*University of Western Australia, School of Allied Health, Podiatric Medicine and Surgery Discipline, Crawley, Western Australia, Australia.
†Advanced Foot Surgery Centre, Perth, Western Australia, Australia.
J Am Podiatr Med Assoc. 2024 Jan-Feb;114(1). doi: 10.7547/21-129.
A rounded lateral first metatarsal head shape is associated with higher rates of hallux abducto valgus recurrence following corrective surgery; however, the effect of the lateral first metatarsal head shape on the hallux abduction angle (HAA) has not yet been explored in a nonpathologic, pre-pointe ballet dancer population. The primary purpose of this study was to investigate the effect of the lateral first metatarsal head shape on the HAA when pre-pointe female dancers force their turnout.
Seventeen female, pre-pointe ballet students (mean age, 10.8 ± 0.95 years) participated in this study. Fluoroscopic images of each dancer's dominant foot were taken, and the lateral first metatarsal head shape was classified visually. Each dancer performed three consecutive stances of natural double-leg upright posture: both functional and forced turnout. HAAs were obtained by marking medial bony landmarks on paper and were compared to photographic measurements.
No significant difference was found between the round and angular lateral first metatarsal head shape for the change in HAA from natural double-leg upright posture to forced turnout. Hallux abduction angle significantly increased by 4.6° (P < .001) in forced turnout compared to the natural double-leg upright posture for the photographic method, whereas the paper method demonstrated an increase of 2.6° (P = .007). No statistical differences were found between the paper and photographic methods in measuring the HAA for all stances.
Our findings suggest no association between the HAA and lateral first metatarsal head shape; however, HAA does increase when a dancer assumes forced turnout. The paper method demonstrated similar reliability to the photographic method and shows the potential for future use as a clinical tool in assessing hallux abducto valgus.
圆形的外侧第一跖骨头形状与拇外翻矫正手术后的复发率较高有关；然而，外侧第一跖骨头形状对拇趾外展角（HAA）的影响尚未在非病理性、前足尖芭蕾舞舞者人群中得到探索。本研究的主要目的是在芭蕾舞前足尖女性舞者强迫外展时，研究外侧第一跖骨头形状对 HAA 的影响。
17 名女性前足尖芭蕾舞学生（平均年龄，10.8±0.95 岁）参与了这项研究。对每位舞者的优势脚进行荧光透视图像拍摄，并通过肉眼观察对外侧第一跖骨头形状进行分类。每位舞者连续完成三种自然双腿直立姿势：自然姿势和强迫外展姿势。通过在纸上标记内侧骨性标志点来获得 HAA，并与照相测量值进行比较。
在从自然双腿直立姿势到强迫外展姿势的 HAA 变化方面，圆形和角形外侧第一跖骨头形状之间没有显著差异。与自然双腿直立姿势相比，强迫外展时 HAA 显著增加 4.6°（P<0.001），而照相法显示增加 2.6°（P=0.007）。在所有姿势中，HAA 的测量值在纸法和照相法之间没有统计学差异。
我们的研究结果表明 HAA 与外侧第一跖骨头形状之间没有关联；然而，当舞者采用强迫外展时，HAA 确实会增加。纸法与照相法具有相似的可靠性，显示出作为评估拇外翻的临床工具的潜在用途。
