Pikulkaew Tanutum, Pornrattanamaneewong Chaturong, Chareancholvanich Keerati
Department of Orthopaedic Surgery, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
J Med Assoc Thai. 2012 Sep;95 Suppl 9:S1-5.
The present study was carried out to determine the relationship of true ankle center, the extreme-midpoint of the ankle and tibial axis for identification of lower limb alignment in Thai subjects.
There were 26 volunteers in our study, 13 male and 13 female with their ages ranged between 20 and 40 years. All underwent plain true antero-posterior radiograph of their both ankle joint including distal one-third of their tibias, which were controlled by a special splint. Three variables were made on the radiograph including one line and two points. The line was the axis of the distal tibia, which was performed by the use of connecting of center points of tibial diaphysis and metaphysis. The first point was the center of talar dome at the subchondral bone or the true ankle center and the second point, the anatomical ankle center or the extreme-midpoint of the ankle, which was the mid-point between the lateral most rim of lateral malleolus and the medial most rim of medial malleolus. Then the distances between the tibial axial line and these two points were measured by the use of perpendicular lines between the tibial axial line and those points.
The center of the talar dome was in the distal tibial axis in all radiographs. The anatomical ankle center or the extreme-midpoint of the ankle located lateral to the axis with an average distance of 2.1 +/- 1.1 mm. This finding did not depend on our volunteers' biodata.
To identify the lower endpoint of mechanical axis of the lower extremity in Thai subjects, the true ankle center located approximately 2 mm medial to the extreme-midpoint, which commonly used as anatomic landmark of the ankle center.
本研究旨在确定真踝关节中心、踝关节极中点与胫骨轴线之间的关系，以用于识别泰国受试者的下肢对线情况。
本研究有26名志愿者，13名男性和13名女性，年龄在20至40岁之间。所有人均接受了包括胫骨远端三分之一在内的双踝关节正位X线平片检查，检查过程由特殊夹板固定。在X线片上确定三个变量，包括一条线和两个点。这条线是胫骨远端轴线，通过连接胫骨干和干骺端的中心点来确定。第一个点是距骨穹窿软骨下骨的中心，即真踝关节中心；第二个点是解剖学踝关节中心或踝关节极中点，即外踝最外侧边缘与内踝最内侧边缘之间的中点。然后通过胫骨轴线与这些点之间的垂直线测量胫骨轴线与这两个点之间的距离。
在所有X线片中，距骨穹窿中心均位于胫骨远端轴线上。解剖学踝关节中心或踝关节极中点位于轴线外侧，平均距离为2.1±1.1毫米。这一发现与志愿者的生物数据无关。
为识别泰国受试者下肢机械轴的下端点，真踝关节中心位于极中点内侧约2毫米处，而极中点通常用作踝关节中心的解剖学标志。
