French Mackenzie, Thorhauer Eric D, Kimura Tadashi, Sangeorzan Bruce J, Ledoux William R
School of Medicine, University of Washington, Seattle, WA, USA.
RR&D Center for Limb Loss and MoBility (CLiMB), VA Puget Sound, Seattle, WA, USA.
Foot Ankle Orthop. 2022 Sep 26;7(3):24730114221126457. doi: 10.1177/24730114221126457. eCollection 2022 Jul.
Quantifying normal sesamoid movement in relation to first metatarsophalangeal joint (MTPJ1) motion is essential to identifying aberrant kinematics and understanding how they may contribute to forefoot pain and dysfunction. The present study aims to report sesamoid displacement in relation to MTPJ1 extension and to compare sesamoid displacement with MTPJ1 range of motion (ROM) from several imaging modalities.
Using 10 fresh frozen cadaveric feet, sesamoid displacement was evaluated during simulated MTPJ1 extension. The ability of 3 MTPJ1 measurement techniques (goniometry, fluoroscopy, and unloaded cone beam computed tomography [CBCT]) in predicting sesamoid displacement were compared. Kinematics were expressed in a coordinate frame based on the specimen-specific first metatarsal anatomy, and descriptive statistics are reported.
In the sagittal plane in both neutral and maximally extended positions, the tibial sesamoid was located on average more anteriorly than the fibular sesamoid. The angular displacement of the tibial and fibular sesamoids in the sagittal plane were 30.2 ± 14.3 degrees and 35.8 ± 10.6 degrees, respectively. In the transverse plane, both sesamoids trended toward the body midline from neutral to maximum extension. The intersesamoidal distance remained constant throughout ROM. Of the 3 measurement techniques, MTPJ1 ROM from CBCT correlated best ( = 0.62 and 0.81 [ < .05] for the tibial and fibular sesamoid, respectively) with sagittal plane sesamoid ROM.
The sesamoids were displaced anteriorly and medially in relation to increasing MTPJ1 extension. CBCT was the most correlated clinical imaging technique in relating MTPJ1 extension with sesamoid displacement.
This study advances our understanding of the biomechanical function of the sesamoids, which is required for both MTPJ1 pathology interventions and implant design. These findings support the use of low-dose CBCT as the information gathered provides more accurate detail about bone position compared with other imaging methods.
量化籽骨相对于第一跖趾关节（MTPJ1）运动的正常运动对于识别异常运动学以及理解它们如何导致前足疼痛和功能障碍至关重要。本研究旨在报告籽骨相对于MTPJ1伸展的位移，并比较来自几种成像方式的籽骨位移与MTPJ1的运动范围（ROM）。
使用10只新鲜冷冻的尸体足，在模拟的MTPJ1伸展过程中评估籽骨位移。比较了3种MTPJ1测量技术（测角法、荧光透视法和无负荷锥形束计算机断层扫描[CBCT]）预测籽骨位移的能力。运动学以基于标本特异性第一跖骨解剖结构的坐标系表示，并报告描述性统计数据。
在矢状面的中立位和最大伸展位，胫骨籽骨平均比腓骨籽骨更靠前。胫骨和腓骨籽骨在矢状面的角位移分别为30.2±14.3度和35.8±10.6度。在横断面，从中立位到最大伸展位，两个籽骨都趋向身体中线。在整个ROM范围内，籽骨间距离保持恒定。在这3种测量技术中，CBCT测量的MTPJ1 ROM与矢状面籽骨ROM的相关性最佳（胫骨和腓骨籽骨的相关系数分别为0.62和0.81[P<0.05]）。
随着MTPJ1伸展增加，籽骨向前和向内侧移位。CBCT是将MTPJ1伸展与籽骨位移相关联的最具相关性的临床成像技术。
本研究增进了我们对籽骨生物力学功能的理解，这对于MTPJ1病理学干预和植入物设计都是必需的。这些发现支持使用低剂量CBCT，因为与其他成像方法相比，所收集的信息能提供关于骨位置更准确的细节。
