Preoperative imaging and intraoperative stress test for Weber type B ankle fracture without medial malleolus fracture / 中华创伤骨科杂志

ABSTRACT

Objective:To explore the characteristics and clinical values of preoperative imaging signs and intraoperative stress test in the surgery of the Weber type B fracture without medial malleolar fracture.Methods:The data of 52 patients were reviewed who had been treated at Orthopaedic Trauma Department, Beijing Jishuitan Hospital for Weber type B ankle fracture without medial malleolar fracture from January 2018 to December 2021.They were assigned into 2 groups depending on their results of intraoperative stress test. In the positive group of 21 cases showing a positive intraoperative stress test, there were 19 males and 2 females with an age of (34.4±10.2) years; in the negative group of 31 cases showing a negative intra operative stress test, there were 22 males and 9 females with an age of (39.5±14.8) years. The 2 groups were compared in terms of the medial clear space, tibiofibular clear space and vertical length of the fibular fracture on the preoperative X-ray film, as well as the relative size of the posterior malleolar fracture fragment on the preoperative CT. The imaging characteristics of intraoperative stress tests were also observed.Results:There was no significant difference between the 2 groups in the preoperative general data, showing comparability between groups ( P>0.05). The medial clear space (7.2±2.5) mm and the vertical length of the fibular fracture [49.2 (33.7, 58.7) mm] in the positive group were significantly larger than those in the negative group [(4.5±1.7) mm and 29.6 (24.7, 36.0) mm] ( P<0.05). There was no significant difference between the 2 groups in the lower tibiofibular space [(6.0±1.9) mm versus (5.2 ± 1.4) mm] or in the relative size of posterior malleolar fracture measured by CT [15.8% (6.9%, 19.1%) versus 12.7% (0%, 18.9%)] ( P>0.05). The intraoperative stress test imaging data of a total of 22 cases were collected from the 2 groups (11 cases from each of the 2 groups). During the stress test, only the medial clear space was widened with no widening of the inferior tibiofibular space was found in 7 cases (5 cases in the positive group and 2 cases in the negative group). Conclusions:A routine stress test is recommended for Weber B ankle fracture without medial malleolus fracture, because instability sometimes exists after fibular fixation. Patients with a wider medial clear space and a longer fibular fracture line on X-ray after injury are more likely to be afflicted by instability after fibular fixation. In the patients with a widened medial clear space but without a widened inferior tibiofibular clear space during an intraoperative stress test, it calls for further study whether it is necessary to fix the inferior tibiofibular joint.