Session VIII - Foot and Ankle

Bohler's Angle - Correlation with Long-Term Outcome in Displaced Intra-Articular Calcaneal Fractures

Richard E. Buckley, MD, FRCSC, Craig Loucks

University of Calgary, Calgary, Alberta, Canada

Purpose: To determine whether there is a correlation between Bohler's angle measured at three months and the two-year outcome as measured by SF-36 general health outcome and VAS disease specific outcome. To determine whether Bohler's angle has any prognostic value in terms of predicting outcome.

Method: Patients involved in this study are a cohort of a large ongoing multicentre randomized controlled clinical trial comparing operative and nonoperative treatment of displaced intra-articular calcaneal fractures (73-C(1-3)). All patients had displacement greater than 2 mm from anatomic position as demonstrated by axial and coronal CT's. The patients were treated after randomization into the operative or nonoperative treatment group and were followed with the same protocol of elevation, ice and analgesia. After six weeks, physiotherapy was continued with full-weightbearing allowed. Bohler's angle was measured by the two authors with the two values averaged allowing for four measurements: 1. initial Bohler's angle taken at the time of injury; 2. postoperative film for patients who underwent surgical reconstruction; 3. a two-week follow-up for all patients; 4. a final three-month follow-up Bohler's angle. Outcomes at two years were measured using the SF-36 and visual analog disease-specific clinical scoring scales. Both scores are validated and score out of 100 points.

Results: Eighty-eight patients had greater than two-year outcome scores representing 95 intra-articular calcaneal fractures. Forty-four patients were treated conservatively while 44 were treated operatively. The visual analog score at two years for the conservative treatment group (67.9) was not significantly different from the operative group (70.2). The average SF-36 score at two years for the conservative treatment group (65.7) was not significantly different from the operative group (71.0). There was no correlation between Bohler's angle at three months and two years with either the operative or conservative treatment group. Those patients in either treatment group with a Bohler's angle of 16° or greater had higher VAS scores (78.4) and two-year SF-36 score (73.2) versus those fractures with Bohler's angle less than 0, VAS (59.9) and SF-36 (56.6).

Discussion: The treatment of intra-articular calcaneal fractures remains controversial. Bohler's angle is a common measurement used, but, to this point, has not had strong significance attached to it. In this group of 88 displaced intra-articular calcaneal fractures, there is no difference in two-year outcome between the operative and nonoperative treatment groups using VAS or SF-36 scoring systems. There is no correlation between Bohler's angle at three months and clinical two-year outcome in this cohort of patients. Open reduction, internal fixation did successfully increase Bohler's angle, yet this did not alter outcome scoring.

Conclusion: Displaced intra-articular calcaneal fractures, regardless of treatment with a marked loss of Bohler's angle (less than 0°), had the worst outcomes. This indicated that increasing initial displacement, regardless of treatment, ends with a less good outcome.