Session II Foot and Ankle

Retrospective Study of Intra-Articular Calcaneal Fractures Using CT: The Anterior Anatomy

Alex Miric, MD, Brendan M. Patterson, MD

MetroHealth Medical Center, Cleveland, Ohio

Hypothesis: The primary fracture line of intra-articular calcaneal fractures frequently extends through the anterior half of the calcaneus. Although reduction of the posterior facet is heavily emphasized, the fracture line extends through additional articular surfaces anterior to the posterior facet, including the calcaneocuboid joint, and the anterior and middle facets.

Conclusion: The primary calcaneal fracture line passes through the calcaneocuboid joint in 57.8% of the cases. The anterior and middle facets are involved 26.7% and 8.6% of the time, respectively. Plain radiographs were found to be unreliable in detecting fracture line extension into the calcaneocuboid joint.

Material and Methods: Radiographs of 205 patients diagnosed with 220 calcaneal fractures at MetroHealth Medical Center from 1988 to 1995 were retrospectively reviewed. Plain radiographs and CT scans in both coronal and axial planes were reviewed in 116 cases (106 patients).

Results: Of the 220 fractures, 163 were intra-articular fractures, 30 (18.4%) tongue-type and 133 (81.6%) joint depression. All fractures studied by CT were grouped according to the Sanders classification as follows:

Class	# identified	Class	# identified	Class	# identified
1	5 (4.3%)
2A	51 (44.0%)	2B	15 (12.9%)	2C	4 (3.4%)
3AB	15 (12.9%)	3AC	17 (14.7%)	3BC	3 (2.6%)
4	6 (5.2%)

The extension of the primary fracture line was evaluated for all cases. The primary fracture line extended into the calcaneocuboid joint in 67 cases (57.8%), the anterior facet in 31 cases (26.7%) and the middle facet in 10 cases (8.6%). A distinct anterolateral fracture fragment was identified in 93% of the cases examined. However, plain radiographs failed to identify the distal extension of the primary fracture line in 47.8% of the cases. The incidence of anterior facet involvement was significantly greater in Sanders-type 3 fracture patterns (46.0%) than Sanders-type 2 (20%) (p<0.025). Calcaneocuboid joint and medial facet involvement were evenly distributed throughout all Sanders fracture categories.

Discussion: The surgical management of calcaneal fractures remains controversial. The Sanders classification emphasizes the importance of the posterior facet. While it is clear that the posterior facet is critically important and proper reduction is essential to good outcome, the anterior process also requires attention. Proper reduction of the anterolateral fracture fragment restores lateral length and calcaneal shape, helps to re-establish the relationship between the posterior facet and the anterior and middle facets, and guides reduction. This is only relevant if the fracture line travels through the anterior surfaces often enough to warrant attention. Our study found that this is indeed the case. The CT images indicate that the primary fracture line routinely extends distally, creating a relatively consistent anterior process fracture. Over half of all intra-articular calcaneal fractures exhibited a component through the calcaneocuboid joint, while over 1 in 4 cases had an anterior facet fracture. The primary fracture line, however, cannot be reliably determined by examination of the plain radiographs, and requires CT imaging.