Metatarsal Fractures PDF

M e t a t a r s a l F r a c t u res a, b Donald E. Buddecke, DPM *, Matthew A. Polk, DPM , Eric A. Barp, DPMc KEYWORDS  Metatarsal  Fracture  Jones  Injury Acute metatarsal fractures represent a common cause o...

M e t a t a r s a l F r a c t u res a, b Donald E. Buddecke, DPM *, Matthew A. Polk, DPM , Eric A. Barp, DPMc KEYWORDS  Metatarsal  Fracture  Jones  Injury Acute metatarsal fractures represent a common cause of forefoot pain, accounting for 35% of all foot fractures and 5% of total skeletal fractures.1 These fractures may occur as an isolated injury, concurrently with fractures of additional metatarsals, or in conjunction with Lisfranc injuries. Both direct and indirect traumas have been implicated in metatarsal fractures. Although most metatarsal fractures are a result of low-energy trauma,2 high-energy crush injuries do occur with some frequency. As with other high-energy fractures, the soft tissue enve- lope becomes the primary concern (Fig. 1). These crush injuries need to be eval- uated for compartment syndrome, and definitive treatment of the osseous component is delayed until the pressures are addressed. The recovery and condi- tion of the soft tissue envelope then dictates when the definitive treatment is performed. Metatarsal fractures can occur at any location on the bone and are generally divided by the region of occurrence into proximal metaphyseal (Fig. 2), diaphyseal or shaft (Fig. 3), and head and neck fractures (Fig. 4). Proximal metaphyseal and metatarsal base fractures may be associated with Lisfranc dislocations. These frac- tures often stay relatively well aligned because of the numerous articulations and soft tissue attachments.2–4 Diaphyseal fractures are often oblique but may present in several fracture patterns. These fractures should be evaluated for shortening, angulation, and displacement.5 In addition, stress fractures can progress to complete transverse fractures, and subsequent angulation or translation is a concern (Fig. 5). Distal metaphyseal fractures are commonly transverse or oblique, and if displacement is present, it typically occurs plantarly and laterally.6 Because of the unique function of the first and fifth rays and the commonality between the central metatarsals, it is useful to examine metatarsal fractures in these separate compo- nents: first metatarsal, central metatarsals (including second, third, and fourth), and fifth metatarsal. a Private Practice, 10780 V Street, Omaha, NE 68127, USA b Saint Joseph Hospital, 2900 North Lakeshore Drive, Chicago, IL 60657, USA c Private Practice, 5950 University Avenue, Suite 160, West Des Moines, IA 50266, USA * Corresponding author. E-mail address: [email protected] Clin Podiatr Med Surg 27 (2010) 601–624 doi:10.1016/j.cpm.2010.07.001 podiatric.theclinics.com 0891-8422/10/$ – see front matter Ó 2010 Elsevier Inc. All rights reserved. 602 Buddecke et al Fig. 1. Crush injury, showing damage to the soft tissue envelope. FIRST METATARSAL The importance of the first metatarsal and first ray has been previously reported.7–10 A traumatic disruption of the function or integrity of the first metatarsal can disturb the normal gait and cause pain at the first metatarsophalangeal joint, proximally along the medial column, or at the lesser metatarsals,3,11 which can also lead to gait distur- bances that can affect the entire limb. The first metatarsal is the thickest, strongest, shortest, and heaviest of the meta- tarsal bones and has been reported to be the least frequently fractured metatarsal in adults, with an incidence of 1.5% of all metatarsal fractures.1,11 However, a higher rate of fracture of the first metatarsal has been noted in pediatric populations, Fig. 2. Nondisplaced fractures of the central metatarsal bases.  Metatarsal Fractures 603 Fig. 3. Diaphyseal fractures of the second to fifth metatarsals. Fig. 4. Metatarsal neck fracture with malalignment of the third metatarsal. Also noted are fractures of the second metatarsal shaft and proximal phalanx of the third toe. 604 Buddecke et al Fig. 5. Stress fracture of the second metatarsal that has progressed to complete fracture with malalignment. especially in children younger than 5 years, whose injuries are more likely to have resulted from a fall from a height.12 Anatomically, the posterior aspect of the first metatarsal is large and concave, with a large kidney-shaped articular surface for its articulation with the medial cuneiform. The head of the first metatarsal is completely covered by articular cartilage for articu- lation with the proximal phalanx distally and the sesamoids plantarly. The first meta- tarsal motion is independent of the other metatarsals, allowing adaptability to uneven surfaces and ability to work in conjunction with hindfoot motion and variability. The first metatarsal is supplied by the dorsal metatarsal artery, the first plantar meta- tarsal artery, and the superficial branch of the medial plantar artery. The nutrient artery enters laterally in the distal one-third of the metatarsal, most often originating from the first dorsal artery.3,11 In the normal foot, there is equal distribution of weight across 6 different anatomic locations of the forefoot. Each of the lesser metatarsal heads along with the 2 sesa- moids accommodates one-sixth of the weight during normal gait.13 The importance of the first metatarsal is noted with its need to accommodate more pressure than the other metatarsals. Morton10 noted that the axes of the forefoot were in balance when half of the weight passed through the first and second metatarsals and the other half of the weight passed through the third, fourth, and fifth metatarsals. Any disruption of this balance can lead to a dysfunctional foot. The most frequent mechanism of injury of the first metatarsal in