SLR - August 2013 - Ansgar Olsen
Reference: Berberian W, Sood A, Karanfilian B, Najarian R, Lin S, Liporace F. Displacement of the sustentacular fragment in intra-articular calcaneal fractures. J Bone Joint Surg Am. 2013 Jun 5;95(11):995-1000. doi: 10.2106/JBJS.L.01498.
Scientific Literature Review
Reviewed by: Ansgar Olsen, DPM, PhD
Residency Program: Inova Fairfax Hospital
Podiatric Relevance: The "constant" or sustentacular fragment of a displaced calcaneal fracture has traditionally been thought to have a stable association with the talus and is used as a foundation for surgical re-association of calcaneal fragments. This study demonstrates that angulation, diastasis, and translation of the sustentacular fragment occur commonly with displaced intra-articular calcaneal fractures. The condition of the sustentacular fragment should therefore be considered when surgical approach to fixation of a displaced calcaneal fracture is planned.
Methods: One hundred displaced intra-articular calcaneal fractures from a level I trauma center over a five year period were examined using Computed tomographic (CT) scans. All CT scans were graded using Sanders classification and associated injuries were recorded. Measurement of angulation, translation, and gapping of the sustentacular fragment were examined and compared to control values from 10 nondisplaced calcaneal fractures. Clinical importance was assigned to middle facet fractures with at least 10 degrees of angulation or three millimeters of translation.
Results: The sustentacular fragment was found to be displaced in 42 percent of the calcaneal fractures. Twenty-five percent of the calcanei had angulation of the sustentacular fragment of at least 10 degrees. Twenty-four percent had translation of the middle facet greater than three millimeters. Twenty percent had diastasis of the middle facet. Twenty-one percent demonstrated an intra-articular fracture of the middle facet. In fractures involving more than 50 percent of the posterior facet, there was a significant increase in risk of angulation, translation, gapping and intra-articular fractures of the sustentacular fragment. Overall displacement of the sustentaculum was significantly associated with three and four part fractures of the calcaneus.
Conclusions: This study of CT scans of displaced calcaneal fractures calls into question the theory of a "constant" sustentacular fragment. Assuming limited involvement of the sustentacular fragment may affect the quality of reduction and patient outcome. Alternative surgical approaches may be appropriate for treatment of calcaneal fractures with sustentacular displacement.