Essential Insights On Treating Fifth Metatarsal Fractures

Author(s): 
By Nicholas Romansky, DPM, and Todd Becker, DPM

Podiatric physicians commonly see fifth metatarsal fractures when treating active patients. The actual rate of occurrence is unknown but some estimate the rate at somewhere between 0.7 and 1.9 percent of all foot fractures. Fractures of the fifth metatarsal can occur at a number of locations and while some of these respond well to conservative treatment, other fractures have been notoriously hard to heal with high rates of nonunion and other complications. Proper classification of these fractures and a strong understanding of the mechanism of injury will help guide the podiatric physician in establishing a proper prognosis and treatment. It is also helpful to have a thorough understanding of fifth metatarsal anatomy (see “A Primer On Fifth Metatarsal Anatomy” below). How To Ensure An Appropriate Diagnosis The accurate diagnosis of fifth metatarsal fractures begins with a thorough history and physical exam. In many cases, the patient may not relate a specific traumatic event during the history portion of the exam, making the physical exam and subsequent studies imperative to an accurate diagnosis. In the acute setting, the patient may present with symptoms of localized pain on the outside or bottom of the midfoot. These symptoms can be insidious in nature or exacerbated by weightbearing. The physical exam may reveal ecchymosis, edema, point tenderness and/or pain against resistance. Radiographs are invaluable in the diagnosis. It is important to get multiple views of the affected foot, including AP, lateral and medial oblique views for proper assessment of the fracture for location, the amount of displacement, angulation and comminution. One should also obtain radiographs after the patient’s affected extremity has been immobilized for two to three weeks. Fracture healing is dependent on location of the fracture and the specific blood supply to that area of violation. Open reduction with internal fixation is generally indicated when the fracture is non-reducible and one notes residual displacement of 3 to 4 mm or 10 degrees of angulation in the sagittal plane. When these fractures go unrecognized, a painful plantar keratosis might develop anywhere along the fifth metatarsal. Cortical disruption or thickening, periosteal callus formation and the presence of intramedullary sclerosis may all be visible on X-rays. Other modalities one may employ for diagnosing fifth metatarsal fractures include CT, MRI, bone scan, ultrasound and tuning fork. The differential diagnosis for lateral foot pain should include stress fracture, apophysitis in adolescents, accessory bones (i.e., os vesalianum or os peroneum), herniated disc, neoplasm and tendonitis. A Guide To Common Fifth Metatarsal Fractures The site of the fracture, the fracture pattern and one’s understanding of the fifth metatarsal anatomy gives the podiatric physician an adequate amount of information related to the force producing the fracture. In regard to these fractures, there have been a number of classification systems to help clinicians better understand specific fracture patterns within a given region of the bone and their common outcomes. Capital fractures. Fractures to the head of the fifth metatarsal generally occur from direct impact (in the vertical direction) or trauma from projectiles. Fractures due to compression may also occur but these tend to be quite stable and only involve minor displacement. When significant displacement does occur, it tends to be in a plantar and lateral direction. One must pay careful attention with these fractures due to their intraarticular involvement and possible unwanted sequelae of arthritis and joint stiffness. These injuries may require open reduction with pinning if closed reduction fails to restore an appropriate articular surface. Another surgical option may include metatarsal head resection with conversion into an arthroplasty if one cannot reconstruct/realign the articular surface. Cervical fractures. The most common neck fracture of the fifth metatarsal is the spiral fracture. The spiral fracture tends to be displaced medially along the shearing axis of the fracture. In most cases, these fractures are caused by a torque force mediated by bending and loading the lateral aspect of the foot (i.e. rolling over on the outer border) while the foot is in a plantarflexed and inverted position. This is known as the demi-pointe position in relation to dancing. This type of fracture tends to require open reduction and internal fixation, which one may accomplish with crossed K-wires or 2.0 lag screws. Other types of fractures that can occur along the metatarsal neck include flexural transverse fractures and buckling impaction fractures. Most have acceptable alignment and heal well with four to six weeks of cast immobilization. Shaft fractures. Fractures