adults is either a standing fall or a direct blow, with the fracture most likely occurring in the diaphysis of the bone.2 Twisting injuries, related to falls, occur when the foot is fixed on the ground and a sharp turn produces a mediolateral torque, which fractures the meta- tarsal. Axial loads may also cause a fracture by impacting the metatarsal into the medial cuneiform.3,11 Direct crush injuries have been noted to be common in industry  Metatarsal Fractures 605 and often produce open fractures.14 Avulsion fractures may occur at the first meta- tarsal base with plantar flexion and inversion type injuries because of the attachments of the peroneus longus and tibialis anterior at this level.3,11 CENTRAL METATARSALS Central metatarsal fractures occur much more frequently than first metatarsal frac- tures and are more likely to affect multiple metatarsals. It has been reported that 63% of third metatarsal fractures occurred concurrently with second or fourth meta- tarsal fractures and 28% with both.2 Petrisor and colleagues2 also noted that all cases of multiple metatarsal fractures occurred in contiguous bones, so a careful radio- graphic examination is warranted when an isolated metatarsal fracture is encountered. The central metatarsal bases bear joint surfaces for articulation with the tarsal bones. The second metatarsal articulates with all 3 cuneiform bones and is addition- ally stabilized by the Lisfranc ligament, which runs between the medial cuneiform and the base of the second metatarsal. The remaining metatarsal bases are joined by strong ligamentous support, both dorsally and plantarly. No similar structure uni- tes the first and second metatarsals, allowing the first metatarsal its independent motion. As previously mentioned, the bases of the central metatarsals are also stabilized by plantar, dorsal, and interosseous ligaments. Slips from the tibialis posterior represent the only extrinsic attachment. The metatarsal shafts are the origin for the intrinsic plantar and dorsal interossei.1 The primary nutrient artery of the central metatarsals enters laterally, approximately 3.1 cm from the distal articular cartilage.15 Central metatarsal fractures are caused by indirect torsional trauma or direct trauma, with most fractures being attributed to the latter.1,2 Direct trauma includes crushing blows to the dorsum of the foot or penetrating injuries (ie, gunshot wounds). Indirectly, a spiral or oblique fracture may be produced by a twisting injury over a fixed forefoot. Because of the relative lack of motion, soft tissue attachments, and stable proximal articulations, these fractures have a level of intrinsic stability. However, when displacement occurs, the central metatarsals are more likely to displace as a unit.1,2 FIFTH METATARSAL The fifth metatarsal is the most frequently fractured, with a reported rate of up to 68% of all metatarsal fractures.1 Similar to the first metatarsal, the fifth metatarsal functions with motion independent of the central metatarsals. The fifth metatarsal is also unique in that it has a proximal tuberosity for the insertion of the peroneus brevis tendon and the lateral slip of the plantar fascia. The tendon of the peroneus tertius also inserts into the dorsal aspect of the shaft. The fifth metatarsal base articulates with the cuboid proximally and with the fourth metatarsal base medially, with strong ligamentous attachments to both. The flexor digiti minimi and dorsal and plantar interossei originate from the fifth metatarsal.16–19 Vascularity is provided by the dorsal metatarsal, the plantar metatarsal, and the fibular plantar marginal arteries. Investigations into the vascular supply of the fifth metatarsal indicate a poor blood supply to the proximal diaphysis, which may be associated with poor healing of fractures in this area.17,20,21 Fractures of the fifth metatarsal have a much greater emphasis on the anatomic location. Fifth metatarsal fractures are classified into head and neck fractures, shaft fractures, and fractures occurring at the base. Metatarsal neck fractures can be trans- verse, spiral, or impaction fractures (Fig. 6). Most fractures maintain an acceptable 606 Buddecke et al Fig. 6. Fracture of the fifth metatarsal neck with extension into the diaphyseal portion of bone. alignment, but excessive sagittal plane displacement should be addressed because of weight-bearing considerations. Metatarsal shaft fractures are typically spiral. These fractures often have an associated butterfly fragment but can also present with signif- icant comminution (Fig. 7). Comminuted fractures are usually related to direct impact or less-than-optimal bone quality. Both metatarsal neck and shaft fractures should also be evaluated for shortening.16–18 Fractures occurring at the base of the fifth metatarsal are of biggest concern because of the high incidence of tuberosity avulsion fractures and the controversy regarding fractures of the metaphyseal-diaphyseal junction. The fifth metatarsal avul- sion fracture may be intra-articular (Fig. 8) or extra-articular. Traditionally, the avulsion fracture was thought to be caused by a violent contracture of the peroneus brevis tendon, but recent findings have implicated the lateral band of the plantar aponeurosis (Fig. 9) as the cause of the fracture.22 It is likely that both structures can be implicated in isolation or in combination. At any rate, the mechanism is an inversion type of injury. Possible differential diagnoses of fifth metatarsal avulsion fractures include the pres- ence of an apophysis in children and os peroneum or os vesalianum in adults, which is usually not difficult to determine based on clinical examination. In addition to avulsion fractures, fifth metatarsal base fractures are further divided into acute (Fig. 10) metaphyseal-diaphysealfractures (Jones fractures) and proximal diaphyseal stress fractures. Fractures occurring distal to the fifth metatarsal base at the metaphyseal-diaphyseal junction are typically referred to as the Jones fractures. These fractures can be difficult to distinguish from the proximal diaphyseal stress frac- tures that occur in the same area. The differentiating factors include the acute injury causing the Jones fractures versus the existence of prodromal symptoms in stress fractures. Occasionally, the development of an acute-on-chronic injury occurs. This  Metatarsal Fractures 607 Fig. 7. Fracture of the fifth metatarsal shaft with associated comminution. injury is seen in the presence of prodromal symptoms, but then a specific traumatic injury is reported by the patient. In this scenario, it is likely that the stress reaction or stress fracture was developing and the acute injury allowed the fracture to occur. The radiographic appearance can reveal signs of a chronic fracture/stress fracture despite the acute injury (Fig. 11). These junctional fractures of the fifth metatarsal were further detailed by Torg and colleagues23 These investigators studied 46 junctional fractures and divided them into acute fractures (those with a narrow fracture line and absence of medullary scle- rosis), fractures with delayed union (those with widening of the fracture line and some Fig. 8. Avulsion fracture of the fifth metatarsal with intra-articular involvement. 608 Buddecke et al Fig. 9. Avulsion fracture of the fifth metatarsal base with displacement. This fracture was likely caused by pull of the lateral band of the plantar aponeurosis as opposed to that of the peroneus brevis, which would usually involve a larger fracture fragment because of the expansive attachment of this tendon. evidence of medullary sclerosis), and fractures with nonunion (those with complete obliteration of the medullary canal by sclerotic bone).23 The acute junctional fracture was initially described in 1902.24 Later, Stewart25 dis- cussed the decreased healing potential of these fractures and developed a classifica- tion system for describing the proximal fifth metatarsal fractures. He defined the Jones fracture as a transverse fracture at the metaphyseal-diaphyseal junction.25 The cause Fig. 10. Acute fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal base (Jones fracture).  Metatarsal Fractures 609 Fig. 11. This patient presented with an acute presentation after a traumatic event. However, radiographs reveal evidence of bony callus formation, suggesting previous injury or stress fracture. After specific questioning of the patient, there was evidence of prodromal symp- toms even before the injury. of this fracture is thought to be a large adduction force applied to the forefoot while the ankle is plantar flexed. The fracture site corresponds to the area between the insertion of the peroneus tertius and peroneus brevis tendons. Hindfoot varus has been identi- fied as a possible predisposing factor to Jones fractures.16,17,24,25 A varus attitude of the calcaneus certainly predisposes the lateral column of the foot to increased force, making it a contributing factor in stress fractures of the fifth metatarsal and, on occa- sion, the fourth metatarsal (Fig. 12). TREATMENT First Metatarsal Fractures Strict attention to detail must be maintained in addressing the first metatarsal fractures because significant forces exist through the first metatarsal during gait. Any consider- able displacement may have detrimental effects on the hallux through the metatarso- phalangeal joint, causing gait abnormalities. Misalignment in the sagittal plane may limit the dorsiflexory/plantarflexory motion through the joint, causing traumatically induced hallux limitus/rigidus. Any sagittal plane malalignment is likely to lead to 610 Buddecke et al Fig. 12. (A) Radiographs demonstrating healing fractures of the fourth and fifth metatar- sals. Associated metatarsus adductus deformity can be noted. (B) Mortise radiograph of the same patient demonstrating the varus attitude of the calcaneus placing an increased pressure on the lateral column of the foot. metatarsalgia (Fig. 13). In addition, the hindfoot tries to compensate for this malalign- ment, often leading to additional foot or limb dysfunction. Significant displacement in the transverse plane may have the undesired effects of hallux valgus or varus. Frontal plane deformities are rare. Additional malalignment that often leads to a dysfunctional foot is shortening of the first metatarsal. Any loss of length needs to be restored to maintain the normal metatarsal parabola. Criteria for surgical management of the fracture depend on the stability of the frac- ture. Anatomically, there is no ligamentous support from the first metatarsal to the lesser metatarsals. Fractures that display instability and displacement warrant surgical intervention. Nondisplaced fractures may be treated as per surgeon preference. Most of the literature supports a period of non–weight bearing in either a cast or a CAM boot Fig. 13. (A) Anteroposterior radiograph showing an apparent nondisplaced first metatarsal shaft fracture. (B) Lateral radiograph of the same patient indicating plantar flexion of the distal portion of the first metatarsal.  