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Point-Counterpoint: Central Metatarsal Fractures: Cut Or Cast?
Cut.
When it comes to central metatarsal fractures, this author says surgical correction, when appropriately indicated, can stabilize the fractures and prevent complications in the long term.
By Joshua J. Mann, DPM, FACFAS
Metatarsal fractures are among the most common traumatic injuries of the foot and will often cause prolonged disability if physicians initially overlook or mistreat them. Petrisor and colleagues found that fractures of the metatarsals occurred most often in the second to fifth decades of life, and with increasing frequency from the first metatarsal (1.5 percent) and central metatarsals (10 percent) to the fifth metatarsal (68 percent) in their retrospective study.1 The rest of the available research pertaining to metatarsal fracture treatment is in line with this injury frequency.
There are numerous articles pertaining to the treatment of fifth metatarsal fractures but not as many in regard to the first metatarsal or central metatarsals. Injuries to the second, third and fourth metatarsals are not the same as those of the fifth metatarsal due to differences in anatomy and mobility.
When treating metatarsal fractures, the primary goal is to help the patient regain full function of the injured foot without the development of long-term complications. Surgeons can achieve this by restoring alignment and preserving the longitudinal and transverse arches of the forefoot, thereby maintaining the normal weightbearing distribution throughout all the metatarsals and forefoot.2
One needs to apply a clear understanding of the mechanism of injury, anatomy and principles of closed and open reduction to treat this condition successfully. Failure to do so will lead to the patient dealing with long-term difficulties secondary to abnormal weight distribution. This can lead to metatarsalgia, intractable plantar keratosis or transfer lesions, possible nerve irritation or neuroma development and longstanding deformities.3
Anatomically, the central metatarsals are very stable due to the series of ligaments at their bases (dorsal, interosseous and plantar), intrinsic muscular attachments and the thick transverse intermetatarsal ligament, which indirectly connects the central metatarsals distally by joining the plantar plates of the adjacent metatarsophalangeal joints (MPJs). Each lesser metatarsal head provides one contact point during weightbearing and it is important to maintain this distribution when treating central metatarsal fractures. There is increasing range of motion through the second to fifth tarsometatarsal joints to allow for adaptability of uneven surfaces by the metatarsal heads. Metatarsal fractures are generally divided by their anatomical location into proximal metaphyseal, diaphyseal, cervical (neck) and cephalic (head) fractures. When proximal fractures are present, it is also essential to rule out any Lisfranc joint involvement.
Acute metatarsal fractures are the result of either direct or indirect forces, and can occur from low or high-impact trauma. Direct forces often lead to transverse or comminuted fractures. Indirect twisting forces can apply torque to the foot and often produce oblique or spiral fractures. Heavy falling objects can apply direct force, which leads to various fracture types, and high-impact accidents can cause significant soft tissue damage and open fractures.
Pertinent Considerations In Treating Central Metatarsal Fractures
When treating any foot and ankle condition, I always attempt to utilize evidence-based medicine and consider what will provide my patients the best long-term outcome. Unfortunately, there is limited data for central metatarsal fracture treatment and we have to depend on expert opinion, personal experience, and review articles or case studies for guidance. Absolute indications for surgery would be open and articular fractures, and authors have stated that non-displaced or minimally displaced single central metatarsal fractures rarely require operative treatment.4
The most often mentioned guideline is performing reduction with surgical treatment in any fracture displaying more than 10 degrees of deviation in the sagittal plane or greater than 3 to 4 mm of translation in any plane.5 However, there is no biomechanical or clinical evidence that supports these recommendations. In fact, Cakir and coworkers reported that a displacement of greater than 2 mm in any direction with central metatarsal fractures was associated with a generally poorer outcome.4
Multiple metatarsal fractures are often unstable because the adjacent soft tissue structures will accentuate any deformity present. Displaced metatarsal neck fractures often angulate plantarly as a resulting action of the flexor tendons and oblique fractures of the shaft tend to shorten with the pull of intrinsic muscles.2,6 Due to these reasons and the aforementioned guidelines, if there is any appreciable deviation in the metatarsal head position or shortening of the metatarsal(s) when fractured, one should address fractures with closed or open reduction, and maintain the repair with surgical fixation.
