Key Considerations For The Treatment Of Central Metatarsal Fractures

Often, we find ourselves plagued with the decision of whether to treat central metatarsal fractures operatively versus non-operatively. Either option may have convincing arguments but is there a more objective way to approach this decision? For the purposes of this blog, I am focusing on central metatarsal fractures and not speaking on the treatment of either first or fifth metatarsal fractures. 

Central metatarsal fractures often occur simultaneously. For example, 63 percent of third metatarsal fractures occur concurrently with second or fourth metatarsal fractures and 28 percent with both.¹ When do we shift our focus from non-operative treatment to surgical intervention in order to prevent long-term complications?  

We can all probably agree that non-displaced fractures are amenable to non-operative treatment. This includes some sort of immobilization or protected mobilization in a CAM boot or surgical shoe. However, the gray area involves how much displacement and angulation one should accept. Commonly documented acceptable levels of displacement include 10 degrees of angulation and only three or four mm of translation.^2-5 We do have to remain aware that sagittal plane displacement can transfer excessive pressure to adjacent metatarsals. Therefore, a patient may tolerate sagittal displacement less than transverse plane displacement. The goal of any surgical intervention should be maintenance of a functional forefoot, which one most likely achieves through preserving the metatarsal parabola.

If there is any soft tissue compromise or fracture blisters, then one should not make an incision through compromised skin. Instead, the surgeon should explore closed reduction versus percutaneous fixation techniques.  Although there is little to no literature to support it, I would caution readers to think about injury to the plantar metatarsophalangeal joint. With retrograde pinning of any metatarsal fracture, the surgeon typically dorsiflexes the lesser metatarsophalangeal joint and inserts a K-wire plantarly into the metatarsal intramedullary canal. I believe we need to take a closer look at the risk this may pose to the plantar structures including the plantar plate and articular cartilage to the metatarsal head. Percutaneous pinning through the plantar MPJ is inherently causing a plantar plate injury with potential for flexor tendon damage. 

Some studies describe an antegrade pinning technique, which avoids disruption of the MPJ. However, closed reduction of the fracture may be more difficult with this technique as the pinning is from a stable to an unstable fragment.⁶ Anecdotally, I notice significant MPJ stiffness and pain with this plantar approach. 

When possible, I believe that open reduction with internal fixation (ORIF) from a dorsal approach with plate fixation allows better access with a more anatomic reduction and restores the metatarsal parabola while preserving the plantar MPJ soft tissue structures.  

References

1. Petrisor B, Ekrol I, Court-Brown C. The epidemiology of metatarsal fractures. Foot Ankle Int. 2006;27(3):172–175. 

2. Hansen ST. Foot injuries. In: Browner BD, Jupiter JB, Levine AM, Trafton P, eds. Skeletal trauma. Philadelphia:WB Saunders Company;1998:2405–2438. 

3. Early J. Metatarsal fractures. In: Bucholz R, Green DP, Heckman J, Rockwood C, eds. Rockwood and Green’s fractures in adults. Philadelphia:Lippincott, Williams, & Wilkins;2001:2215. 

4. Shereff M. Complex fractures of the metatarsals. Orthopedics. 1990;13(8):875–882. 

5. Armagan O, Shereff M. Injuries to the toes and metatarsals. Orthop Clin North Am. 2001;32(1):1–10. 

6. 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.