Metatarsal Fractures




See Appendix for stepwise instructions for weight-bearing and non–weight-bearing short-leg casts and a lower extremity splint used in the treatment of metatarsal fractures.


See Expert Consult for the electronic version of a patient instruction sheet named “Broken Foot or Ankle,” which covers the steps of care from pain relief to rehabilitation exercises. This can be copied to hand out to patients to assist them during the treatment period.


Metatarsal fractures are relatively common, making up 5% to 6% of all fractures. To the primary care provider, they offer opportunities and pitfalls. Most are best managed conservatively, producing very good outcomes and lending themselves to primary care management. Pitfalls arise from the fact that it is easy to underestimate the severity of certain metatarsal fractures. Significant angulation may go undetected, as may considerable soft tissue injury. Relatively subtle injuries such as Lisfranc fracture dislocations and stress fractures of the proximal fifth metatarsal may be missed initially, leading to prolonged recovery or long-term disability. Avulsions of the tuberosity of the fifth metatarsal may be overlooked if the primary care provider does not recognize the mechanism of injury that produces this injury. Knowledge of metatarsal fracture patterns and their associated complications helps clinicians avoid the pitfalls and select the more easily managed fractures to treat.


Fractures of the Metatarsal Shafts


Anatomic Considerations


The first metatarsal is an important component of the arch of the foot, and it plays a key role in weight bearing. Malalignment of the first metatarsal is therefore tolerated more poorly than malalignment of other metatarsals. The dorsalis pedis artery and one of its major branches, the deep plantar artery, pass near the base of the first metatarsal ( Figure 15-1 ). Injuries to these arteries or the arcuate artery may complicate metatarsal fractures. The splinting action of adjacent metatarsals generally prevents much displacement unless fractures are multiple or near the metatarsal head. When displacement does occur, the pull of intrinsic muscles of the foot and the flexor tendons of the toes usually causes the head of the metatarsal to displace in a plantar direction (i.e., apex dorsal angulation at the fracture site). The soft tissues of the dorsum of the foot are relatively thin. When crushed against the underlying metatarsals, these tissues may necrose and subsequently slough, converting a closed fracture into an open one.




FIGURE 15-1


Anatomy of the foot, including the dorsalis pedis artery and its branches and the ligamentous attachments of the metatarsals.


Mechanism of Injury


Many shaft fractures result from a direct blow such as when a heavy object is dropped on the foot. Twisting forces may also produce these fractures. Because of the first metatarsal’s relative size and strength, considerable force is required to fracture it. Ballet dancers may fracture the distal fifth metatarsal shaft by rolling onto it while raised up on their toes or by landing on it after a jump (“dancer’s fracture”).


Clinical Presentation


Considerable pain and tenderness accompany most acute metatarsal fractures, and weight bearing is difficult or impossible. Direct pressure under the metatarsal head produces pain at the fracture site, as will axial loading (i.e., compressing the proximal phalanx or metatarsal head toward the calcaneus). Axial loading is useful in distinguishing soft tissue injury from a fracture. Both may have significant point tenderness on direct palpation, but axial loading should not produce significant pain unless a fracture is present. Diagnostic maneuvers should be performed gently to avoid displacing the fracture and to minimize patient discomfort. Because of the foot’s dependent position, swelling and ecchymosis occur quickly and may be significant, leading to early diffuse tenderness that may obscure point tenderness at the fracture site. The swelling may be severe enough to produce a compartment syndrome. The swelling associated with a fracture of the first metatarsal is especially pronounced, and the risk of a compartment syndrome is greater in these cases.


Imaging


Most metatarsal shaft fractures are either oblique or transverse, and they generally have at least a small amount of displacement ( Figure 15-2 ). In many cases, overlapping shadows on the lateral view conceal significant angulation or displacement. The oblique view may best reveal fragment positions. It is important to examine the radiographs carefully to look for apex dorsal displacement because the displaced metatarsal head can cause significant disability if its position is not corrected. When fragment position is difficult to determine with anteroposterior (AP), oblique, and lateral views, it may be beneficial to obtain a modified lateral view with the metatarsals rotated slightly to avoid some shadow overlap. With crush injuries and very high forces, multiple fractures, comminution, or both are often seen ( Figure 15-3 ).