along the shaft of the metatarsal tend to be the result of direct violence or impact. Comminuted fractures are the most common result and one may occasionally see a concurrent open wound and a segmental defect. Alternatively, indirect forces, such as a twisting fall, will result in a spiral fracture of the metatarsal shaft. In either case, in the absence of considerable displacement, both types of fractures tend to heal quite well with conservative non-weightbearing care. When ORIF is required, a one-third tubular plate with 2.7 or 3.5 screws is the recommended fixation for comminuted, displaced diaphyseal fractures. One may use bone graft as an adjunct if a severe defect is present after fixation is in place. For spiral shaft fractures with significant displacement, the surgical options include IM nail, lag screw with neutralization plate or cerclage wire. Another surgical option for shaft fractures in patients with open injuries or osteopenia is external fixation via a mini rail system. Sorting Through The Different Classifications Of Jones Fractures The classic metaphyseal-diaphyseal fracture, also known as a Jones fracture, is 1.5 cm to 3 cm distal to the tuberosity. Typically, this fracture can either be stress-induced or acute. The anatomic site of the cortical shaft to the proximal metaphyseal expansion creates an area predisposed to load failure.This fracture is typically an incomplete fracture with a wider gap on the lateral cortex. If weightbearing continues, one will see widening of the lateral cortex on a radiographic series. Many classification systems have attempted to simplify fractures to the fifth metatarsal metaphyseal-diaphyseal junction. Delee classified these fractures based on fracture pattern and acuity.3 Type I fractures are defined as acute fractures and heal well with conservative means. Type II fractures are defined as stress fractures of the proximal diaphysis and have a high propensity for nonunion that necessitate surgical intervention. Vertical or medial lateral forces cause these first two types. Type III fractures involve acute fractures of the tuberosity and will be discussed in detail below. Torg developed a classification system for proximal diaphyseal stress fractures based on radiographic findings.4 Stage I is an acute fracture with periosteal reaction, a planar-based fracture line and no medullary sclerosis. Stage II shows a similar process but medullary sclerosis and widening of the fracture line are similar to what one would see in delayed unions. Stage III shows complete obliteration of the medullary canal consistent with non-unions. In 1902, Sir Robert Jones described a transverse diaphyseal fracture that occurred approximately 1.5 to 3.0 cm distal to the tuberosity of the fifth metatarsal.5 Since that time, two different subsets have been termed Jones fractures. The first, defined by Stewart, occurs at the metaphyseal-diaphyseal junction and does not extend into the metatarsocuboid joint.6 This acute type of injury tends to occur with plantarflexion and adduction of the forefoot, most commonly as a result of landing on the outside of the foot. The second subset applies to proximal diaphyseal stress (aka acute on chronic) fractures. The prevailing thinking is that these fractures are the result of repetitive high bending stresses with an increase in activity. This injury is quite common in athletes who participate in such activities as running and soccer. According to Yu, et. al., these injuries are relatively refractory to conservative treatment and yield less than acceptable outcomes.7 Treatment for these fractures varies from six to eight weeks of non-weightbearing immobilization to primary surgical repair. For a Type I fracture with no displacement or comminution, the treatment of choice is cast immobilization for six to eight weeks. However, even with non-weightbearing immobilization, many of theses fractures will go on to nonunion after 10 or 12 weeks with rates as high as 28 percent being reported in the literature. Type II fractures also tend not to heal and many go on to non-union after the eight to 12 weeks of cast immobilization. Kavanaugh and Delee advocated percutaneous insertion of a cannulated screw, which one would place longitudinally down the intramedullary canal, as the primary treatment of choice for active patients with Type I fractures and all Type II fractures.3,8 They noted that active patients tend to have a much faster recovery from this surgery and can begin earlier weightbearing (usually within days) with cross-training. Other Insights On The Treatment Of Jones Fractures Portland, et. al., found union rates of 6.2 weeks for acute Jones fractures and 8.3 weeks for stress fractures treated with intramedullary screw fixation. In their study, all 22 of the patients achieved complete union.9 In 1999, Pietropaoli found no biomechanical difference between the use of 4.5 mm malleolar