Prediction of outcome after ankle fracture.

STUDY DESIGN

Prospective inception cohort study of 62 consecutive patients seen in 2 orthopaedic clinics following ankle fracture.

OBJECTIVES

To investigate 4 putative predictors (age, fracture classification, acute management [surgical or nonsurgical], and ankle dorsiflexion range of motion measured at the time of cast removal) of outcome after ankle fracture and to develop simple predictive models of outcome after ankle fracture.

BACKGROUND

Ankle fracture is a common condition. However, few studies have investigated factors that predict outcome after ankle fracture.

METHODS AND MEASURES

Sixty-two consecutive subjects aged 17 or older with ankle fractures were recruited from 2 hospital orthopaedic clinics. Outcome measures recorded at 6 weeks and 6 months after cast removal included 2 functional questionnaires, patients' ratings of global improvement, and a measure of ankle dorsiflexion. The predictive value of 4 variables selected a priori was analyzed using bivariate and stepwise multiple linear regression.

RESULTS

Ankle dorsiflexion and fracture classification predicted outcome 6 weeks and 6 months after cast removal for all outcome measures used (P < .05, r2 = 0.09-0.47). Fracture management (surgical or nonsurgical) inconsistently predicted outcome at both 6 weeks and 6 months, and age did not predict outcome at either 6 weeks or 6 months after cast removal. The predictive models explain between 19% and 58% of the variance in outcomes 6 weeks after cast removal and 19% to 52% of the variance in outcomes 6 months after cast removal.

CONCLUSION

Ankle dorsiflexion measured at the time of cast removal and fracture classification are clinically significant predictors of outcome after ankle fracture; however, much unexplained variation in outcomes still exists.