Lawlor Mark C, Kluczynski Melissa A, Marzo John M
1 The Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Amherst, NY, USA.
Foot Ankle Int. 2018 Jul;39(7):850-857. doi: 10.1177/1071100718761035. Epub 2018 Mar 13.
The utility of computed tomography (CT) for measuring medial clear space (MCS) for determination of the stability of supination external rotation (SER) ankle fractures and in comparison to standard radiographs is unknown. We compared MCS on gravity stress (GS) radiographs to GS and weight bearing (WB) cone-beam CT (CBCT).
An AO SER 44B3.1 ankle fracture was simulated in 10 human cadavers, also serving as controls. MCS was measured on GS radiographs, GS CBCT, and a simulated WB CBCT scan. Specimens were stable if MCS was <5 mm and unstable if MCS was ≥5 mm. Paired t tests were used to compare MCS from each imaging modality for controls versus SER injuries and stable versus unstable specimens.
Compared with controls assessed by GS radiographs, MCS was greater for an SER injury when assessed by GS radiograph and GS CBCT scan within the stable group. Compared with controls assessed by GS radiographs, MCS was greater for SER injuries when assessed by GS radiograph, GS CBCT scan, and WB CBCT within the unstable group. MCS was reduced for stable versus unstable SER injuries assessed by WB CBCT.
In a cadaveric model of SER ankle fracture, the medial clear space was statistically significantly greater for the experimental condition when assessed by gravity stress radiograph and gravity stress CBCT scan. Under weight-bearing conditions, the cone-beam CT scanner distinguished between stable and unstable ankles in the experimental condition.
This study suggests that a WB cone-beam CT scan may be able to distinguish between stable and unstable SER ankle fractures and influence operative decision making.
计算机断层扫描（CT）用于测量内侧间隙（MCS）以确定旋后外旋（SER）型踝关节骨折稳定性的效用，以及与标准X线片相比的情况尚不清楚。我们将重力应力（GS）X线片上的MCS与GS和负重（WB）锥形束CT（CBCT）进行了比较。
在10具人体尸体上模拟AO SER 44B3.1型踝关节骨折，这些尸体也作为对照。在GS X线片、GS CBCT和模拟WB CBCT扫描上测量MCS。若MCS<5mm，则标本为稳定；若MCS≥5mm，则标本为不稳定。采用配对t检验比较每种成像方式下对照与SER损伤以及稳定与不稳定标本的MCS。
与通过GS X线片评估的对照相比，在稳定组中，通过GS X线片和GS CBCT扫描评估时，SER损伤的MCS更大。与通过GS X线片评估的对照相比，在不稳定组中，通过GS X线片、GS CBCT扫描和WB CBCT评估时，SER损伤的MCS更大。通过WB CBCT评估，稳定与不稳定的SER损伤的MCS有所降低。
在SER型踝关节骨折的尸体模型中，通过重力应力X线片和重力应力CBCT扫描评估时，实验条件下的内侧间隙在统计学上显著更大。在负重条件下，锥形束CT扫描仪在实验条件下能够区分稳定和不稳定的踝关节。
本研究表明，负重锥形束CT扫描可能能够区分稳定和不稳定的SER型踝关节骨折，并影响手术决策。