screws and 4.5 mm partially threaded cannulated screws.10 In 2001, Shah determined there is no difference in fixation rigidity based on the size of the partially threaded cannulated screw used (4.5 mm vs. 5.5 mm) and may actually increase the risk of intraoperative or postoperative fracture.11 Conversely, Kelly, et. al., found that fifth metatarsal fractures can accommodate 6.5 mm screws and that they had greater pull-out strength and greater purchase than 5.5 mm screws.12 They also found that using a large screw did not result in greater fracture stiffness but did result in a high rate of fracture with insertion. They suggest using a 6.5 mm screw but recommend using smaller screws for canals with diameters less than 5 mm. Husain and DeFronzo compared the use of intramedullary screw fixation with bicortical screw fixation.13 They found a greater resistance to load failure in the bicortical screw when they compared it to intramedullary screw fixation. However, there was also a high propensity for failure at the medial aspect of the screw’s exit through the stress riser. Other ORIF modalities include tension banding, percutaneous pinning and inlay bone grafting. Torg described the use of inlay bone grafting as the treatment of choice for stage II and III stress fractures.4 Tuberosity Fractures: What You Should Know Fractures to the styloid process occur proximal to the fourth/fifth intermetatarsal articulation and are believed to be the result of tensile mediated avulsion by the lateral cord of the plantar aponeurosis and/or peroneus brevis. Stewart classified these fractures based on their anatomic site and articular involvement.6 Type I fractures correspond to the aforementioned Jones fracture. Type II is an intraarticular fracture of the base of the metatarsal. Type III is an extraarticular fracture of the styloid process. Type IV is an intraarticular comminuted fracture of the metatarsal. Type V represents an injury to the apophysis in children. In adolescents, it important to remember that the apophysis is also the site of a secondary growth plate and may actually be apophysitis. One can easily determine this by the presence of a radiolucent line parallel to the shaft of the metatarsal. This apophysis is most common among girls aged 9 to 11 and boys aged 11 to 14. It disappears two to three years after it first appears. One must also be aware of the possibility of a possible secondary ossicle that mimics symptoms of a base fracture. It is important to obtain contralateral films to rule out an os vesalianum or os peroneum. Proximal fifth metatarsal fractures typically demonstrate minimal displacement and heal very well conservatively with a short leg cast for two weeks followed by a progressive return to shoe gear for another two to four weeks. Joint displacement greater than 5.0 mm, the presence of a lateral prominence, comminution or delayed union are all indications for ORIF with intramedullary screws, tension band wiring or fragment excision with tendon repair (if the fragment is small). In a frozen cadaveric study, Husain, et. al., compared 4.0 mm partially threaded screws to two 0.062 K-wire tension band wirings. They found the screw construct had greater strength and three times the load resistance of the tension band technique.12 Postoperative treatment includes a walking cast or Cam walker for four to six weeks postoperatively. Can You Spur An Earlier Return To Play For Athletes? In athletes, almost all fifth metatarsal fractures require surgical treatment. Given the high rates of delayed union, non-union or recurring fracture, early surgical intervention via ORIF or intramedullary fixation is strongly recommended. When pursuing these surgical options, the surgeon should ensure the patient is in a supine position on the OR table with the knee maximally flexed and the foot adducted on the surface of the OR table. This key position makes it very easy to place the guide or K-wire through the fracture site. Always aim down and inward to avoid hitting the lateral metatarsal cortex. Early surgical intervention helps avoid deconditioning of the athlete and typical prolonged bouts of immobilization. Modified activity or “relative rest” of activity can begin three days after the procedure. Both of the above options facilitate an earlier return to play for athletic patients. However, one should closely monitor these athletes as the rate of fracture recurrence can be 12 percent or higher. A Primer On Fifth Metatarsal Anatomy A thorough understanding of the anatomy is crucial to the successful treatment of fifth metatarsal fractures due to variations within the metatarsal. The fifth metatarsal is a long bone consisting of a capitum, cervical neck, diaphyseal shaft, a metaphyseal-diaphyseal junction as well as the distinctive tuberosity at the base. Researchers have shown that the narrow distal canal, thicker dorsal and plantar cortices, and lateral bowing