肱桡关系的再认识

1959年，Storen首次提出了肱桡关系（radiocapitellarline，RCL），在肘关节侧位X线，桡骨纵轴的延长线通过肱骨小头中心，并建议肱桡关系有助于诊断儿童创伤，但是Storen没有具体描述纵轴线是经过桡骨颈还是桡骨干[1]。

尽管肱桡关系（radiocapitellar line，RCL）最常用于儿童肘关节创伤的诊断，但也同样适用于成人肘关节创伤的诊断，新版《AO surgery reference》也强调了成人正常肘关节存在“the axis of the proximal radialshaft is aligned with the center of the capitellum”。通过桡骨干中点的纵轴线没有通过在正常位置的肱骨小头中点，常见于哪些病变？我刚参加工作时，老师教我：异常的肱桡关系见于下列四种病变：肱骨外髁骨折、桡骨颈骨折、Monteggia损伤和肘关节脱位。随着临床工作时间的延长，不仅理解了肘关节后脱位仅仅是肘关节后外侧旋转不稳定的一个病理阶段（O’Driscoll，1991年），而且也诊治了软组织嵌顿源性单纯桡骨头创伤性前脱位、crisscross 损伤、先天性桡骨头前脱位等非常罕见的病例。肱桡关节关系异常不仅见于老师教我的四种疾病，也见于软组织嵌顿源性单纯桡骨头创伤性前脱位、crisscross 损伤和先天性桡骨头前脱位。

肱桡关系（radiocapitellar line，RCL）目前存在的争议是：(1)桡骨纵轴的延长线如何画？纵轴线是通过桡骨颈[2, 3]？通过桡骨干[4, 5]？通过[6]？(2)在肘关节哪个X线投照体位测量更准确？正位和侧位都准确[4, 5, 7]？只有侧位准确[3, 8, 9]？(3)延长线是否一定经过肱骨小头中点？(4)肱桡关系是否与患者年龄、性别有关？肱桡关系是否同样适用于成年患者？

[1]Storen G. Traumaticdislocation of the radial head as an isolated lesion in children; report of onecase with special regard to roentgen diagnosis. Acta Chir Scand, 1959, 116(2):144-147.

[2] Snyder HS. Radiographic changes with radial headsubluxation in children. J Emerg Med, 1990,8(3): 265-269.

[3] Stanley EA DJF, Beaty JH, Kasser JR. Monteggiafracturedislocation in children. In: JH Beaty, JR Kasser, eds. Rockwood and Wilkins’ Fractures in Children. 6th ed. Philadelphia:Lippincott Williams & Wilkins; 2001:529-562.

[4] Cone RO. Clues to the initialradiographic evaluation of skeletal trauma. Emerg Med Clin North Am, 1984, 2(2): 245-278.

[5] Frumkin K. Nursemaid's elbow: aradiographic demonstration. Ann Emerg Med, 1985, 14(7):690-693.

[6] Wang C, Su Y. An Alternative to the TraditionalRadiocapitellar Line for Pediatric Forearm Radiograph Assessment in MonteggiaFracture. J Pediatr Orthop, 2020, 40(3):e216-e221.

[7] Weisman DS, Rang M, Cole WG. Tardydisplacement of traumatic radial head dislocation in childhood. J Pediatr Orthop, 1999,19(4):523-526.

[8] Miles KA, Finlay DB. Disruption ofthe radiocapitellar line in the normal elbow. Injury, 1989, 20(6): 365-367.

[9] Price CT, Flynn JM.“Management of fractures.”Lovell and Winter’s Pediatric Orthopedics. 6th ed. Philadelphia, PA: Lippincott Williams andWilkins; 2006:1495–1496.