Title: Pathoanatomy of Posterior Malleolar Fractures of the Ankle
Authors: Naoki Haraguchi, MD, Hiroki Haruyama, MD, Hidekazu Toga, MD and Fumio Kato, MD
Source: The Journal of Bone and Joint Surgery (American). 2006;88:1085-1092.
PODIATRIC RELEVANCE:
The knowledge of the pathoanatomy of posterior malleolar fractures is very important to the podiatric surgeon. Properly understanding the anatomy and biomechanics behind this type of injury is very important to guide proper treatment. The functional outcome following an ankle fracture with a posterior malleolar fragment is often poor and treatment remains controversial. The authors used computed tomography to clarify the pathologic anatomy of a posterior malleolar ankle fracture.
METHODS:
Fifty-seven consecutive patients with a unilateral ankle fracture with one or more posterior tibial fragments were managed from 1999-2003. All of the patients preoperative computed tomographic scans were reviewed to make two determinations. First, the ratio of the fragment area to the total cross-sectional area of the tibial plafond was determined. Secondly, the angle between the bi-malleolar axis and the major fracture line of the posterior malleolus was obtained. Each individual fracture was then categorized according to the location of major fracture line on the computed tomographic image at the level of the tibial plafond.
RESULTS:
Three categories of ankle fractures were created based on the computed tomographic analysis of fifty-seven patients. The first category consisted of the postero-lateral oblique type (thirty-eight fractures; 67%). The second category was the medial extension type (eleven fractures; 19%). Lastly, the third category was the small shell type (eight fractures; 14%). Interestingly, two of the eleven medial extension types extended to the anterior portion of the medial malleolus, and all others in this group consisted of two fragments. The postero-lateral oblique type fractures only comprised 11.7% of the cross-sectional area of the tibial plafond, while the medial extension type comprised 29.8% of the tibial plafond. There was much variation between the bi-malleolar axis and the major fracture line.
COMMENTS:
There appears to be large variability in the fracture lines associated with posterior malleolar fractures. In this study, as much as 20% of the posterior malleolar fractures extended into the medial malleolus. Some fragments involved almost the entire medial malleolus. Preoperative computed tomography may be justified based on the large variability in fracture configuration. The information obtained from this study supports the fact that it is very important to understand the pathoanatomy of posterior malleolar ankle fractures, and that computed tomography may be a very useful tool to the podiatric surgeon to determine the appropriate surgical approach.
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Disclaimer:
Scientific Abstract Monthly postings are submitted by podiatric surgical residents. The ideas presented are not the opinions of the American College of Foot and Ankle Surgeons (ACFAS), nor are they presented as facts. ACFAS presents this information without any warranty of any kind, expressed or implied, and is not liable for its accuracy nor for any loss or damage caused by the user's reliance on information obtained in these areas.