Key Insights On Surgical Techniques For Central Metatarsal Fractures
To date, there are only review articles and expert opinions that discuss the surgical treatment of central metatarsals, and no studies report union rate or time to union for central metatarsal fractures.2 For simple fractures of the central metatarsals, retrograde percutaneous pinning with a Kirschner wire is the treatment of choice.6 The most common technique described in the literature relies on driving the Kirschner wire in a retrograde manner, capturing the base of the proximal phalanx laterally and directing it medially through the distal and proximal metatarsal fracture fragments to offset the tendency of these to drift laterally and plantarly.2
If percutaneous stabilization is unsuccessful, then open reduction will be required. I recommend dorsal longitudinal incisions centered over the affected shaft. First insert a wire in an antegrade manner through the fracture into the distal fragment and then drive the wire in a retrograde direction to capture the proximal fragment. Utilize this approach when one cannot achieve closed reduction or if excessive dorsal displacement of the distal metatarsal fragment occurs.7
Alternatively, metatarsal head, comminuted, oblique or spiral fractures of the central metatarsals may require screw and plate fixation for adequate reduction. Prior to performing an open reduction with internal fixation, one should assess the soft tissue envelope needs and rule out compartment syndrome. External fixation is sometimes necessary if soft tissue swelling is extensive.
I recommend utilization of intraoperative fluoroscopy to assess for adequate reduction of the fractures and proper placement of fixation. One can assess metatarsal length, rotation and declination with anteroposterior, medial oblique, lateral and tangential views.
In Summary
There is debate in regard to the best treatment of central metatarsal fractures. Several factors to consider are the number of metatarsals involved, whether it is an open or closed fracture, and the amount of soft tissue damage present. Single, non-displaced or minimally displaced central metatarsal fractures tend to heal well without surgical intervention. General guidelines recommend that one perform surgery for central metatarsal fractures if there is more than 10 degrees of deviation in the sagittal plane or greater than 3 to 4 mm of translation in any plane.5 However, no available biomechanical or clinical evidence supports these recommendations.
Multiple central fractures will generally displace as a unit due to their soft tissue attachments and one often needs to address these fractures surgically. The key is to re-establish the metatarsal length, rotation and declination. Addressing central metatarsal fractures surgically will help provide adequate stabilization of the fractures and decrease the chances of lost reduction and the development of long-term sequelae. Podiatrists commonly deal with central metatarsal fractures and there would be great benefit from long-term prospective studies determining the time to union, union rate and return to work and activity.
Dr. Mann is a Diplomate of the American Board of Foot and Ankle Surgery. He is the Director of the Dekalb Medical Center Podiatric Residency Program in Decatur, Ga.
References
1. Petrisor BA, Ekrol I, Court-Brown C. The epidemiology of metatarsal fractures. Foot Ankle Int. 2006; 27(3):172-4.
2. Boutefnouchet T, Budair B, Backshayesh P, Ali SA. Metatarsal fractures: A review and current concepts. Foot Ankle Int. 2014; 16(3):147-63.
3. Alepuz ES, Carsi VV, Alcantara P, Llabres AJ. Fractures of the central metatarsal. Foot Ankle Int. 1996; 17(4):200-03
4. Cakir H, Van Vliet-Koppert St, Van Lieshout EM, et al. Demographics and outcome of metatarsal fractures. Arch Orthop Trauma Surg. 2011; 131(2):241-45.
5. Shereff M. Fractures of the metatarsals. Orthopedics. 1990; 13(8):875-82.
6. Rammelt S, Heineck J, Zwipp H. Metatarsal fractures. Injury. 2004; 35(Suppl 2):S-B77-86.
7. Heim U, Pfeiffer KM. Periphere Osteosynthesen. Springer-Verlag, Berlin, 1988, p. 340.
Cast.
Noting conservative treatments are comparable to surgical treatments for central metatarsal fractures, this author says one can treat most fractures with casting and other non-operative modalities.
By Marc Jones, DPM, FACFAOM
Central metatarsal fractures are common and research has shown that they account for approximately 30 percent of all foot fractures.1 The third metatarsal is most frequently affected and the fourth is the least frequently affected.2 Although there has been much research on the treatment of fifth metatarsal fractures, there is less published regarding central metatarsal fractures with even less comparing surgical versus conservative treatment.
In general, one can treat most metatarsal fractures conservatively with casting, walking boots or even surgical shoes in some cases due to the fractures being simple, closed and minimally displaced.3,4 Conservative treatment is successful in part due to the relative lack of motion, soft tissue attachments and stable proximal articulations of the metatarsals.3 For more complex and displaced fractures, additional methods of treatment beyond casting, including extracorporeal shockwave treatment (ESWT) and low-intensity pulsed ultrasound (LIPUS), can enable practitioners to increase the number of patients they treat conservatively and decrease those needing to have surgery.
