内踝间隙随踝关节背伸与跖屈角度而变化的测量

Radiographic measurement of medial clear space with ankle dorsiflexion and plantar flexion angle change

目的探讨内踝间隙(media clear space,MCS)随踝关节背伸与跖屈的变化及其临床意义。方法测量13例正常健康志愿者在踝关节中立位、背伸15°位、跖屈30°位的MCS及踝上间隙(superior clear space,SCS)数值,分析各组数据,并对其差异行统计学检验。结果踝关节中立位平均MCS(3.48±0.36)mm,MCS随踝关节跖屈加大而增宽。自中立位至背伸15°位,MCS平均减少0.24mm,自中立位至跖屈30°位,MCS平均增加0.39mm。MCS随踝关节跖屈而增宽存在较大的个体差异。在13例志愿者中,7例(53.8%)内踝间隙与踝上间隙的差值(media clear space-superior clear space,MCS-SCS)增加超过0.5mm,3例超过0.6mm,1例超过0.8mm。结论本文的测量证实了MCS随踝关节跖屈加大而增宽的现象,此种增宽可称之为MCS的生理性增宽。大部分MCS的生理性增宽幅度较小,部分人群存在较大幅度的增宽,可干扰对于踝关节骨折时MCS病理性增宽的判断,影响临床决策。因此,对于需要准确观察MCS是否增宽的病例,拍片时应确保踝关节处于中立位。

Objective To investigate the medial clear space with ankle dorsiflexion and plantar flexion change and its clinical significance. MethodAP mortise radiographs were made for thirteen healthy volunteers , with the ankle in positions of neutral, dorsiflexion 15 degrees position and plantar flexion 30 degrees position. Medial clear space （MCS） and superior clear space（SCS） were measuerd on each radiograph. The difference of the data were statistically analysied.ResultThe average MCS of ankle in the neutral position was（3.48±0.36） mm, and it was widened with ankle plantar flexion increased. MCS was reduced by an average of 0.24mm when the ankle be positioned from the neutral position to the dorsiflexion 15 degrees position, and increased by an average of 0.39mm from the neutral position to plantar flexion 30 degrees position. The width of MCS with ankle plantar flexion were changed individual, in 13 volunteers, 7 cases （53.8%） MCS-SCS increased more than 0.5mm, 3 cases of more than 0.6 mm, and 1 case more than 0.8mm.ConclusionThe measurements confirmed the rule that the MCS wide with ankle plantar flexion increasing. This increase width can be referred as physiologically widenedof MCS widened. Most of the physiological widened of MCS is in a lesser extent, but part of the population has a greater extent, which can interfere with the judgement of pathological increased MCS when the ankles fractures, and affect the clinical decision making.Therefore, for the cases that need accurate observation on whether the MCS is widened, the ankle joint should be in a neutral position when radiographed.