Limb Preservation and Deformity Correction Fellow, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD.
Resident Physician, Department of Plastic Surgery, MedStar Georgetown University Hospital, Washington, DC.
J Foot Ankle Surg. 2022 Sep-Oct;61(5):986-990. doi: 10.1053/j.jfas.2021.12.025. Epub 2021 Dec 22.
Intramedullary screw fixation is a well-established surgical treatment for fifth metatarsal Jones fractures, due to its minimally invasive nature, and potential early return to activity. Due to the curvature of the fifth metatarsal, optimal length of the screw is needed to prevent gapping at the fracture site. The placement of a straight screw induces straightening of a naturally curved bone. The purpose of this study was to aid surgeons in determining an appropriate screw length for intramedullary fixation of a fifth metatarsal Jones fracture in order to prevent fracture gapping. A transverse osteotomy of the fifth metatarsal was made in 10 cadaver specimens at the level of a traditional Jones fracture. Inserted screws were sequentially increased in length until plantar gapping at the fracture site was noted. The angle (degree) of plantar gapping was measured with each increase in screw length and diameter. The mean length of the cadaveric fifth metatarsals was 73.76 mm (range 67.42-81.73). The mean screw length that caused gapping at the fracture site was 49.89 mm (range 44-55), representing 67.05% (range 61.26-75.35) of the fifth metatarsal length. The correlation coefficient revealed that gapping of the fracture site is most likely to occur when the screw length is 66% the length of the metatarsal length (r = 0.66; 95% confidence interval: 0.06-0.91; p = .04). The angle of the initial gapping was 2.85° (range 2°-4°). With an incremental increase in screw length, the angle was 3.85° (range 3°-6°), and with an incremental increase in screw diameter, the angle was 3.70° (range 2°-5°). Our study demonstrated that screw lengths exceeding 66% of the metatarsal length lead to plantar fracture gapping. Additionally, gapping was accentuated with larger diameter screws due to angle variance.
髓内钉固定是治疗第五跖骨 Jones 骨折的一种成熟的手术治疗方法，因为它具有微创性和潜在的早期活动恢复能力。由于第五跖骨的弯曲，需要合适长度的螺钉以防止骨折部位出现间隙。直螺钉的放置会导致自然弯曲的骨头变直。本研究旨在帮助外科医生确定第五跖骨 Jones 骨折髓内固定的合适螺钉长度，以防止骨折间隙。在 10 具尸体标本的第五跖骨水平处进行横形骨切开术，即传统 Jones 骨折处。插入的螺钉依次增加长度，直到在骨折部位观察到足底间隙。随着螺钉长度和直径的增加，测量足底间隙的角度（度）。尸体第五跖骨的平均长度为 73.76 毫米（范围 67.42-81.73）。导致骨折部位出现间隙的平均螺钉长度为 49.89 毫米（范围 44-55），占第五跖骨长度的 67.05%（范围 61.26-75.35）。相关系数表明，当螺钉长度为跖骨长度的 66%时，骨折部位最有可能出现间隙（r = 0.66；95%置信区间：0.06-0.91；p = 0.04）。初始间隙的角度为 2.85°（范围 2°-4°）。随着螺钉长度的递增，角度为 3.85°（范围 3°-6°），随着螺钉直径的递增，角度为 3.70°（范围 2°-5°）。我们的研究表明，螺钉长度超过跖骨长度的 66%会导致足底骨折间隙。此外，由于角度变化，较大直径的螺钉会加重间隙。
