901
Dr. McKee, Dr. Jupiter, and Dr. Bamberger reply:
We read with interest the recent contribution of Dr. Bloom and Dr. Coyle to the literature on coronal sheer fractures2. In response, we point out that, during the time that the six patients who had a coronal shear fracture were seen at our institutions, more than ninety patients were managed for an intra-articular fracture of the distal end of the humerus, including a number who had a so-called simple capitellar fracture with no extension into the trochlea.
We disagree that “most such coronal fractures of the capitellum extend into the trochlea.” In fact, a careful review of the literature suggests that substantial extension into the trochlea is uncommon and, when it does occur, often involves a separate trochlear fragment. The two most widely used classification schemes for capitellar fractures, the AO classification and the Bryan-Morrey classification1, clearly delineate fractures that are isolated to the capitellum.
Similarly, we disagree that their pre-reduction radiograph2 shows a clear so-called double-arc sign. While this is a matter of some subjective opinion, in order for the proper double-arc sign to be evident some rotation of the displaced fragment must occur, thus outlining the subchondral arc of bone of the capitellum and trochlear ridge in profile. This rotation, as seen in our Figure 1, is an integral part of the coronal shear fracture that is not seen on any of the radiographs in their series. In fact, it is this rotation, as the displaced fragment migrates proximally, that makes closed reduction of these fractures so difficult.
Our experience with coronal shear fractures of the distal end of the humerus has included patients who were referred for reconstruction of post-traumatic deformity and management of stiffness caused by malunion. These patients had been managed originally with closed reduction, which led to an unsatisfactory result because of healing of the intra-articular fragment in a displaced position. These patients were originally included in our series but were removed before final publication. Thus, our experience with this type of fracture suggests that closed treatment is not universally successful.
As Bloom and Coyle point out in their article2, “Multiple authors state that closed reduction is rarely successful” in the treatment of capitellar fractures in general. Our general experience with capitellar fractures is similar. While the technique used by Bloom and Coyle for the closed treatment of isolated, simple capitellar fractures is promising, it remains to be seen if their results with such treatment can be duplicated by other investigators. Direct comparison of patient outcomes would be facilitated by their use of an objective elbow-scoring system in the future.
While we strongly believe that open reduction and internal fixation remains the treatment of choice for coronal shear fractures of the distal end of the humerus, closed reduction as definitive treatment for isolated capitellar fractures without rotation may warrant additional investigation.
Michael D. McKee, M.D., F.R.C.S.(C): Upper Extremity Service, St. Michael's Hospital Orthopaedic Associates, 55 Queen Street East, Suite 800, Toronto, Ontario M5C 1R6, Canada
Jesse B. Jupiter, M.D.: Orthopaedic Hand Service, Massachusetts General Hospital, 14 Fruit Street, Boston, Massachusetts 02114
H. Brent Bamberger, D.O.: Orthopaedic Associates of Southwestern Ohio, 425 West Grand Avenue, Suite 1003, Dayton, Ohio 45405
1. Jupiter, J. B., and Morrey, B. F.: Fractures of the distal humerus in the adult. In The Elbow and Its Disorders, edited by B. F. Morrey. Ed. 2, pp. 356-357. Philadelphia, W. B. Saunders, 1993.
2. Ochner, R. S.; Bloom, H.; Palumbo, R. C.; and Coyle, M. P.: Closed reduction of coronal fractures of the capitellum. J. Trauma
, 40: 199-203, 1996.