The Hospital for Special Surgery, Department of Foot and Ankle Surgery, 535 East 70th Street, New York, NY 10021, USA.
Foot Ankle Int. 2009 Dec;30(12):1168-76. doi: 10.3113/FAI.2009.1168.
Stage II flatfoot secondary to posterior tibial tendon insufficiency may be subclassified into mild (IIa) and severe (IIb) deformity based on the degree of talonavicular abduction. Current assessment of this abduction is difficult. We hypothesized that two new anteroposterior radiographic parameters, the lateral talonavicular incongruency angle (IA) and incongruency distance (ID) would demonstrate good reliability, correlate with current abduction parameters, and differ in IIb deformity, IIa deformity, and controls.
Preoperative radiographs for consecutive patients undergoing flatfoot reconstruction were reviewed and subdivided into those with a Stage IIb (n = 32) or Stage IIa (n = 8) deformity. A third group of patients without flatfoot served as control (n = 30). Radiographs were measured blindly by two investigators. Reliability was assessed with intraclass correlation coefficients (ICC), correlation with existing parameters with Pearson coefficients, and comparison between groups with analysis of variance.
The mean intrarater and interrater ICC's for the IA (0.88 and 0.81, respectively) were high. The IA correlated well with the coverage angle (r = 0.86) and uncoverage percent (r = 0.76). The IA was higher in the IIb versus IIa patients (p = 0.007) and in the IIb group versus control (p < 0.001). The ID demonstrated excellent reliability (ICC's of 0.83 and 0.83), but correlated poorly with the two other abduction parameters (r = -0.59 and -0.49) and failed to differentiate between the three groups (p = 0.0528).
This data suggests that the IA is reliable and may help subclassify Stage II flatfoot deformity.
由于胫骨后肌腱功能不全导致的 II 期扁平足可能根据距舟骨外展的程度进一步分为轻度（IIa）和重度（IIb）畸形。目前对这种外展的评估较为困难。我们假设两个新的前后位 X 线参数，即外侧距舟关节不吻合角（IA）和不吻合距离（ID）具有良好的可靠性，与目前的外展参数相关，且在 IIb 畸形、IIa 畸形和对照组之间存在差异。
回顾性分析连续接受扁平足重建的患者的术前 X 线片，并将其分为 IIb 期（n = 32）或 IIa 期（n = 8）畸形。第三组无扁平足的患者作为对照组（n = 30）。X 线片由两名研究者进行盲法测量。采用组内相关系数（ICC）评估可靠性，采用 Pearson 系数评估与现有参数的相关性，采用方差分析比较组间差异。
IA 的组内和组间的平均 ICC 分别为 0.88 和 0.81，均较高。IA 与覆盖角（r = 0.86）和未覆盖百分比（r = 0.76）相关性良好。IIb 期患者的 IA 高于 IIa 期患者（p = 0.007），IIb 期患者的 IA 高于对照组（p < 0.001）。ID 具有极好的可靠性（ICC 为 0.83 和 0.83），但与另外两个外展参数相关性差（r = -0.59 和 -0.49），且无法在三组间进行区分（p = 0.0528）。
本研究数据表明，IA 是可靠的，可能有助于对 II 期扁平足畸形进行分类。