Metatarsal Fractures 611 for at least 2 to 3 weeks, with protective weight bearing to follow until radiographic evidence of healing is noted.26,27 Truly nondisplaced fractures of the first metatarsal are rare, and close radiographic follow-up is necessary to ensure that alignment is maintained throughout the conservative therapy. Because of the force required to cause a fracture of this bone and the relative lack of stabilizing structures some displacement and malalignment is usually encountered. Techniques for fixation of the first metatarsal depend on the fracture pattern. For diaphyseal fractures, buttress plating with screw fixation is the standard of care. The goals of internal fixation are to allow good bony apposition while restoring the osseous architecture. Strict attention to the length of the metatarsal, sesamoid appa- ratus, anatomic features of the metatarsophalangeal and tarsometatarsal joints, and planar alignment is paramount. Fixation of the fracture on the medial aspect may be done to protect the extensor tendons dorsally. The ideal position of plate fixation would be on the plantar aspect because this is the tension side of the fracture. However, dorsal or medial plate fixation is more common because of dissection restraints. If there is significant comminution of the first metatarsal that would not support internal fixation, external fixation is warranted. The goal is to maintain the length of the first metatarsal to prevent transfer metatarsalgia. Patients with injuries involving severe comminution typically have damage to the soft tissue envelope as well. The application of external fixation is an option to protect the soft tissue envelope while maintaining stability of the fracture, further aiding in soft tissue repair. External fixation can span the first metatarsophalangeal joint and/or the first tarsometatarsal joint as deemed necessary for strength. This joint-spanning technique can also be used with plate fixation. The typical scenario is a comminuted fracture at the metatarsal base in which solid fixation cannot be accomplished. Surgeon’s discretion dictates when joint-spanning techniques are to be used. Management of intra-articular first metatarsal head fractures should attempt to preserve the integrity of the joint. If any joint incongruity is noted, open reduction with internal stabilization is mandated for a positive functional outcome. For meta- tarsal head fractures with significant impaction, cancellous bone grafting may be used. In isolated cases of significant comminution, primary metatarsophalangeal joint arthrodesis may be considered. Such cases are not commonly encountered. Complications after first metatarsal fractures can include malunion, nonunion, and posttraumatic arthrosis. As mentioned previously, malunion can lead to not only local problems but also problems with dysfunction of the forefoot, midfoot, hindfoot, ankle, or entire limb. Nonunion after a first metatarsal fracture is not common. The healing potential is high because of the large percentage of cancellous bone relative to diaph- yseal bone. Similar to other fractures involving joints, the incidence of arthrosis depends on the amount of damage at the time of injury and the quality of reduction of joint surfaces. Central Metatarsal Fractures As with almost all other fractures, nondisplaced or minimally displaced fractures of the central metatarsals are amenable to nonoperative treatment, including protected mobilization or immobilization in a cast, CAM boot, or even stiff-soled shoe. Accept- able levels of displacement or angulation of fractures vary depending on the treating physician. Although no definitive study is available to guide the decision making with regard to displacement or angulation, commonly acceptable levels have been reported to be less than 10 of angulation13,28 and only 3 or 4 mm of translation in any plane.29,30 Displacement in the sagittal plane is the least tolerated and can lead 612 Buddecke et al to excessive pressure if the fracture is plantarly displaced or angulated. Also, dorsally angulated fractures can cause dorsal or transfer irritation plantarly at the adjacent metatarsals. Transverse plane malalignment is better tolerated but can cause irritation as well. Close abutment of the metatarsal heads can lead to irritation with ambulation or even cause an intermetatarsal neuroma. Frontal plane malalignment is typically not a concern. The attachments between the metatarsal heads make frontal plane displacement an uncommon finding. The goal of treatment is to maintain a functional forefoot. Specific details that should be considered for healing to take place include the metatarsal parabola, the sagittal plane position of the metatarsal heads, and bone-to-bone contact (Fig. 14). Closed manipulation of fractures of the central metatarsals can be accomplished with distal traction. However, one should be prepared to proceed with open reduction because maintaining the reduction with a closed means in a fracture with significant displace- ment is often an exercise of futility. In patients with significant comorbidities or vascular compromise, attempts are certainly warranted. In addition, the surgeon should be prepared for percutaneous pinning in cases in which reduction can be diffi- cult to maintain. Percutaneous Kirschner (K)-wire pinning can be performed with a variety of tech- niques. A common method is intramedullary pinning through the corresponding meta- tarsal head, which is usually done with a single K-wire fixation down the medullary canal, crossing the fracture site, and occasionally crossing the tarsometatarsal artic- ulation when additional stability is deemed necessary. Additional K wires can be used for added strength but are rarely necessary. With multiple metatarsal fractures, the most displaced fracture is reduced and stabilized, often leading to anatomic, or near anatomic, restoration of the adjacent metatarsal fractures and eliminating the need for further fixation (Fig. 15). If displacement is maintained, additional manipula- tion can be performed followed by additional pinning. Alternative percutaneous pinning options have been described, including transverse pinning of the metatarsal heads.31 Advantages of percutaneous pinning include the ability to maintain vascu- larity to the fractured bone. No extensive