FIGURE 15-2


A, Fracture of the fourth metatarsal, oblique view. Note slight shortening and 3 to 4 mm of displacement. B, Lateral view. Note the double-density line at the fracture site ( arrow ) and near-normal position of the fourth metatarsal head.



FIGURE 15-3


Crush injury of the foot. Note the marked widening of the space between the first and second metatarsals and displaced fractures of the second and third metatarsals, first toe, and first cuneiform. Although widening of the space between the first and second metatarsals is usually caused by Lisfranc fracture dislocations, it is attributable to the displaced first cuneiform fracture in this case.


Indications for Orthopedic Referral


Emergent Referral (Within 30 to 60 Minutes)


Patients with any open metatarsal fracture or with associated vascular compromise should be referred immediately for operative treatment.


Early Referral or Consultation (Within a Few Hours)


In some high-force injuries, the skin remains intact initially, but necroses and sloughs in the ensuing days. This may convert the injury into an open fracture and have a dismal impact on healing and outcome. Sloughing may occur even when the skin appears to have only minor damage. The provider should remain alert for this possibility and strongly consider an early consultation whenever a significant crush injury has occurred or the skin appears to be in jeopardy.


Nonemergent Referral (Within a Few Days of Injury)


Most patients with displaced fractures of the first metatarsal should be referred to an orthopedic surgeon even if the displacement appears fairly mild. Anatomic position of this bone is desirable because of its important role in weight bearing. Patients with displaced fractures of multiple metatarsals, displaced fractures that occur very close to the head, and intraarticular fractures are also best referred because these injuries usually require pin fixation. With all metatarsal fractures, the provider should be extremely suspicious of concurrent dislocation of the tarsometatarsal joint and refer the patient if this injury is suspected (see later discussion of Lisfranc dislocations).


Initial Treatment


Table 15-1 summarizes the management guidelines for metatarsal shaft fractures.



Table 15-1

Management Guidelines for Metatarsal Shaft Fractures











































































Initial Treatment
Splint type and position Nondisplaced: lower extremity splint with ankle at 90 degrees
Displaced after reduction: bivalved well-molded SLNWBC
Initial follow-up visit 3 to 5 days
If a cast is applied initially, cast check in 24 hours
Patient instruction Elevation and icing crucial in first 2 to 3 days
No weight bearing until follow-up
Explain signs of compartment syndrome
Follow-Up Care
Cast or splint type and position Nondisplaced: firm-soled shoe, cast boot or SLWC if the patient is in severe pain
Reduced: SLNWBC
Length of immobilization Nondisplaced: SLWC or boot for 3 to 4 weeks if used; firm-soled shoe for 4 to 6 weeks
Reduced: SLNWBC for 3 to 4 weeks, followed by SLWC for 3 to 4 weeks
Healing time Nondisplaced: 6 weeks
Reduced: 6 to 8 weeks
Follow-up visit interval Every 1 to 2 weeks initially to assess the need for a cast change as it loosens
Every 2 to 4 weeks after cast is removed or if a firm-soled shoe is used
Repeat radiography interval Reduced or unstable: within 7 days to check fracture position
4 to 6 weeks after injury to document healing
Patient instruction Nondisplaced: advance weight bearing as tolerated
Reduced: no weight bearing for first 3 to 4 weeks
Ankle ROM and calf stretching and strengthening after the cast has been removed
Indications for orthopedic consult High risk for skin necrosis
Open fractures
Vascular injury
Compartment syndrome
Fracture dislocation
Intraarticular fractures
Displaced, unable to reduce
Multiple metatarsal fractures

ROM, range of motion; SLNWBC, short-leg non–weight bearing cast; SLWC, short-leg walking cast.


