OTA 2006 Posters
Scientific Poster #43 Foot and Ankle
Reliability of Bohler's Angle on Lateral Radiographs of the Calcaneus
Anthony Sanzone, MD (n); Emily Benson, MD (n);
Carol Conroy, MPH, PhD (n); Michael Bongiovanni, MD (n);
Adnan Cutuk, MD (*); Paul Gerard, MD (n); Michael Mazurek, MD (n);
Aaron Osbourne, MD (n); Alexandra Schwartz, MD (n);
Jeffrey Smith, MD (n); Joel Smith, MD (n);
San Diego Association of Traumatologists (SDAT),
San Diego, California, USA
Purpose: For decades, the measurement of Bohler's angle has been used extensively to determine
the loss of height of the calcaneus when it is fractured. This angle has
been measured on lateral radiographs preoperatively to help guide treatment
and to generate prognosis. In the orthopaedic literature, it has been found
to be predictive of morbidity and of the need for late subtalar fusion.
It has also been used to compare treatment methods. The purpose of this
study was to determine the reliability of this measurement.
Methods: 24 lateral radiographs of the calcaneus were used for this
study. They were selected from 5 different hospital radiology departments
and consisted of a wide spectrum of injury. Some were mildly fractured,
some were severely comminuted, and some were postoperative films. Ten orthopaedic
surgeons (5 orthopaedic trauma fellowship-trained surgeons, 2 orthopaedic
surgeons with an interest in trauma, 2 current orthopaedic trauma fellows,
and 1 orthopaedic resident) were instructed to measure Bohler's angle on
each film with the goniometer of their choice. They were asked to complete
the task again after a few hours had passed and then a third time a few
hours after that. Thus, for each radiographic case the Bohler's angle was
recorded 3 times by each observer. These numbers were then averaged and
the range was examined to determine both inter- and intraobserver reliability.
Results: There was an average interobserver range of 20° for
each radiograph, with an average standard deviation of 4.6°. The Shrout-Fleiss
intraclass correlation for interrater reliability was found to be 0.87 (with
0 being no correlation and 1 being perfect correlation). As expected, the
intraobserver results were more consistent than the interobserver measurements.
The Chronbach coefficient alpha test for intrarater reliability was found
to be 0.98.
Conclusion/Significance: These results suggest that the measurement
of Bohler's angle is associated with an acceptable degree of statistical
reliability despite a wide range of clinical measurements. Understanding
of this limitation is important when using Bohler's angle for scientific
or predictive purposes.
If noted, the author indicates something of value received.
The codes are identified as a-research or institutional support; b-miscellaneous
funding; c-royalties; d-stock options; e-consultant or employee; n-no conflicts
disclosed, and *disclosure not available at time of printing.
·
The FDA has not cleared this drug and/or medical device for the use
described in this presentation (i.e., the drug or medical device is being
discussed for an "off label" use). · · FDA
information not available at time of printing.