dissection is used, and subsequently, the soft tissue envelope is not disrupted. The main disadvantage is the inability for direct visualization and manipulation of the fracture. Thus, these advantages and disadvan- tages need to be weighed for each fracture. When manipulation is not successful with closed means, open procedures are per- formed. Minimally invasive options are available depending on the fracture attitude. The theoretical advantage to the minimally invasive approach is the ability for direct visualization and manipulation of the fracture without extensive soft tissue stripping. A small incision can be placed over the fracture site to allow this visualization and manipulation. The distal fragment is then plantar flexed, giving access for insertion of the K wire down the medullary canal, which is then advanced distally through the metatarsal head. The toe is dorsiflexed, allowing the K wire to exit plantarly. A slightly modified technique has been described, which includes pinning across the proximal phalanx and exiting plantar to this bone.13 The fracture is then reduced, and the K wire retrograded back across the fracture site, thus providing stability. The drawback, as with the percutaneous intramedullary fixation described earlier, is some disruption of the metatarsophalangeal joint and the potential for injury to the flexor tendons. However, it is unknown if this drawback has any long-term ill effect on the patient. Standard open reduction with internal fixation is also an option for the treatment of central metatarsal fractures. This procedure has the advantage of direct visualization of the fracture, and thus, complete anatomic reduction should be easier. In addition, this procedure allows for more stable fixation options. However, this approach does  Metatarsal Fractures 613 Fig. 14. (A, B) Anteroposterior and lateral radiographs demonstrating disruption of the metatarsal parabola with shortening of the second metatarsal and sagittal plane malalign- ment. Arthrosis is present at the first tarsometatarsal joint. This arthrosis led to the forefoot dysfunction and was the cause of the second metatarsal fracture. (C–E) Radiographs demon- strating reestablishment of the metatarsal parabola and realignment of the fracture in the sagittal plane. Although the first tarsometatarsal joint arthrosisand the fact that it was the cause of the second metatarsal stress fracture were discussed with the patient, the patient refused treatment of this joint. 614 Buddecke et al Fig. 15. (A) Shaft fractures of the central metatarsals. The maintenance of alignment of the third metatarsal can be noted. (B) K-wire fixation of the second and fourth metatarsals, showing complete reduction of the fractures and continued alignment of the third metatarsal. lead to the disruption of more of the soft tissue envelope, even with the most meticu- lous dissection. Oblique or spiral oblique fractures may be amenable to interfragmen- tary screw fixation, which is often difficult in central metatarsal fractures because of the adjacent metatarsal making it difficult to manipulate instrumentation in the proper plane. More commonly, dorsal plate fixation is used. Minifragment or small fragment plates can be used, depending on the size of the metatarsal (Fig. 16). Locking plate constructs may also serve the purpose depending on the patient’s condition. Complications are uncommon. The most common complication after closed treat- ment of central metatarsal fractures includes metatarsalgia secondary to malunion and parabola disruption. A delayed union may be encountered, but nonunion is rarely a concern, which the authors think is because of the inherent stability noted within the central metatarsals as well as the musculature surrounding these bones adding to the abundance of vascularity available to promote healing. When a nonunion is noted in a central metatarsal fracture, it is typically the result of a long-standing stress fracture (and subsequently a mechanical problem) and not an acute injury. Fifth Metatarsal Fractures As noted earlier, the most commonly encountered metatarsal fracture is that of the fifth metatarsal. More specifically, the most common location of fracture of this bone is at the base. There exists controversy regarding treatment of fractures in this location. There has been an extensive amount of research regarding treatment of the fifth metatarsal base fracture, with most reports being written about the Jones fracture.24,25,32–49 There is controversy regarding the treatment of Jones fractures because of the difference in recommendations in various patient populations. It has been common to recommend surgical treatment of the Jones fracture in elite athletic populations. Conversely, a recommendation toward more conservative treatment is typically offered to others. However, a trend is developing toward recommending surgical inter- vention not only for elite athletes but also for other active populations and in cases in which a long period of immobilization is not desirable.  