Before initiating treatment, the provider must assess neurovascular status and the viability of the overlying skin. Swelling is likely to be significant with these fractures, and strict elevation and icing are paramount. The patient and provider must be especially vigilant for signs and symptoms of a compartment syndrome, which may develop secondary to swelling. Immediate evaluation should be sought if indicative symptoms such as disproportionate pain, pallor, or paresthesias develop. Overnight admission to monitor vascular status should be strongly considered for first metatarsal fractures and significant crush injuries.


Nondisplaced Fractures


Initial immobilization can be achieved with a lower extremity splint, and the patient should avoid weight bearing until the next visit. Follow-up should ideally occur the next day if the skin may be in jeopardy, a cast was applied, the patient’s symptoms worsen, or compliance with icing and elevation is doubtful. Otherwise, the patient may return in 3 to 5 days when decreased swelling should allow casting.


Displaced Fractures


Fractures with dorsal or plantar angulation greater than 10 degrees should be reduced or referred, as should fractures with fragments displaced more than 3 to 4 mm in this plane. Care should be taken to detect and correct rotational deformity, because rotation remodels much more poorly than other types of displacement. Uncorrected displacement or angulation in the lateral or medial plane is generally well tolerated as long as displacement is not excessive ( Figure 15-4 ). Excellent results have been obtained without reduction in a small sample of ballet dancers with displaced distal fifth metatarsal fractures. Referral or consultation with an orthopedist or podiatrist is recommended if the primary care physician is uncertain about the necessity for reduction.




FIGURE 15-4


A, Anteroposterior view of an oblique fracture of the fifth metatarsal shaft with apex medial angulation. The patient was treated without fracture reduction and placed in a hard-soled shoe. B, Six weeks later, the fracture is healing with good alignment.


The practitioner can reduce most displaced metatarsal shaft fractures with the patient under local anesthesia by placing the toes in Chinese finger traps and allowing gravity to slowly reduce the fracture. In some cases, it may be necessary to apply a light weight (2 to 5 lb) around the distal tibia, perform concurrent manual manipulation, or both to achieve the reduction. Alternatively, traction can be maintained on the appropriate toe(s) by an assistant while the operator presses the distal fragment back into position with a thumb. A highly molded, bivalved, non–weight-bearing short-leg cast should maintain most reductions, provided the fracture is neither multiple nor very near the metatarsal head. Postreduction radiographs should be obtained after casting to confirm adequate reduction. If reduction is difficult (perhaps owing to soft tissue interposition) or adequate position is not maintained after release of traction, referral for possible operative reduction is required.


Follow-up Care


Nondisplaced Fractures


Nondisplaced metatarsal shaft fractures usually heal well without cast immobilization. The patient should wear a firm-soled shoe and begin partial weight bearing as tolerated. A postoperative shoe with a wooden sole can be used if the patient does not have suitable shoes or cannot wear shoes comfortably as a result of swelling ( Figure 15-5 ). If the patient does not tolerate this type of treatment because of pain, a short-leg walking cast can be applied (well molded under the arch). Casts for metatarsal fractures often become unacceptably loose as swelling subsides. A cast check in 3 to 5 days is advisable. The cast may be discontinued 2 to 3 weeks after the injury, depending on the patient’s symptoms. After removal of the cast, the patient should be switched to a firm shoe that provides good arch support and begin progressive ankle range of motion (ROM) and calf stretching and strengthening exercises. Clinical healing is usually achieved within 6 weeks. Radiographs should be repeated within 1 week to confirm that the fracture remains nondisplaced and within 4 to 6 weeks after injury to document healing.




FIGURE 15-5


Postoperative wooden shoe used in the treatment of metatarsal shaft fractures.


