Department of Radiology, UC San Diego Health, 200 W. Arbor Drive, #8226, San Diego, CA, 92103, USA.
Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital,, Mahidol University, Bangkok, Thailand.
Skeletal Radiol. 2022 Jan;51(1):191-200. doi: 10.1007/s00256-021-03800-0. Epub 2021 Jun 23.
Tarsal coalition is known to cause abnormal talocrural stress, hindfoot malalignment, and ankle sprains. These can all be associated with osteochondritis dissecans (OCD) of the talar dome. We present the first detailed description of a series of talar OCDs occurring in patients with tarsal coalition, with the goal of determining whether there is an increased prevalence of OCDs among patients with tarsal coalition.
We studied ankle MRIs in 57 patients with tarsal coalitions, excluding those with a reported inciting traumatic event. The MRIs were performed on magnetic field strengths ranging from 0.3 to 1.5 T and included axial, coronal, and sagittal T1 and T2 or PD fat-suppressed sequences. We evaluated the morphology and location of classically described OCDs in these patients, type and location of concomitant tarsal coalition, and, when available, the presence of pes planus and hindfoot valgus on weight-bearing radiographs. Chi-squared analysis was used to compare categorical variables and a Student's t test was used for parametric continuous variables. Additionally, logistic regression was used to compute the odds ratio of talar OCD associated with patient age, gender, laterality, pes planus status, hindfoot valgus status, and coalition type.
Eighty-nine percent of tarsal coalitions were non-osseous coalitions and the calcaneonavicular space was the most common site of abnormal tarsal connection (54.4%). In the 29 patients with tarsal coalitions and talar OCDs, OCDs commonly occurred medially (75.9%). In the sagittal plane, talar OCDs occurred centrally, with only one case sparing the central talar dome. The mean surface area of the 29 OCDs was 89.7 mm. Both osseous coalition and hindfoot valgus were associated with smaller talar OCD mean surface area (p = 0.015 and p = 0.0001, respectively). There was no association between depth and surface area of talar OCD with either coalition location or presence of pes planus (coalition location: p = 0.455 for depth and p = 0.295 for surface area; presence of pes planus: p = 0.593 for depth and p = 0.367 for surface area).
Talar OCD prevalence is higher in patients with tarsal coalition than that reported for the general population. This occurrence may relate to altered biomechanics and repetitive talocrural stress owing to altered subtalar motion, particularly given the findings of increased odds of talar OCD in older patients, as well as weak associations between OCD surface area and both non-osseous coalition and hindfoot alignment. However, we did not find any specific OCD morphologic features attributable to the precise location of the tarsal coalition.
跗骨联合已知会导致距下关节异常应力、后足对线不良和踝关节扭伤。这些都可能与距骨顶部的剥脱性骨软骨炎（OCD）有关。我们首次详细描述了一组发生在跗骨联合患者中的距骨 OCD，目的是确定跗骨联合患者中 OCD 的患病率是否增加。
我们研究了 57 例跗骨联合患者的踝关节 MRI，排除了有报道的诱发创伤性事件的患者。MRI 在磁场强度为 0.3 至 1.5 T 的范围内进行，包括轴向、冠状和矢状 T1 和 T2 或 PD 脂肪抑制序列。我们评估了这些患者中经典描述的 OCD 的形态和位置、联合类型和位置，以及负重位 X 线片上是否存在平足和后足外翻。卡方分析用于比较分类变量，学生 t 检验用于参数连续变量。此外，逻辑回归用于计算与患者年龄、性别、侧别、平足状态、后足外翻状态和联合类型相关的距骨 OCD 的优势比。
89%的跗骨联合是非骨性联合，跟距骨间最常见的异常跗骨连接部位（54.4%）。在 29 例有跗骨联合和距骨 OCD 的患者中，OCD 常见于内侧（75.9%）。在矢状面，距骨 OCD 发生在中央，仅有 1 例中央距骨穹顶幸免。29 例 OCD 的平均表面积为 89.7 mm。骨性联合和后足外翻均与较小的距骨 OCD 平均表面积相关（p=0.015 和 p=0.0001）。距骨 OCD 的深度和表面积与联合位置或平足的存在均无相关性（联合位置：深度 p=0.455，表面积 p=0.295；平足的存在：深度 p=0.593，表面积 p=0.367）。
跗骨联合患者中距骨 OCD 的患病率高于一般人群。这种发生可能与由于距下关节运动改变导致的生物力学改变和反复距下关节应力有关，特别是考虑到在年龄较大的患者中，距骨 OCD 的发生几率增加，以及 OCD 表面积与非骨性联合和后足对线之间的弱相关性。然而，我们没有发现任何特定的 OCD 形态特征归因于跗骨联合的精确位置。