Metatarsal Fractures 615 Fig. 16. (A, B) Anteroposterior and lateral radiographs depicting standard plate fixation of a third metatarsal shaft fracture. Jones fractures are notorious for a tendency toward slow healing.24,33–38 Several factors have been implicated for this delay. First, the nutrient artery enters at the medial aspect of this bone in close proximity to the fracture site.20 Subsequently, this fracture has the potential to lead to at least a temporary disruption of this major blood supply.21,35 Second, the metaphyseal-diaphyseal junction is already notorious for a limited vascular supply because of its location distal to the vascular-rich meta- physeal bone. Third, the base of the fifth metatarsal has strong ligamentous attach- ments to the cuboid and fourth metatarsal base. Because of these strong attachments, weight bearing at the metatarsal head causes the lever arm to transfer the forces to the area just distal to these attachments, which corresponds to the site of the fracture. As a result, the potential for motion is high with any weight-bearing activity, even in a fracture shoe or boot. This mechanical issue is the same reason that stress fractures occur in this area. Conservative treatment of Jones fractures typically consists of protected mobiliza- tion in a CAM boot or even non–weight bearing for 6 to 8 weeks. An additional 6 to 8 weeks of normal weight-bearing activity is required before any exercise activity is implemented. Clinical assessment should reveal a lack of pain with direct palpation at the fracture site and signs of trabeculation crossing the fracture before implement- ing exercise activity. Computed tomographic (CT) evaluation may be a viable option 616 Buddecke et al before implementing athletic activity for high-level athletes to ensure complete heal- ing, likely decreasing the chance of refracture. However, with rising concerns of increased exposure to radiation, caution is recommended with the routine use of CT. Numerous reports have demonstrated a tendency for delayed union, higher inci- dence of nonunion, and even refracture with closed treatment of these frac- tures.23,38–40 In a randomized controlled clinical trial, Mologne and colleagues39 demonstrated a significant difference when comparing early screw fixation with casting in acute Jones fractures. In this study, 18 patients were randomized to casting and 19 to intramedullary screw fixation. About 44% of the cast group were considered treatment failures, with 5 cases of nonunion, 1 of delayed union, and 2 of refracture. Only 1 of the 19 patients in the surgical group had a treatment failure (nonunion requiring bone grafting). In addition, the time to union and time to return to sport were almost twice as long in the cast group than in the surgical group. Historically, surgical treatment of this junctional fracture was performed in the patients with delayed union or nonunion. Surgical treatment involved medullary curet- tage and inlay bone grafting. At present, the most common form of surgical treatment is intramedullary screw fixation.39,41,42 This treatment is common for the acute frac- tures as well as for those with delayed union or nonunion. Bone grafting can still be performed when deemed necessary, such as in cases with complete medullary oblit- eration. Numerous reports have demonstrated decreased healing times, earlier return to activity, and less incidence of refracture after intramedullary screw fixation for these junctional fractures.39,41–44 Konkel and colleagues44 reported a 100% satisfaction rate and 98.5% union rate for all fifth metatarsal fractures (including 10 Jones fractures and 2 stress fractures) with only conservative treatment. These investigators, however, recommended “non-operative treatment of fifth metatarsal fractures for patients in whom the time to return to full activities is not critical.” Although intramedullary screw fixation is a common method of fixation, the size and type of screw to be used has been debated. Cannulated screws are commonly used because of the ease of application. The guidewire is easily advanced down the medul- lary canal, and its position confirmed with live fluoroscopy before screw placement. This procedure affords some adjustment in positioning before placement of the screw. However, there is some concern about the strength of cannulated screws versus solid screws. Reese and colleagues45 compared cannulated titanium, cannulated stainless steel, and noncannulated stainless steel screws. They compared different types of 4-mm screws and the number of cycles to failure. The cannulated titanium screw failed after 4308 cycles, the cannulated stainless steel screw after 22,012 cycles, and the noncannulated screw after 44,523 cycles. This result showed an obvious increase in strength with the solid screw. These investigators also noted an increase in the number of cycles to failure with increasing screw size. Another study compared a solid screw developed specifically for Jones fracture fixation with other screws that were typically used for fixation of this fracture (Synthes 4.5-mm Malleolar screw [Synthes Inc, West Chester, PA, USA], Synthes 4.5-mm cannulated screw, and 4/5 Acutrak screw [Acumed Inc, Hillsboro, OR, USA]).46 These investigators noted that the 4.5-mm Carolina screw (solid screw) (Wright Medical Technology Inc, Arlington, TN, USA) exceeded the other screws with regard to load cycles by 27-fold to 7067-fold, depending on the comparison. Reports of screw failure have been documented after intramedullary screw fixation for Jones fractures.33,47 Larson and colleagues47 reported treatment failures in 6 of 15 patients who underwent intramedullary screw fixation, including 4 patients with refrac- ture and 2 with nonunion. Screw sizes used ranged from 4.0 to 6.5 mm. It was reported that 83% of the failures occurred in elite athletes. In addition, the mean time to return  Metatarsal Fractures 617 to activity was 6.8 weeks in the failure group compared with 9 weeks in the success group. Of the 6 failures, only 1 had radiographic confirmation of complete healing. Refracture after intramedullary screw fixation has also been reported. Wright and colleagues34 reported on 6 cases of refracture after intramedullary screw fixation with screws ranging from 4.0 to 5.0 mm. The study population that sustained the refracture included 4 professional football players, 1 collegiate basketball player, and 1 recreational athlete. Of the 6 refractures, 4 were in patients in whom cannulated screws were used. It would seem that this smaller size of screw is