Department of Orthopedic Surgery, Nara Medical University, 840 Shijo, Kashihara, Nara, 634-8522, Japan.
Department of Orthopedics, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, 90110, Thailand.
BMC Musculoskelet Disord. 2021 Aug 28;22(1):737. doi: 10.1186/s12891-021-04618-6.
Varus ankle osteoarthritis is classified using only weightbearing anteroposterior ankle radiographs; however, sagittal ankle alignment may also affect the position and extent of joint space obliteration. We hypothesized that the sagittal alignment of the ankle may also affect the position and extent of joint space obliteration visible on the coronal section; therefore, we identified the sites of joint space obliteration in patients with stage 3 varus ankle osteoarthritis for comparison with the sites observed on simulated weightbearing computed tomography and investigated the effects of anterior and posterior ankle subluxation.
Simulated weightbearing computed tomography scans of 83 ft with varus ankle osteoarthritis (26 stage 3a, 57 stage 3b) were performed to check for joint space obliteration in the ankle. Further classification as exhibiting either anterior, posterior, or no subluxation on weightbearing lateral radiographs was performed.
Anterior, posterior, and no subluxation was seen in 5, 9, and 12 ankles among the 26 classified as stage 3a, respectively, and in 22, 12, and 23 ankles among the 57 classified as stage 3b, respectively. The mean tibial lateral surface angle on weightbearing lateral radiographs in stage 3a ankles was 75.6, 83.3, and 80.3 degrees in the anterior, posterior, and no subluxation groups, respectively; and 75.5, 86.6, and 82.7 degrees in stage 3b ankles (p < .05). In stage 3b ankles, widespread joint space obliteration was observed at the anterior distal articular surface of the tibia in all 22 ankles with anterior subluxation and at the posterior distal articular surface of the tibia in all 12 ankles with posterior subluxation.
Simulated weightbearing computed tomography revealed joint space obliteration at the anterior distal articular surface of the tibia in stage 3b ankles with anterior subluxation and at the posterior side in stage 3a and 3b ankles with posterior subluxation. In some patients with stage 3 varus ankle osteoarthritis, the obliteration of the joint space is difficult to evaluate accurately using only weightbearing anteroposterior radiographs; weightbearing lateral radiographs should also be performed.
内翻踝骨关节炎仅通过负重前后位踝关节 X 线片进行分类；然而，踝关节矢状面排列也可能影响关节间隙消失的位置和程度。我们假设踝关节矢状面排列也可能影响冠状位上可见的关节间隙消失的位置和程度；因此，我们确定了 3 期内翻踝骨关节炎患者的关节间隙消失部位，并与模拟负重 CT 进行比较，并研究了前、后踝半脱位的影响。
对 83 例内翻踝骨关节炎（26 例 3a 期，57 例 3b 期）患者进行模拟负重 CT 扫描，以检查踝关节的关节间隙消失情况。进一步根据负重侧位 X 线片是否存在前、后或无半脱位进行分类。
26 例 3a 期患者中，分别有 5、9 和 12 例踝关节出现前、后或无半脱位，57 例 3b 期患者中，分别有 22、12 和 23 例踝关节出现前、后或无半脱位。负重侧位 X 线片上 3a 期踝关节胫骨外侧表面角分别为前、后、无半脱位组的 75.6、83.3 和 80.3 度，3b 期踝关节为 75.5、86.6 和 82.7 度（p<0.05）。在 3b 期踝关节中，所有 22 例前脱位踝关节和所有 12 例后脱位踝关节均在前胫骨远端关节面广泛出现关节间隙消失。
模拟负重 CT 显示，3b 期前脱位踝关节的胫骨前远端关节面和 3a、3b 期后脱位踝关节的胫骨后侧出现关节间隙消失。在一些 3 期内翻踝骨关节炎患者中，仅通过负重前后位 X 线片很难准确评估关节间隙的消失；还应进行负重侧位 X 线片检查。
