by Bruce J. Sangeorzan, MD
Bruce J. Sangeorzan, MD, is associate professor of orthopaedic surgery, University of Washington, Harborview Medical Center.
The literature is full of suggestions for the treatment of calcaneus fractures. Yet it is possible to read hundreds of papers devoted to calcaneus fractures and still not know which to treat or how to treat them. Closed treatment with early motion is a moderately successful treatment that remains the standard to which new treatments must be compared. However, failure to seek alternatives to closed treatment would have us accept impairments beyond a standard that would be acceptable in other intra-articular weight-bearing joints. As in most orthopaedic conditions, no valid prospective randomized trial has been completed. In the absence of such a trial, we base treatment decisions on training, experience, retrospective studies and, most worrisome, the vagaries of third-party dictum.
Enthusiasm for open treatment has had ebbs and tides in the literature dating back to the late 1800s. Initial enthusiasm has often been followed by a full retreat when complications such as infection and amputation changed the risk/benefit ratio. The current high tide of support for open reduction and internal fixation (ORIF) began with the development of specialized instrumentation for fracture care by the AO group. Emile Letournel, MD, provided insight into anatomy and technique to apply these new tools to fractures of the calcaneus.
These questions remain, however: which fractures patterns require ORIF, which patients are suitable candidates, and who should treat them? This opinion will attempt to answer these questions using approximately .007 percent of the words devoted to calcaneus fractures in the literature during the last eight years.
The last question is the easiest to answer: an orthopaedic surgeon with great understanding of the anatomy, well versed in care of intra-articular fractures and amply experienced in the handling of tenuous soft tissues.
The answer to the second question is less concrete. However, the usual criteria apply for elective procedures done for quality of life: an active person with a reasonable life expectancy and without significant comorbidity such as peripheral vascular disease, severe systemic disease, or an inability to comply with post operative rehabilitation. Poor bone quality and threatened soft tissue envelope are relative contraindications.
To answer the first question we are forced to reason backwards from what we know leads to a poor result if untreated. Consistently poor outcomes result from several treatable factors: a wide heel with subfibular impingement; diminished height, as measured by Böhler's angle (which causes secondary derangement of the ankle joint when the talar body rotates downward toward the plantar surface of the foot); and derangement of the subtalar joint. The first two are part of the same anatomic process, i.e., displacement of the tuberosity relative to the sustentacular fragment upward and laterally along the primary fracture line.
Böhler's Tuber-Joint angle is one parameter by which the relative force absorbed by the bone is estimated. Given equivalent conditions-bone quality, position of the foot, direction of application of force-the greater the applied load, the greater the depression of the posterior facet and of Böhler's angle. This flattening of the calcaneus reflects the amount of energy imparted and becomes a mechanical derangement in its own right when the talus assumes a position of relative dorsiflexion. The widening of the heel occurs as a result of the lateral translation of the tuberosity and outward buckling of the lateral wall. There may be direct impingement against the fibula, compression or displacement of the peroneal tendons and lateral displacement of the weight-bearing surface. These two factors can be improved by manipulation of the tuberosity under some limited ideal circumstances. If these were all that counted, manipulative reduction and internal fixation would satisfy treatment criteria for many fractures.
However, displacement of the joint surface is an important parameter in dysfunction of the subtalar joint. It is difficult to address this problem without ORIF. Empirically, displacement of a weight-bearing joint surface in excess of 2 mm requires reduction. The three facets of the subtalar joint are all part of one joint surface, and fractures between them and among them are intra-articular. Though smaller than the posterior facet, that anterior/middle facets bear more weight per area and presumably are instrumental in function of the joint. There is some clinical and laboratory evidence that displacement greater than 2 mm may have significant adverse effects.
Some simple guidelines might be drawn from this information. Extra articular fractures may be treated closed unless the fracture interferes with the mechanics of the hind foot or prevents rehabilitation. Simple depressed fractures (i.e. single intra-articular fracture) with a joint step off of 2 mm or less can probably be safely treated with early motion. Intra-articular fractures displaced 3 mm or more and fractures with significant displacement leading to the mechanical problems cited above, are good candidates for ORIF. In addition, whenever the soft tissues are threatened by gross displacement of bone, some type of reduction should be performed. Most importantly, it is unlikely that a complex injury with so many variables can adequately be encapsulated with a few guidelines. The ultimate decision is made at the bedside when an experienced orthopaedic surgeon interviews and examines the patient, reviews the imaging studies, and employs his or her best judgment. The threshold for open treatment varies with the risk of the patient, which is, in turn, proportional to the skill and experience of the surgeon.
In summary, there is not an abundance of evidence that demonstrates ORIF provides better outcome than closed treatment in all displaced fractures. However, the results of closed treatment aren't good enough to accept as definitive care. Further, it is reasonable to assume that there are some circumstances in which ORIF is a better option. There are known anatomic factors associated with poor outcomes. The fracture patterns that include these are reasonable candidates for ORIF. Treatment options include closed treatment with early motion, manipulative reduction with percutaneous fixation, and ORIF. The appropriate treatment should be selected using the good judgment of the trained orthopaedic surgeon.