1、of thediaphysisfifth metatarsalfoot. The fifth metatarsal is at the base of the smalltoe. Theproximal end, where the Jones fracture occurs, is in the midportion of the foot. Patients who sustain a Jones fracture havepainover this area,swelling, and difficulty walking. The fracture was first describe
2、d byBritishorthopedic surgeonSirRobert Jones, who sustained this injury himself while dancing, in theAnnals of Surgeryin 1902. Fractures of the fifth metatarsal of the foot are surprisingly controversial among radiologists, particularly concerning proximal metatarsal fractures. Some term these fract
3、uresJones fractures, othersdancers fractures, while others simply term themproximal metatarsal fractures. According to Orthopedic Radiology （Adam Greenspan, 3rd edition）, a true Jones fracture occurs one inch distal to the base of the fifth metatarsal. It isnot due to peroneus brevis tendon avulsion
4、 but rather a twisting inversion injury to the foot. Greenspan states that more proximal injuries are frequently misinterpreted as Jones fractures but really are avulsion fractures by the peroneus brevis tendon. These latter fractures heal quickly, while more distal fractures may undergo fibrous uni
5、on only.A patient stepped off a curb and sustained a fracture of the proximal aspect of the fifth metatarsal. According to Greenspan, this would be termed a true Jones fracture.In contradistinction, this patient sustained a fracture of the proximal aspect of the fifth metatarsal. Greenspan terms thi
6、s an avulsion injury.In an avulsion fracture, a small piece of bone is pulled off the main portion of the bone by a tendon or ligament. This type of fracture is the result of an injury in which the ankle rolls. Avulsion fractures are often overlooked when they occur with an ankle sprain.Treatment：If
7、 a Jones fracture is not significantly displaced, it can be treated with acast, splint or walking boot for four to eight weeks. Patients should not place weight on the foot until instructed by their doctor. Three-fourths of fractures treated like this should heal.In the case of acute fracture in an
8、athlete, a dynamic compression plate can be placed on the tension side of the fracture, K-Wire with Monofiament wire in a figure 8 fashion due to the nature of a transverse fracture. Internal fixation with cortical or cancellous screw would require an oblique fracture that could be addressed through
9、 The rule of 2s in regards to Internal fixation with screws.Other treatments commonly encouraged are increased intake ofvitamin Dandcalcium.This injury must be differentiated from the physiologic developmentalapophysiscommonly and normally occurring at this site in adolescents. Differentiation is po
10、ssible by characteristics such as absence of sclerosis of the fractured edges （in acute cases） and orientation of the lucent line: transverse （at 90 degrees） to the metatarsal axis for the fracture （due to avulsion pull by the peroneus brevis muscle inserting at the proximal tip） - and parallel to t
11、he metatarsal axis in the case of the apophysis.Jones fractures can become chronic conditions if the fracture fails to unite, or heal. If this is the case, surgery will likely be recommended to secure the fracture in place with a screw, and bone graft may be used to stimuate a healing response.- Sur
12、gical Treatment: （Jones Frx）; - patient is position in partial lateral position on bean bag; -flouroscopy: - under flourscopicguidence, a K wire is inserted for determination of proper position and length;most common mistake is to direct the drill plantarly, rather than parallel w/ the shaft of meta
13、tarsal;second mistake is too position the guide wire using the oblique view;- note that the metatarsal shaft is more narrow on the AP view, and it ispossible for the pin to be centered on the oblique view where as on AP view the pin is eccentrically positioned;incision: - longitudinal incision is ma
14、de over distal metatarsal; - take care to avoid branches of the sural nerve which can course dorsally, and laterally over metatarsal; - peroneus brevis is retracted inferiorly;insertion of this tendon may obscure the proper drill entry site;local bone graft: - can be obtained from tuberosity and fro
15、m bone bits from the drill;implants: - consider insertion of4.5 cancellous bone screws,4.5 mm cannulated screws （which are used in most cases） but haveavailable 5.5 cannulated （and solid）screws and 6.5 mm cannulated screws;- diameter should depend on width of the canal （let the screw tap help determ
16、ine the best size）; - in either case, threads must cross the frx line; - length is usually between 40-55 mm; - consider countersinking the screw to avoid prominence of the screw head; - inreport by IP Kelly,authors noted that failure is more likely when smaller diameter screwsare used;- experimental
17、 Jones fractures were created in 23 pairs of human cadaver fifth metatarsals, which were fixed using either 5.0 mm or 6.5 mm screws;- frx stiffness and pull-out strengths were measured for either screw type andrelationships with bonedensity andcanal diameter were determined;- poor thread purchase wi
18、thin the medullary canal was noted with the 5.0 mm screws, while excellent purchase was noted with 6.5 mm screws;- pull-out strength testing revealed significantly higher pullout strengths for the larger 6.5 mm screws;- the authors conclude that larger diameter screws may be more appropriate for int
19、ramedullary screw fixation of Jones fractures;- ref: Treatment of Jones Fracture Nonunions and Refractures in the Elite Athlete Outcomes of IM Screw Fixation With Bone Grafting-post op: patients willrequire protected postoperativewt bearing;1、解剖方面考虑：恢复跖骨头的队列关系是非常重要的前足的力学目标：如下图示：在正位，应是“顺流而下”的表现，且与对侧足
20、对称，这是恢复正常跖骨长度的保证。另一个需要恢复的重要结构是跖骨水平线，需保持其均在一个水平线上。需要注意的是，在第一跖骨，是籽骨在承重，而不是第一跖骨头，因此，序列对应关系应与籽骨为准。任何力线改变均可引起站立相和推离相时疼痛及胼胝形成。2、螺钉或钢板固定：固定这种骨折，因尽可能使其稳定。横行骨折线时，单独拉力螺钉固定即可。3、手术入路：详见后。4、复位：骨折在直视下复位，因为其为横形骨折，复位满意后用复位钳保持复位。5、拧入螺钉：从腓骨短肌肌腱止点处，稍向内侧倾斜方向打入导针，这样可以抓住远骨折端的内侧骨皮质，增加稳定。骨折近端应做成滑动孔，以允许骨折块间加压，螺钉直径应根据骨情况来选择，
21、常选用3.5或4.0mm螺钉固定。6、另一种固定方式：髓内螺钉固定：选髓内螺钉固定，螺钉直径要与髓腔匹配，螺钉必须有充足直径以获得稳定加压固定，根据髓腔的大小，可选用3.5或4.5mm皮质螺钉固定，在体型高大患者，可能需用6.5mm松质骨螺钉固定。1、注意保护血运：避免广泛深度暴露、过度牵拉；多个跖骨骨折应采用单独切口，避免增加软组织损伤；在足部保护静脉回流是非常重要的。2、解剖：小隐静脉位于切口部位的皮下；在静脉的深面是小趾外展肌；腓肠神经（与小隐静脉伴行）的分支应给予保护。3、皮肤切口：切口开始于可触及的第5跖骨茎突处，依据需要向远端延伸。切口要位于足部掌侧皮肤与背侧皮肤的交界处。4、深层分离：显露第5小趾外展肌筋膜，并纵向切开。5、骨质显露：使用拉钩，向背侧牵开皮肤及背侧筋膜，向掌侧牵开肌肉，显露第5跖骨基底。