inappropriate for such a high-demand patient population. The most appropriate size of screw has not yet been determined. Obviously, the larger-diameter screws will have greater resistance to failure. However, there is a limit to the size of screw that can be used based on the size of the medullary canal. Breakage of the metatarsal shaft has been reported with the use of 6.5-mm screws.46,48,49 As a result, the authors’ method for determining screw size is based on the results of preoperative radiographs. The medullary canal is measured on the anteroposterior, lateral, and oblique views, and the appropriate-sized screw is then used, which typically is a 4.5-, 5.0-, or 5.5-mm screw. Occasionally, a 4.0-mm screw is used in a smaller patient with less physical demands. Several other factors are taken into account when selecting the appropriate-sized screw, including the patient size and patient activity levels. If the size of the medullary canal allows only a smaller-sized screw (ie, 4.0 mm) and the patient is of larger size and/or is active athletically, the time before allowing a return to activity is increased. Also, a solid screw is typically preferred to a cannulated screw. Curvature of the fifth metatarsal needs to be consid- ered as well. Screw length is optimal when all threads are distal to the fracture site and several threads are engaged in the inner cortices of the bone. Care should be taken to prevent penetration of the medial cortex with an excessively long screw. Although it is typically not difficult to have all threads distal to the fracture site with partially threaded screws, extremely curved metatarsals may make it difficult to prevent medial cortex penetration (Fig. 17). Individualized treatment is recommended. Other surgical treatments have been described, including percutaneous pinning,50 tension band wiring,51 and external fixation.52 Medullary curettage and bone grafting is used for nonunion,23,36 which can be done with plate fixation or even in conjunction with intramedullary screw fixation (Fig. 18). Fig. 17. (A, B) Intramedullary screw fixation of a Jones fracture. There is engagement of the dorsal cortex because of the curvature of the bone in the sagittal plane and the engage- ment of the medial cortex because of the curvature of the bone in the transverse plane. 618 Buddecke et al Fig. 18. (A) Nonunion of the fifth metatarsal as indicated by obliteration of the medullary canal. (B) Fifth metatarsal nonunion after medullary curettage, bone grafting, and intrame- dullary screw fixation. (C) Radiograph demonstrating complete healing of the previous nonunion site. Other than the difficult healing potential of these fractures, complications are not common. One of the most common complications after intramedullary screw fixation of fifth metatarsals is hardware irritation from the screw head. The head of the screw can irritate the sural nerve, or the incision and scarring can lead to sural nerve compli- cations. Other complications that are encountered are generally a direct result of the surgical technique, including improper placement of the screw, such as penetration of the medial cortex, or use of incorrect screw size. The technique for intramedullary screw fixation includes making an incision prox- imal to the styloid process. If medullary curettage and bone grafting is needed, this incision can be lengthened. Otherwise, a small stab incision is made. The patient is positioned in a lateral decubital position with adequate room for fluoroscopy. The alignment of the guidewire can be assessed with fluoroscopy, and appropriate mapping performed. Ideally, the guidewire enters the styloid process slightly higher and slightly medial to the tip of the bone. The guidewire is then advanced down the medullary canal and assessed with fluoroscopy in various planes. It should be ensured that the guidewire is down the canal and does not exit any cortex. Once the guidewire placement is confirmed, the proximal cortex can be drilled and appropriate-length screw placed. Again, fluoroscopy is used to critically assess the position of fixation. In contrast to junctional fractures of the fifth metatarsal, avulsion fractures of the styloid process have a good tendency to heal. Avulsion fractures are located in meta- physeal bone and are proximal to the mechanical forces that subject the junctional fracture to motion. Avulsion fractures are caused by an inversion type of injury, leading to pull of the peroneus brevis tendon and avulsion of the styloid process. A slip of the lateral band of the plantar fascia has also been implicated in causing avulsion frac- ture.22 It was thought that the insertion site of the peroneus brevis was too expansile  Metatarsal Fractures 619 to cause many of the avulsion fractures that occur just at the tip of the styloid process. However, nondisplaced and minimally displaced fractures are successfully treated with immobilization in a weight-bearing CAM boot. When displacement occurs, open reduction with internal fixation or percutaneous fixa- tion is recommended. Fractures involving a small portion of the styloid process can be excised. The insertion site of the peroneus brevis is usually expansive enough that tendon anchoring is not necessary. However, larger fractures that are excised may mandate reattachment of the brevis tendon (Fig. 19). Fractures with more than 2 mm of displace- ment or those involving 30% or more of the joint should be considered for surgical inter- vention.53,54 One of the more common methods of fixation includes intramedullary screw fixation as previously described for Jones fracture fixation. Similar to intramedullary screw fixation for Jones fractures, there is disagreement in the size of screw that is rec- ommended. However, the technique is the same for fixation of this fracture