We will be performing site maintenance on AAOS.org on February 8th from 7:00 PM – 9:00 PM CST which may cause sitewide downtime. We apologize for the inconvenience.

Fig. 1 Tibial widening was calculated as a ratio of femoral width over tibial width.
Courtesy of Bruce Ziran, MD

AAOS Now

Published 3/1/2012
|
Maureen Leahy

Study Seeks Compartment Syndrome Predictors

Clues include displacement, severity in tibial plateau fractures

Compartment syndrome is a serious condition that is difficult to diagnose; typically, orthopaedic surgeons must rely on clinical assessment and compartment pressure measurements. Study data presented at the 2012 AAOA Annual Meeting, however, indicate that lateral and medial displacement of the femur and increased fracture severity are strong predictors of compartment syndrome in tibial plateau fractures.

The researchers sought to determine the prognostic value of radiographic measurements with regard to compartment syndrome.“We believe that this information would be especially useful when evaluating patients who are obtunded, intubated, or otherwise unable to communicate,” said Stephen J. Becher, MD, presenter and coauthor of “Radiographic Predictors of Compartment Syndrome in Tibial Plateau Fractures.”

Collecting the data
Dr. Becher and his fellow researcher, Bruce Ziran, MD, performed a retrospective review of 240 patients with tibial plateau fractures who had been treated at a single institution between February 2006 and September 2010. They identified 159 patients (162 fractures) whose proximal femoral shaft and distal tibial shaft were intact and well visualized on anteroposterior (AP) radiographs. Most of the injuries (42 percent) were the result of motor vehicle collisions.

The cohort was divided into the following two groups:

  • tibial plateau fractures with compartment syndrome (n = 18; 13 males, 5 females; mean age = 42 years)
  • tibial plateau fractures without compartment syndrome (n= 141; 84 males, 57 females; mean age = 48 years)

Using the index AP radiographs, Drs. Ziran and Becher measured the tibial widening at the level of the joint, calculated as a ratio of the femoral width over tibial width (Fig.1); the medial to lateral displacement of the femur relative to the tibia, calculated as a ratio of the displacement over the femoral width (Fig. 2); and fracture severity in both groups. To account for differences in size and magnification, the intact width of the femoral condylar region served as a normalization parameter.

The researchers hypothesized that the risk of compartment syndrome would be increased when the femur was displaced medially relative to the tibia, stretching the vascular architecture. They also thought that certain radiographic measurements, including Schatzker grade, would be more pronounced on higher energy injuries that disrupted the soft tissues more than lower energy injuries. Schatzker is a grading system that classifies tibial plateau fractures into six types (Table 1).

Fig. 1 Tibial widening was calculated as a ratio of femoral width over tibial width.
Courtesy of Bruce Ziran, MD
Fig. 2 Femoral displacement was calculated as a ratio of the displacement over the femoral width.
Courtesy of Bruce Ziran, MD

Results
Multivariate analysis revealed that higher femoral displacement ratio (>10 percent, P = 0.004) and higher Schatzker fracture grade (IV–VI, P = 0.031) were strongly associated with compartment syndrome. Although the tibial widening ratio was significant in univariate analysis, it only trended in multivariate analysis, the authors noted.

“Contrary to our initial hypothesis, we found that displacement of the femur in both the lateral and medial directions, as well as increasing fracture severity, were strongly predictive of compartment syndrome,” said Dr. Ziran. “Now physicians have two additional methods to determine the amount of soft-tissue injury on the index AP radiograph. This can raise suspicion of an impending compartment syndrome if clinical evaluation is impossible.”

Dr. Becher added, “By knowing which fractures have the highest likelihood of developing compartment syndrome, orthopaedic surgeons can focus their diagnostic efforts where they are most needed.”

Dr. Ziran (Synthes, Tekartis, Stryker, Symbod) and Dr. Becher (no conflicts) are coauthors of “Radiographic Predictors of Compartment Syndrome in Tibial Plateau Fractures.”

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Bottom line

  • Diagnosing compartment syndrome typically depends on clinical assessment and compartment pressure measurements, but these may be difficult to perform in trauma patients who have undergone high energy injuries, have multisystem injuries, are intubated or sedated, or have altered mental status.
  • This retrospective review evaluated the prognostic value of radiographic measurements with respect to compartment syndrome in tibial plateau fractures.
  • Based on the results of this study, displacement of the femur in both the lateral and medial directions and a higher Schatzker grade are strongly predictive of compartment syndrome.

Additional Resources
Radiographic Predictors of Compartment Syndrome in Tibial Plateau Fractures