Foot & Ankle Research and Innovation Laboratory, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA.
Department of Orthopaedic Surgery, Foot & Ankle Service, Massachusetts General Hospital, Boston, MA, USA.
Foot Ankle Int. 2020 Jul;41(7):859-865. doi: 10.1177/1071100720917682. Epub 2020 May 17.
Weight-bearing computed tomography (WBCT) allows evaluation of the distal syndesmosis under physiologic load. We hypothesized that WBCT volumetric measurement of the distal syndesmosis would be increased on the injured as compared to the contralateral uninjured side and that these 3-dimensional (3D) calculations would be a more sensitive determinant than 2-dimensional (2D) methodology among patients with syndesmotic instability.
Twelve patients with unilateral syndesmotic instability requiring operative fixation who underwent preoperative bilateral foot and ankle WBCT were included in the study group. The control group consisted of 24 patients without ankle injury who underwent similar imaging. On WBCT scan, 2D measurements of the syndesmosis joint were first measured 1 cm above the joint line in the axial plane via syndesmotic area and distances between the anterior, middle, and posterior quadrants. Thereafter, comparative 3D volumetric measurements of the syndesmotic joint were also calculated: (1) from the tibial plafond extending until 3 cm proximally, (2) 5 cm proximally, and (3) 10 cm proximally.
In patients with unilateral syndesmotic instability, all 3 weight-bearing volumetric measurements were significantly larger on the injured side as compared to the contralateral, uninjured side ( < .001). In the control group, there was no difference between syndesmotic volumes at any level. Of these 3 anatomic reference points, the 3D measurement spanning from the tibial plafond to a level 5 cm proximally had the highest relative volumetric ratio between the injured and uninjured side, suggesting it is the most sensitive in distinguishing between stable and unstable syndesmotic injury ( < .001). Notably, this 3D volumetric measurement was also more sensitive than 2D measurements ( = .001).
3D volumetric measurement of the syndesmosis joint appears to be the most effective way to diagnose syndesmotic instability, compared with more traditional 2D syndesmosis measurement.
Level III, retrospective comparative study.
负重位计算机断层扫描（WBCT）可在生理负荷下评估下胫腓联合的远端。我们假设，与对侧未受伤侧相比，WBCT 对下胫腓联合的容积测量值在受伤侧会增加，并且这些 3 维（3D）计算在有下胫腓联合不稳定的患者中比 2 维（2D）方法更敏感。
研究组纳入了 12 例需要手术固定的单侧下胫腓联合不稳定患者，这些患者术前均行双侧足部和踝关节 WBCT。对照组由 24 例无踝关节损伤的患者组成，他们也接受了类似的影像学检查。在 WBCT 扫描中，首先在矢状面距关节线 1cm 处测量下胫腓联合关节的 2D 测量值，测量方法为测量联合区域和前、中、后象限之间的距离。此后，还计算了下胫腓联合的比较性 3D 容积测量值：（1）从距骨平台延伸至近端 3cm，（2）近端 5cm，和（3）近端 10cm。
在单侧下胫腓联合不稳定的患者中，与对侧未受伤侧相比，所有 3 种负重位容积测量值在受伤侧均明显更大（<0.001）。在对照组中，在任何水平下，下胫腓联合容积均无差异。在这 3 个解剖参考点中，从距骨平台延伸至近端 5cm 水平的 3D 测量值，其受伤侧与未受伤侧的相对容积比最高，提示其在区分稳定和不稳定的下胫腓联合损伤方面最敏感（<0.001）。值得注意的是，这种 3D 容积测量值也比 2D 测量值更敏感（=0.001）。
与更传统的 2D 下胫腓联合测量相比，下胫腓联合关节的 3D 容积测量似乎是诊断下胫腓联合不稳定的最有效方法。
III 级，回顾性对比研究。
