Are radiological measurements reliable methods in the postoperative follow-up of calcaneal fractures?

Abstract

Background: Böhler s angle (BA) and the crucial angle of Gissane (CAG) are the most frequently used objective measurements for the follow-up of fixation following calcaneus fracture surgery. However, the measurements of these angles by different people can affect the results and cause conflicting interpretations of different results obtained. This has caused confusion in the literature. Aims: The aim of this study was to investigate the reliability and disagreement of BA and the CAG, and to interrogate the veracity of angular changes in the postoperative period of calcaneal fractures. Methods: In the first round, a total of 82 postoperative lateral radiographs were investigated to assess the inter-tester reliability and disagreement. Second round; all radiographs were re-evaluated by two testers 15 days after the first measurement. These values were used to assess the intra and inter-tester reliability, disagreement and false negative/positive angular change. All measurements were performed separately by a radiologist and an orthopedic surgeon. Results: Inter- and intra-tester reliability was found low to high in BA (ICC: 0.465 to 0.837), and moderate to very high in CAG (ICC: 0.661 to 0.926). The mean inter-tester disagreement of BA was 4.19° and 6.07°. These values were 4.76° and 7.22° for CAG. The mean intra-tester disagreement of BA was 4.09° for the orthopedic surgeon and 3.97° for the radiologist. These values were 4.96° and 4.39° for CAG respectively. The false negative angular difference was found for BA in 51 (62.2%) cases for the orthopedic surgeon and 46 (56.1%) cases for the radiologist. The mean values were -3.87° and -4.21°, respectively. For the CAG, the false positive angular difference was found in 43 (52.4%) cases for both the orthopedic surgeon and the radiologist. The mean values were +5.01° and +4.72°, respectively. Conclusion: These angles alone should not be considered to be of guidance in the postoperative period. If any angular change is determined on the lateral radiographs, this could arise from a disagreement or false angular change.