Varner Kevin E, Matt Victoria, Alexander Jerry W, Johnston James D, Younas Shiraz, Marymont John V, Noble Philip C
The Methodist Hospital, Department of Orthopaedic Surgery.
Foot Ankle Int. 2009 Feb;30(2):142-9. doi: 10.3113/FAI-2009-0142.
Hallux valgus associated with metatarus primus varus is a deformity that disrupts normal foot function. Standard treatment has often included distal or proximal metatarsal osteotomy with or without a distal soft tissue procedure. The intrinsically unstable proximal crescentic osteotomy relies on operative fixation for stability. This study examined the strength of fixation of a single screw versus a plate for stabilization of proximal first metatarsal crescentic osteotomies for correction of hallux valgus.
A crescentic osteotomy was performed on nine pairs of fresh/frozen cadaveric feet. The distal fragment was rotated laterally and the osteotomy was temporarily stabilized with a Kirschner wire. The osteotomized metatarsal fragments were fixed with a cancellous screw on one side and single plate on the contralateral side. Each specimen was loaded in a mechanical testing machine, and its response was measured by monitoring the opening of the osteotomy and change in alignment of the fragments. Position and alignment of the proximal and distal fragments were calculated.
All of the measures of fixation strength were statistically greater in specimens treated with a plate rather than with screw fixation. Plate fixation provided approximately twice the resistance to disruption of the osteotomy under cyclic loading conditions.
The dorsal plate is biomechanically more stable than a single cancellous screw when applied to proximal crescentic osteotomies.
The greater stability of the plate construct may be helpful in selecting the fixation device for these osteotomies.
拇外翻合并第一跖骨内翻是一种破坏足部正常功能的畸形。标准治疗通常包括行远端或近端跖骨截骨术，可伴或不伴远端软组织手术。本质上不稳定的近端新月形截骨术依靠手术固定来维持稳定。本研究比较了单枚螺钉与钢板用于稳定近端第一跖骨新月形截骨术以矫正拇外翻的固定强度。
对9对新鲜/冷冻尸体足行新月形截骨术。将远端骨块向外旋转，截骨处以克氏针临时固定。截骨后的跖骨骨块一侧用松质骨螺钉固定，另一侧用单钢板固定。每个标本在机械试验机上加载，通过监测截骨处的开口及骨块对线的变化来测量其反应。计算近端和远端骨块的位置和对线情况。
用钢板治疗的标本，其所有固定强度指标在统计学上均高于用螺钉固定的标本。在循环加载条件下，钢板固定对截骨处破坏的抵抗力约为螺钉固定的两倍。
应用于近端新月形截骨术时，背侧钢板在生物力学上比单枚松质骨螺钉更稳定。
钢板结构更高的稳定性可能有助于为这些截骨术选择固定装置。
