Increased morphine requirements are predictive of acute compartment syndrome in adults with tibia fractures.

Purpose: The purpose of this study was to determine if increased milligram morphine equivalent (MME) requirements are a predictor of adult compartment syndrome in patients with tibia fractures.

Methods: A retrospective case-control study at a level-1 trauma center was performed over a five year period. Patients with tibia fractures who had acute compartment syndrome (ACS) requiring fasciotomy (n = 26) were matched with controls (n = 25). MME and pain scores were assessed within the 24 hour period preceding fasciotomy (cases) or fixation (controls). The presence or absence of the "6 Ps" and other clinical signs (diastolic blood pressure [DBP]) were also analyzed.

Results: Mean MMEs two hours before surgery was 25.5 ± 39.2 for ACS patients versus 8.6 ± 11.1 in controls (P = 0.043), while the mean pain scores were 8.8 ± 1.8 and 7.0 ± 2.5 (P = 0.049), respectively. Multivariable regression showed patients with ACS consumed 16.9 MME more than controls within two hours of surgery (P = 0.043) and scored 1.8 points higher on the numeric pain rating scale (P = 0.049). The mean number of clinical signs of compartment syndrome in the ACS patients was 3.4 ± 1.3 compared to 0.84 ± 0.85 in controls (P < 0.001). DBP was significantly higher in ACS patients within two to four hours of surgery (P = 0.005).

Conclusion: Increased MME requirements and pain scores within two hours of surgery were significant predictors of ACS following tibia fracture. Increased narcotic requirements, pain scores, and DBP may be useful objective indicators of evolving ACS, in addition to the traditional signs, and should be closely monitored in the at-risk patient.