Does axial view still play an important role in dealing with calcaneal fractures?

BACKGROUND The study aimed to analyze the role of axial view in different phases of treatment and demonstrate whether axial view is still useful in evaluating the calcaneal fractures. METHODS 156 patients with suspected unilateral calcaneal fractures were enrolled in the study, axial and lateral view of the affected foot and single axial view of the unaffected foot were gained. 16 were excluded due to unsatisfying axial radiograph. The remain 140 patients were eventually included into the study. Two separate assessments were conducted on two occasions with a three weeks interval to diagnose fractures. Lateral views were assessed firstly, and lateral combined with axial views were assessed three weeks later. Each of the 140 sets was evaluated by one of 6 surgeons randomly. Sensitivity and specificity value were compared between the two assessments. A new value Z which can directly reflect the degree of bulge on the calcaneal lateral wall on the axial view were introduced into the study. Z value of the 140 unaffected feet were measured. Data of another group of 31 patients who confirmed their lateral hindfoot pain caused by widening of calcaneus was reviewed. Liner regression was employed to analyze the relationship between angle Z and the severity of lateral pain. RESULTS According to the two assessments, without axial view, specificity value will be significantly lower in diagnosing calcaneal fractures (p = 0.024) and sensitivity value will be significantly lower in distinguishing intra-articular fractures (p < 0.001). The normal threshold of angle Z was estimated from 98.06° to 100.64° (p <0.001). Liner regression shows that the lateral hindfoot pain will obviously aggravate along with the increasing of angle Z value (p <0.001). CONCLUSIONS Axial view is useful in diagnosing a patient with suspected calcaneal fracture especially for distinguishing intra-articular fractures and selection for CT scan. With the introduction of angle Z, axial view can get excellent performance in intra-operative assessment as well as in post-operative follow up procedure. Axial view can still play an irreplaceable role in assessing and evaluating calcaneal fractures, and can be employed as an essential reference during surgical procedure .