of the metatarsal are all potential factors in fixation failure.1 Ligamentous attachment to the fifth metatarsal base includes a portion of the long plantar ligament as well as the short plantar ligament, an interosseous ligament between the fourth and fifth metatarsal bases. Ligamentous attachment also includes the medial, lateral, dorsal and plantar cuboid-fifth metatarsal ligaments. The peroneus brevis and peroneus tertius tendons also insert onto the base of the fifth metatarsal. Along the shaft of the bone is the origin of the three muscles, including the abductor digiti quinti brevis, the dorsal interosseous (which aids in interosseous stability due to its bipennate nature) and plantar interosseous muscles. While most of these muscular attachments play only a limited role in acute fractures, the peroneus brevis has been shown to be a major force in inversion injuries lending to styloid fractures. There is also a slip of the lateral plantar aponeurosis that attaches to the base of the metatarsal. The nutrient artery to the fifth metatarsal enters the shaft at the middle and proximal one-third junction, and divides into a short proximal and longer plantar branch. This network of arteries accounts for approximately 60 to 65 percent of the blood supply to the bone. The other 30 percent comes from the periosteum and 5 percent comes from the joint interface. There is an area of relative avascularity that exists at the juncture of the divergence of the proximal terminal branch of the nutrient artery and the metaphyseal arteries that lends itself to the high non-union rate of Jones fractures. This area tends to become even more avascular once a fracture has occurred due to the increase in cortical thickening and loss of medullary canal. Accordingly, proteins and nutrients necessary for bone healing cannot reach the fracture site, leading to a high rate of non-unions. It is also necessary to have a good working knowledge of the path of the sural nerve when undertaking surgical correction of proximal fifth metatarsal fractures. In 1999, Donley demonstrated through cadaveric dissection that one must give particular attention to the dorsolateral branch of the sural nerve when fixating these fractures due to its proximity to the insertion site of the screw.2 In Conclusion Podiatric physicians commonly see fractures of the fifth metatarsal when treating active patients. Choosing between conservative and surgical treatment is imperative because conservative treatment can sometimes lead to an extremely slow recovery or long-term problems. Both competitive and recreational athletes should be geared to a more rapid recovery. Accordingly, intramedullary screw fixation may be a more suitable option. In addition, long-term immobilization and rest can lead to muscle atrophy and stiffness, thus leading to a long recovery before the patient can achieve full athletic participation. In the athletic and active population, one must consider ORIF as a primary treatment option for Jones type fractures whereas cast immobilization may be more appropriate for the elderly and sedentary population. Late bone grafting may be necessary for avascular nonunions and severe comminution with autogenous grafting from the tibia or calcaneus. Fractures of the base of the fifth metatarsal may require ORIF only in the presence of articular involvement or distraction. It is also important postoperatively to consider the use of orthotics or shoe gear modifications to decrease the possibility of recurrent fracture. Some have also proposed that low-intensity ultrasound or other forms of bone stimulation may be beneficial in accelerating the healing time for delayed and non-unions but further research is still necessary in this area. Dr. Romansky is a Fellow of the American College of Foot and Ankle Surgeons and is a Diplomate of the American Board of Podiatric Surgery. He is a team physician for the United States Olympic and World Cup Men’s and Women’s soccer teams. Dr. Romansky is in private practice in Media and Phoenixville, Pa. Dr. Becker is a third-year resident at Crozer Keystone Health System in Pennsylvania. References 1. Ebraheim NA, Haman SP, Lu J, Padanilam TG, Yeasting RA. Anatomical and radiographical considerations of the fifth metatarsal. Foot Ankle International. 2000; 21:212-215. 2. Donley BG, McCollum MJ, Murphy A, Richardson G. Risk of sural nerve injury with intramedullary screw fixation of fifth metatarsal fractures: a cadaver study. Foot Ankle International. March 1999; 20(3):182-184. 3. Delee JC, Evans JP, Julian J. Stress fracture of the fifth metatarsal. Am J Sports Med. 1983; 11:349-353. 4. Torg JS. Fractures of the base of the fifth metatarsal distal to the tuberosity. Orthopedics. 1990; 13:731-737. 5. Jones R. Fractures of the base of the fifth metatarsal by indirect violence. Annals Surg. 1902; 35:697-702. 6. Stewart IM. Jones’ fractures: fractures of the base of the fifth metatarsal. Clin Orthopedics. 