pattern. Choosing the appropriate screw size and making sure to overdrill the fracture fragment prior to screw placement are important steps to prevent fracturing this fragment. Addi- tional discussion of fixation of this fracture has been with regard to true intramedullary fixation versus fixation that engages the medial cortex (bicortical fixation) of the fifth metatarsal55 and comparison of tension band fixation with bicortical screw fixation.56 Morshirfar and colleagues55 performed a cadaveric study comparing standard intrame- dullary screw fixation with lag screw fixation by engaging the medial cortex of the fifth metatarsal. They demonstrated a significantly greater load to failure in the lag screw tech- nique than in the intramedullary screw technique. Caution should be taken with place- ment of screws across these avulsion fractures. Fracture of the fragment can occur, especially with larger screws and smaller fragments. Tension band fixation is also a common option for fixation of these fractures. This approach affords solid fixation with smaller pins in place of larger-diameter screws and risking fracture of the fragment. Fig. 19. Radiograph showing reattachment of the peroneus brevis tendon with soft tissue anchor after excision of the avulsion fracture of fifth metatarsal. 620 Buddecke et al Fractures of the fifth metatarsal shaft are commonly encountered. The typical frac- ture pattern is spiral and may have a butterfly fragment or further comminution. Eval- uation should be directed toward the amount of displacement and any angulation or shortening. Although disruption in length or position of the fifth metatarsal head is more easily tolerable than that of the other metatarsals, the goal should be to maintain as normal a metatarsal parabola as possible. Conservative treatment is often successful and includes initial immobilization and non–weight bearing for 4 to 5 weeks followed by protected weight bearing in a fracture boot for an additional 4 weeks. Surgical intervention should be implemented when displacement is greater than 3 to 4 mm, when angulation is greater than 10 ,54 or if extensive shortening is noted. Fixation can be accomplished with interfragmentary screw fixation or plate fixation. Caution is warranted if interfragmentary fixation is planned. Often, there is a butterfly fragment, making stability difficult. In addition, the shaft of this bone can be relatively fragile, and interfragmentary fixation can cause further comminution. Consequently, the authors typically use plate fixation for many of these fifth metatarsal shaft fractures (Fig. 20). Fig. 20. (A–C) Comminuted fifth metatarsal shaft fracture with subsequent realignment and stabilization with locking plate construct.  Metatarsal Fractures 621 The final fracture location noted within the fifth metatarsal is the neck fracture. This fracture is often relatively nondisplaced and amenable to healing with weight-bearing ambulation in a fracture boot. In cases with significant displacement, fixation is neces- sary. Similar to the techniques previously described, fixation can be done with percu- taneous pinning or open reduction with pinning. Less commonly, plate fixation can be performed. As with all fractures, delayed union, nonunion, and malunion are always possible when the integrity of the osseous segment has been disrupted. Delayed unions and nonunions lead to extended time away from activity and temporary change in lifestyle, which may lead to the need for surgical intervention or revision surgery. Malunion can cause transfer metatarsalgia and any other problem associated with metatarsal parabola disruption. A less common issue noted with metatarsal fractures is arthritis. Most metatarsal fractures do not involve articulations. However, arthritis is a problem that the physician needs to be aware of with fractures involving the base or head of these bones. Other complications can include those involving nerve structures around the fore- foot. The issues with the sural nerve can be encountered with surgical intervention of any fifth metatarsal fracture. These issues are typically noted with incisions placed in the area of the nerve or with screw head irritation with intramedullary screw place- ment. Other superficial nerve issues can be encountered with surgical approaches to the other metatarsals. The branches from the cutaneous nerves are always at risk with dorsal incision placement in the forefoot. In addition, there is not a lot of soft tissue coverage in this area, making injury or entrapment a possible complication. Surgical technique becomes extremely important in this situation. Prevention of the problem is typically easier than later treatment of the complication. SUMMARY Metatarsal fractures can present with a variety of situations. Ranging from the rela- tively benign, isolated central metatarsal fracture to the crush injury leading to exten- sive damage of the soft tissue and osseous component, these fractures can cause a significant inconvenience to the patient. With the exception of the fifth metatarsal fractures, little standardization is available for the treatment of metatarsal fractures. Controversy still exists regarding to the proper treatment of various patient popula- tions for junctional fifth metatarsal fractures. Consequently, the foot and ankle physi- cian must understand the various attitudes that each fracture exhibits. The importance of the first metatarsal with regard to overall foot function makes anatomic alignment paramount. Attention to detail can help prevent long-term sequelae. Central metatarsal fractures have a high chance of union, with little known about extensive complications. However, disruption in the metatarsal parabola can cause undue discomfort. 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