Displaced Fractures after Reduction


Because casting of displaced fractures is usually done at the initial visit when further swelling is likely, the cast should be bivalved and a cast check performed the next day. The patient should not bear weight on the cast for 5 to 7 days and then should be reevaluated. Cast loosening should be checked and repeat radiographs in the cast taken to assess fracture position, followed by immobilization in a non–weight-bearing cast. If the cast has not loosened, the bivalved cast can be wrapped with additional cast material to convert the bivalved cast into a solid cast. After 2 to 3 additional weeks, the cast should be removed, radiographs obtained, and an examination performed out of the cast. The patient should be converted to a short-leg walking cast for 3 to 4 more weeks with progressive weight bearing prescribed. After discontinuing the cast, the patient can be treated as described earlier for nondisplaced fractures. If fracture position is lost during follow-up, orthopedic consultation is recommended.


Return to Work or Sports


Patients with sedentary jobs may return to work within 1 week of the fracture date, provided pain and swelling are reasonably well controlled and the patient is able to elevate the extremity much of the time. Patients may return to more active duties when weight bearing produces little or no pain as long as the duties do not expose the patient to possible foot trauma. If certain duties significantly increase the pain or swelling, these duties should be temporarily stopped. After healing has occurred (callus is present and little or no point tenderness at the fracture site exists), patients may gradually resume full regular duties. Casual athletes may cautiously start rehabilitation at this point by walking for progressively longer distances. When they can comfortably walk 1 to 2 miles without experiencing significant aching afterward, they may intersperse walking with short periods of straight running on even surfaces. The running distances may be progressively increased as tolerated. Speed work and cutting should be delayed for several weeks until stamina is regained and running modest distances is well tolerated. After speed and cutting drills are well tolerated, the patient may return to game situations. Dedicated or highly competitive athletes may wish to work with a trainer or physical therapist to begin safe resistance or cross-training activities while weight bearing is impossible and to devise a plan to return to competition as rapidly and safely as possible.


Complications


Arterial injury and compartment syndromes may occur and have dire consequences such as loss of the foot or ischemic contractures (claw foot). Osteomyelitis may complicate open fractures. Unrecognized injuries of the tarsometatarsal (Lisfranc) joint may be debilitating, producing chronic pain with weight bearing and subluxation of the metatarsals toward the sole (Lisfranc injuries are discussed in more detail later in this chapter). If the fracture heals in a position with significant plantar displacement of the distal fragment, the foot may become chronically painful and develop an intractable plantar keratosis. Malunion of the first metatarsal is also tolerated poorly. Finally, complex regional pain syndrome (CRPS) may develop after metatarsal fractures. This should be suspected when significant pain and swelling persist 2 to 3 months after injury. This condition responds best if it is recognized early and treated aggressively with physical therapy.


Pediatric Considerations


The physis of the first metatarsal is sometimes confused with a fracture because it is located proximally rather than distally like the physes of the other metatarsals ( Figure 15-6 ). If significant tenderness exists over the physis, it is wise to treat the condition as though a fracture is present and repeat radiographs in 2 weeks to definitively confirm or rule out a fracture. Torus fractures of the metatarsal are relatively common and often have little or no swelling. These may be quite subtle and may be missed unless the physician is highly suspicious whenever point tenderness is present. If a fracture is apparent, follow-up radiographs taken 2 to 3 weeks later should reveal unmistakable callus. An example of such a fracture with comparison views and follow-up radiographs is shown in Figure 15-7 .




FIGURE 15-6


Oblique view of an adolescent’s foot demonstrating a fracture. At first glance, the practitioner may confuse the physis of the first metatarsal ( small arrow ) with a fracture because this physis is located proximally but the physes of the other metatarsals are located distally. The physis in this example is normal. However, a styloid fracture of the proximal fifth metatarsal is present ( large arrow ). Note the contrast between the physis and the fracture line. The lucency of the physis takes a meandering course with smooth, rounded undulations. A rim of denser white bone also lines the lucency. The lucency of the fracture is more linear, and no increased density is seen at the margin.



