University of Iowa, Iowa City, IA, USA.
UCHealth Medical Group, Loveland, CO, USA.
Foot Ankle Int. 2022 Aug;43(8):1099-1109. doi: 10.1177/10711007221091817. Epub 2022 May 24.
This work used software-guided radiographic measurement to assess the effects of progressive lateral column lengthening (LCL) on restoring alignment in a novel cadaveric model of stage II-B flatfoot deformity.
A stage II-B flatfoot was created in 8 cadaveric specimens by transecting the spring ligament complex, anterior deltoid, and interosseous talocalcaneal and cervical ligaments. Weightbearing computed tomographic (WBCT) scans were performed with specimens under 450 N of compressive load in the intact, flat, and 6-, 8-, and 10-mm lateral column-lengthening conditions. Custom software-guided radiographic measurements of the lateral talo-first metatarsal (Meary) angle, anteroposterior talo-first metatarsal angle, naviculocuneiform overlap, and 2 new measures (plantar fascia [PF] distance and angle) were recorded on digitally reconstructed radiographs. Four anonymized analysts performed measurements twice. Intra- and interobserver agreement was assessed using intraclass correlation coefficients (ICCs).
Six-millimeter LCL restored alignment closest to the intact foot in this new cadaveric model, whereas 10-mm lengthening tended toward overcorrection. The PF line displaced laterally in the flatfoot condition, and LCL restored the PF line to a location beneath the talonavicular joint. Interobserver agreement was excellent for PF distance (ICC = 0.99) and naviculocuboid overlap (ICC = 0.91), good for Meary angle (ICC = 0.81) and PF angle (ICC = 0.69), and acceptable for the talonavicular coverage angle (ICC = 0.65).
In this stage II-B cadaveric flatfoot model, cervical ligament transection was essential to create deformity after the medial hindfoot ligaments were transected. Software-guided radiographic measurement proved reliable; standardized implementation should improve comparability between studies of flatfoot deformity. The novel PF distance performed most consistently (ICC = 0.99) and warrants further study. With this model, we found that a 6-mm LCL restored alignment closest to the intact foot, whereas 10-mm lengthening tended toward overcorrection.
Future joint-sparing flatfoot corrections may consider using a relatively small LCL combined with other bony and/or anatomic ligament/tendon reconstructions.
本研究采用软件引导的放射测量来评估渐进性外侧柱延长（LCL）对新型 II-B 期扁平足畸形的尸体模型中对线恢复的影响。
通过切断弹簧韧带复合体、前三角肌、骨间跟距和颈韧带，在 8 个尸体标本中创建 II-B 期扁平足。在完整、扁平以及 6、8 和 10-mm 外侧柱延长条件下，对标本施加 450N 压缩负荷进行负重 CT（WBCT）扫描。在数字重建的射线照片上记录了软件引导的外侧距第一跖骨（Meary）角、前后距第一跖骨角、跗骨-楔骨重叠和 2 个新的测量值（足底筋膜[PF]距离和角度）的放射测量。由 4 名匿名分析员进行两次测量。使用组内相关系数（ICC）评估组内和组间的一致性。
在这种新型尸体模型中，6mm LCL 使对线最接近完整足，而 10mm 延长则倾向于过度矫正。PF 线在扁平足状态下向外侧移位，LCL 将 PF 线恢复到距跟舟关节下方的位置。PF 距离（ICC=0.99）和跗骨-楔骨重叠（ICC=0.91）的观察者间一致性极好，Meary 角（ICC=0.81）和 PF 角度（ICC=0.69）的观察者间一致性良好，距舟骨覆盖角（ICC=0.65）的观察者间一致性可接受。
在这个 II-B 期的尸体扁平足模型中，内侧后足韧带切断后，切断颈韧带是创建畸形所必需的。软件引导的放射测量证明是可靠的；标准化实施应提高扁平足畸形研究之间的可比性。新型 PF 距离表现最一致（ICC=0.99），值得进一步研究。通过该模型，我们发现 6mm LCL 使对线最接近完整足，而 10mm 延长则倾向于过度矫正。
未来的关节保留性扁平足矫正术可能需要考虑使用相对较小的 LCL 与其他骨和/或解剖韧带/肌腱重建相结合。