1960; 16:190-198. 7. Yu WD, Shapiro MS. Fractures of the fifth metatarsal. The Physician and Sports Medicine. Feb.1998; 26(2). 8. Kavanaugh JH, Brower TD, Mann RV. The Jones fracture revisited. J Bone Joint Surg. 1978; 60(A):776-782. 9. Portland G, Kelikian A, Kodros S. Acute surgical management of Jones Fractures. Foot Ankle International. Nov. 2003: 24(11) 10. Pietropaoli MP, Wnorowski DC, Werner FW, Fortino MD. Intramedullary screw fixation of Jones fractures: a biomechanical study. Foot Ankle International. September 1999; 20(9):560-563. 11. Shah SN, Knoblich GO, Lindsey DP, Kreshak J, Yerby SA, Chou LB. Intramedullary screw fixation of proximal fifth metatarsal fractures: a biomechanical study. Foot Ankle Int. 2001 Jul;22(7):581-4. 12. Kelly IP, Glisson RR, Fink C, Easley ME, Nunley JA. Intramedullary screw fixation of Jones fractures. Foot Ankle International. July 2001; 22(7):585-589. 13. Husain ZS, DeFronzo DJ. A Comparison of bicortical and intramedullary screw fixations of Jones fractures. J Foot Ankle Surg. May/June 2002; 41:146-153. Additional References 13. Brown SR, Bennett CH. Management of proximal fifth metatarsal fractures in the athlete. Sports Med. April 2005; 16(2):95-99. 14. Johnson JT, Labib SA, Fowler R. Intramedullary screw fixation of the fifth metatarsal: an anatomic study and improved technique. Foot Ankle International. April 200; 25(4):274-277. 15. Porter DA, Duncan M, Meyer S. Fifth metatarsal Jones fracture fixation with a 4.5 mm cannulated stainless steel screw in the competitive and recreational athlete. Am J Sports Med. 2005; 33(5):726-733. 16. Vogler HW, Westlin N, Mlodzienski AJ, Moller FB. Fifth metatarsal fractures: biomechanicics, classification and treatment. Clin Podiatric Med Surg. October 1995; 12(4):725-747.
 

 

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CE Exam #140 Choose the single best response to each question listed below. 1. What procedure is generally indicated for a non-reducible fracture and residual displacement of 3 to 4 mm or a sagittal plane with an angulation of 10 degrees? a) External fixation b) Arthroplasty c) Open reduction with internal fixation (ORIF) d) None of the above 2. When treating most flexural transverse fractures and buckling impaction fractures of the fifth metatarsal, how long should one utilize cast immobilization? a) Two to three weeks b) Four to six weeks c) Four to eight weeks d) Six to eight weeks 3. Spiral fractures … a) are the most common neck fracture of the fifth metatarsal b) may require metatarsal head resection with conversion into an arthroplasty if one cannot reconstruct the articular surface c) tend to be displaced plantarly along the shearing axis of the fracture d) all of the above 4. Capital fractures due to compression … a) tend to involve significant displacement b) are frequently caused by the demi pointe position related to dancing c) tend to be quite stable and only involve minor displacement d) a and b 5. Which type of Jones fracture is common in runners or soccer players? a) Cervical fractures b) Capital fractures c) Proximal diaphyseal stress fractures d) Metaphyseal-diaphyseal fractures 6. Husain and DeFronzo found less resistance to load failure with … a) bicortical screw fixation b) ORIF c) percutaneous pinning d) intramedullary screw fixation 7. In a tuberosity fracture, joint displacement of more than __ is one indication for ORIF with intramedullary screws, tension band wiring or fragment excision with tendon repair. a) 2.5 mm b) 3 mm c) 4 mm d) 5 mm 8. Proximal fifth metatarsal fractures typically demonstrate … a) severe displacement b) minimal displacement and heal well with four weeks of orthotic use c) minimal displacement and heal well with two weeks of a short leg cast and a progressive return to shoe gear d) severe displacement that can only be corrected with ORIF 9. According to Stewart’s classification, a Type III tuberosity fracture is … a) an extraarticular fracture of the styloid process b) an intraarticular fracture of the base of the metatarsal c) an intraarticular comminuted fracture of the metatarsal base d) an extraarticular fracture of the base of the metatarsal 10. Which of the following provides 30 percent of the blood supply to the bone of the fifth metatarsal? a) The network of arteries to the fifth metatarsal b) The plantar branch of the nutrient artery c) The joint interface d) The periosteum Instructions for Submitting Exams Fill out the enclosed card that appears on the following page or fax the form to NACCME at (610) 560-0502. Within 60 days, you will be advised that you have passed or failed the exam. A score of 70 percent or above will comprise a passing grade. A certificate will be awarded to participants who successfully complete the exam. Responses will be accepted up to 12 months from the publication date.

 

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