Session II - Foot and Ankle

Factors Affecting Outcome in Tibial Plafond Fractures

Todd M. Williams, MD; J.Lawrence Marsh, MD; James V. Nepola, MD, University of Iowa Hospitals and Clinics, Iowa City, IA; Thomas A. DeCoster, MD, University of New Mexico, Albuquerque, NM; Shepard R. Hurwitz, MD, University of Virginia, Charlottesville, VA; Douglas R. Dirschl, MD, University of North Carolina, Chapel Hill, NC

Purpose: To identify the major determinants of outcome in a group of high- energy tibial plafond fractures. Knowledge of the factors that determine outcome is crucial to clarify treatment goals and counsel patients.

Methods: The outcome of thirty-two tibial plafond fractures treated with a uniform technique of cross-ankle external fixation and limited approaches for reduction and fixation of the articular surface was measured in four different ways. A clinical ankle score, a radiographic arthrosis score, the SF-36 and the patient's ability to return to their previous level of employment were used. Patients were followed for a minimum of two years (avg. 46.5 months, range 24-129). Fractures with major complications (deep infections, nonunions, and angular malunions) uniformly result in poor outcomes and were therefore excluded. Statistical analysis was used to determine what fracture-specific and patient-specific variables had the most significant effect on the outcome measures. The fracture-specific variables that were evaluated included: severity of injury and accuracy of articular reduction (measured with a rank order method), open versus closed injury, and presence or absence of fracture blisters. The patient specific variables included: age, gender, level of education, income level, presence of associated injuries, type of employment and whether or not the injury occurred as the result of a work related accident.

Results: The four outcome measures did not correlate with each other (p = 0.20 -p = 0.56). Both severity of injury as measured on preoperative radiographs (p = 0.0001) and accuracy of articular reduction, measured on postoperative films (p = 0.0001) correlated strongly with arthrosis. The ankle score (a subjective, self administered 100 point score) correlated with level of education (p = 0.02), female sex (p = 0.02), and non-work related injuries (p = 0.05). The ankle score did not correlate with either severity of injury (p = 0.25) or accuracy of reduction (p = 0.71). There was a statistically significant relationship between level of education and the ability to return to work (p = 0.02).

Discussion: We were surprised that the four outcomes we evaluated did not correlate with each other. Different patient- or fracture-specific variables correlated with each of the different outcome measures. Radiographic outcome was best predicted by radiographs since both severity of injury and accuracy of reduction as assessed on pre- and postoperative x-rays respectively, strongly correlated with the arthrosis measured on radiographs at follow-up. Unfortunately, the injury or reduction radiographs did not show any significant relationship to outcome as measured by the clinical ankle score, the SF-36, or the patient's ability to return to work. The patient-derived outcome measures were more influenced by patient specific socioeconomic factors. Pain and function assessed through the ankle score resulted in higher scores in women and patients with college degrees or higher and lower scores in patients with a work-related injury. The ability to return to work was affected primarily by the level of education of the injured patient.

Conclusion: This study highlights the difficulties in predicting medium and long-term patient outcome following these severe articular fractures using the measures currently available.