FIGURE 15-7


A, Anteroposterior (AP) view of a child’s painful foot. Subtle irregularity of cortex is seen in third and fourth distal metatarsal shafts ( arrows ), but the radiograph was read as “no fracture” by the radiologist. B, AP view of the opposite foot showing smooth cortex in the area of interest. This suggests that the irregularities seen on the injured foot do indeed represent torus fractures. C, Follow-up radiograph of the injured foot 3 weeks after injury. Increased bone density, representing callus, has developed at the sites of irregularity, confirming that a fracture was indeed present.


Children are susceptible to avascular necrosis of the distal second metatarsal, a condition known as Freiberg’s disease. It is characterized by localized pain made worse by walking or running. Radiographs demonstrate sclerosis and partial collapse of the metatarsal head. Although conservative treatment is usually tried first for patients with Freiberg’s disease, referral is recommended.


In children, substantial remodeling occurs after healing of metatarsal fractures. The younger the child, the greater the correction that can be expected. Children are therefore able to tolerate greater amounts of displacement than adults. Fractures having more than 20 degrees of dorsal or plantar angulation should be reduced or referred, especially if the child is older and less remodeling can be expected. Care should be taken to detect and correct rotational deformity, because rotation remodels much more poorly than other types of displacement.


Although adults with metatarsal shaft fractures may not need casting, short-leg walking casts are generally preferred in children. They offer greater protection and better initial control of symptoms than other treatment approaches. Care should be taken to maintain the foot in 90 degrees of flexion while the cast is being applied. If the cast is placed while the foot is plantarflexed and the foot lifted to 90 degrees as the cast hardens, kinking of the cast will occur. This creates pressure over the anterior ankle that can impair circulation to the foot, which can create a situation analogous to a compartment syndrome, particularly in children.


Healing is more rapid than in adults, occurring in as little as 3 weeks in young children and 5 to 6 weeks in older children. Complications are similar to those described previously for adults with two notable exceptions: malunion is less common because of remodeling, and future growth abnormalities may arise if the physis is injured. Children with any displaced physis fracture should be referred, as should children with Salter-Harris types III, IV, and V and those with conditions already indicated for referral. Primary care physicians with additional expertise often manage selected nondisplaced type I and II fractures. Care of these fractures should include confirmation of fragment position after cast application, discussion of the possibility of future growth abnormalities with the patient and parents, and follow-up radiographs at approximately 6-month intervals for 1 to 2 years to detect growth problems early and refer the child for treatment if they should develop.




Stress Fractures of the Metatarsal Shafts


The metatarsal shafts are common sites of stress fractures. Any metatarsal may be involved, with the second metatarsal most often affected. Stress fractures of the proximal fifth metatarsal, which are discussed later in this chapter, have distinct considerations and a much worse prognosis. Stress fractures usually occur several weeks after an abrupt increase in activity. Metatarsal stress fractures are commonly called “march fractures” because they often occur in military recruits during basic training. These fractures also occur in athletes who have recently changed their exercise routine or who chronically overload the bone.


Symptoms related to a stress fracture have an insidious onset. Early on, only minor pain and tenderness may be present. If activities are not limited, symptoms worsen and eventually progress to swelling, point tenderness, and severe pain with weight bearing. Symptoms precede radiographic findings by approximately 2 to 3 weeks. The first radiographic sign may be a narrowing of the medullary canal, a faint lucency, or periosteal thickening ( Figure 15-8, A ). Callus usually is present by 4 to 5 weeks ( Figure 15-8, B ), and complete healing may take months ( Figure 15-8, C ). Although bone scans and magnetic resonance imaging (MRI) can detect stress fractures soon after symptoms develop, they are often not necessary. Presumptive treatment can be started based on history and examination alone. If early diagnostic confirmation is desired, MRI is generally preferred over a bone scan. It offers greater specificity with similar sensitivity.


Mar 11, 2019 | Posted by in CRITICAL CARE | Comments Off on Metatarsal Fractures
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