Accepted guidelines suggest that more than 10 degrees of angulation in the sagittal plane or 3 to 4 mm of displacement are indications for surgical treatment of central metatarsal fractures.5 These guidelines are not universally accepted as some sources delineate that surgical correction is indicated only when there is greater than 20 degrees of angulation in the sagittal plane or the fracture is displaced and translated more than 50 percent of the metatarsal width.6,7 Patients generally will tolerate significant displacement in the frontal and transverse plane in the long term without anatomical or surgical reduction.3
Research continues to show that conservative treatment methods can extend the aforementioned guidelines to treat a greater number of central metatarsal fractures conservatively. In rare cases when open fractures and compartment syndrome are present, surgical treatment is indicated, and one should not treat these fractures conservatively.8
A Closer Look At Potential Issues With Surgical Treatment
The surgical treatment of metatarsal fractures is most common with K-wire fixation, either percutaneous or through an open surgical approach.9 Whether one does this as an open procedure or performs the procedure percutaneously, the complications of these surgical techniques can include pin tract infection, nonunion, delayed union, surgical site infection, hardware irritation or breakage, and metatarsophalangeal joint (MPJ) stiffness. Even when no complications are present, surgeons do not permit early joint range of motion (ROM) or weightbearing while the K-wires are in place as the K-wires are generally protruding out the plantar aspect of the MPJs.4 This leads to a challenging recovery for the patients and practitioner alike.
When one utilizes screws and plates in surgical treatment, extensive dissection and stripping of the periosteum of the metatarsal shaft can significantly increase the risk of delayed union or nonunion.4 The additional issues of irritation of the hardware and the need for hardware removal are other complications that the surgeon and patient may have to endure. Research has shown that 30 percent of patients have hardware irritation when surgeons utilize screws and plates for metatarsal fixation.7
Conservative treatment can start from day one. With this approach, one does not have to wait for edema to subside to an acceptable level prior to surgical treatment or risk morbidity or mortality due to the patient having anesthesia and surgery. In many instances, one can treat these fractures with weightbearing in a protected cast boot right away, reducing the challenges associated with non-weightbearing.
What The Literature Reveals About Conservative Treatments
Sánchez-Alepuz and Carsi compared the surgical and conservative treatment of central metatarsal fractures with a five-year follow-up.2 Out of 57 patients with central metatarsal fractures, 21 had surgical treatment and 36 had conservative treatment. The outcomes revealed no statistically significant difference between those treated conservatively and those treated surgically, even in cases of severe comminution or displacement.
Úbeda Pérez de Heredia and Martinez de Renobales evaluated treatment of 276 patients with either single or multiple metatarsal fractures, including both displaced and non-displaced fractures.10 They assessed long-term outcomes of these fractures with conservative treatment. The authors compared those patients who had early weightbearing (within first 21 days after the fracture) and those with non-weightbearing for at least the first three weeks. American Orthopaedic Foot and Ankle Society (AOFAS) outcome scores were excellent for both groups and there were very few complications. However, the authors found patients did better when they were weightbearing within the first three weeks.
In the unfortunate instance when metatarsal fractures go on to delayed unions or nonunions, surgical intervention is not a forgone conclusion. Researchers have shown ESWT to be an effective treatment for those with metatarsal fractures. Alvarez and coworkers showed an overall 90 percent success rate for ESWT in healing patients with nonunions or delayed unions of proximal metatarsal fractures.11 The authors utilized one session of ESWT and had a 76 percent success rate at the six-week mark. They reported a 90 percent success rate at the 12-month follow-up. The only significant complication was edema, which occurred in 15 percent of the patients.
Low-intensity pulsed ultrasound is another conservative treatment modality that is reportedly effective in the treatment of nonunions, delayed unions and even fresh fractures in high-risk patients.
Nolte and colleagues evaluated the treatment of 594 metatarsal fractures including 368 fresh fractures and 226 delayed unions and non-unions.12 Although a majority of the fractures were simple closed fractures (63.5 percent), other fracture types included comminuted, spiral, transverse and stress fractures. The 594 fractures all had conservative treatment with low-intensity pulsed ultrasound and the authors compared those patients with the Truven database of metatarsal fractures that had surgical treatment. Patients treated conservatively were more likely to be overweight, obese or morbidity obese, and were more likely to be men and smoke in comparison to the surgical patients.
The healing rate for fresh fractures treated conservatively was 98.1 percent in comparison to 95.4 percent of those surgically treated at one year after treatment.12 Patients who had conservative treatment for nonunions and delayed unions had a 96.0 percent healing rate while the surgically treated group had a 93.8 percent healing rate. The study showed conservative treatment with low-intensity pulsed ultrasound is equal to or better than surgical treatment even when treating high-risk patients.
When it comes to pediatric patients, studies have shown that one can utilize conservative treatment in even more extreme injury situations than in the adult population. Mahan and colleagues looked at 98 patients with multiple metatarsal fractures and found that with less than 75 percent displacement of the metatarsals, all healed uneventfully with conservative treatment. The authors showed that those with 10 percent displacement still healed uneventfully in greater than 50 percent of the cases without surgical treatment. In cases involving extensive displacement, the combination of closed reduction and casting can be a very effective treatment approach. The authors recommended that surgical treatment is not indicated when displacement is less than 75 percent and surgery is only absolutely indicated in cases of open fracture and compartment syndrome.8
In Conclusion
Since most central metatarsal fractures are simple with minimal displacement, one can treat them conservatively much of the time. One should only consider surgery when significant displacement or comminution is present. When utilizing additional treatment modalities beyond casting, surgical intervention is rarely warranted. Recent literature has shown that low-intensity pulsed ultrasound and ESWT are equivalent or superior for healing fresh fractures as well as nonunions and delayed unions. When dealing with the pediatric population, patients can tolerate greater displacement and closed reduction is a viable option for conservative treatment of these fractures. Conservative treatment additionally reduces the mortality and morbidity that are associated with surgical treatment.
In limited cases involving open fractures or compartment syndrome, surgical treatment is essential. Short of these severe cases, one should utilize conservative treatment nearly all of the time in treating central metatarsal fractures as outcomes are comparable if not better than surgical treatment.
Dr. Jones is the Lead Podiatrist and Clerkship Director at Mann-Grandstaff Veterans Affairs Medical Center in Spokane, Wash. He is a Clinical Assistant Professor at the Washington University’s Elson S. Floyd College of Medicine.
References
1. Hasselman CT, Vogt MT, Stone KL, Cauley JA, Conti SF. Foot and ankle fractures in elderly white women. Incidence and risk factors. J Bone Joint Surg Am. 2003;85(5):820-824.
2. Sánchez-Alepuz E, Carsi V. Fractures of the central metatarsal. Foot Ankle Int. 1996;17(4):200-203.
3. Buddecke D, Polk M, Barp E. Metatarsal fractures. Clin Podiatr Med Surg. 2010;27(4):601-624.
4. Kim HN, Park YJ, Kim GL, Park YW. Closed antegrade intramedullary pinning for reduction and fixation of metatarsal fractures. J Foot Ankle Surg. 2012;51(4):445-449.
5. Shereff M. Complex fractures of the metatarsals. Orthopedics. 1990;13(8):875-882.
6. Armagan O, Shereff M. Injuries to the toes and metatarsals. Orthop Clin N Am. 2001;32(1):1-10.
7. Bryant T, Beck DM, Daniel JN, Pedowitz DI, Raikin SM. Union rate and rate of hardware removal following pate fixation of metatarsal shaft and neck fractures. Foot Ankle Int. 2018;39(3):326-331.
8. Mahan ST, Lierhaus AM, Spencer SA, Kasser JR. Treatment dilemma in multiple metatarsal fractures: when to operate? J Pediatr Orthop B. 2016;25(4):354-360.
9. Sanders RW, Papp S. Fractures of the midfoot and forefoot. In: Coughlin MJ, Mann RA, Saltzmann CL (eds.) Surgery of the Foot and Ankle, Eighth Edition, Mosby, Philadelphia, 2007, pp. 2216-2235.
10. Úbeda Pérez de Heredia I, Martinez de Renobales J. Measurement of the results of functional treatment of metatarsal fractures using the AOFAS scale and the duration of work incapacity. Revista Española de Cirugía Ortopédica y Traumatología (English Edition). 2012;56(2):132-139.
11. Alvarez RG, Cincere B, Channappa C, Langerman R, Schulte R, Jaakkola J, Malancon K, Sherreff M, Cross, GL. Extracorpereal shock wave treatment of non- or delayed union of proximal metatarsal fractures. Foot Ankle Int. 2001;32(8):746-754.
12. Nolte P, Anderson R, Strauss E, Wang Z, Hu L, Xu Z, Steen RG. Heal rate of metatarsal fractures: A propensity-matching study of patients treated with low-intersity pulsed ultrasound (LIPUS) vs. surgical and other treatments. Injury. 2016;47(11):2584-2590.
