5th Metatarsal Base fractures: General facts
- Usually from twisting injuries to the foot or a blow to the outside of the foot
- Some areas of the 5th metatarsal bone are predisposed to poor bone healing (nonunion) due to a poor blood supply
5th Metatarsal Base Anatomy
- Prominence at the base of the bone is called the 5th metatarsal tuberosity
- Serves as the attachment site for the peroneal tendon, which turns your foot outwards (everts)
- The base of the bone is divided into three zones (see picture at end of handout)
Nonoperative Treatment of 5th Metatarsal Base Fractures
- Use antiinflammatories, avoid strenuous activity, elevate above the level of your heart
- Ice 20 minutes at a time 2-3 times per day
- Used for well aligned fractures in zone 1
- For zone 1 fractures, you will be placed into a short walking boot for 4-6 weeks
- You may weight bear as tolerated in the boot
- Transition to shoe at 4-6 weeks
- No high impact activity until minimum 3 months
- For zone 2 fractures, you will be placed into a short walking boot for 8-10 weeks
- You may not put any weight on the foot for 6 weeks
- You may then begin putting weight on the foot in a shoe for 2-4 weeks
- Transition to a shoe at 8-10 weeks
- No high impact activity for 3-3.5 months
Operative Treatment of 5th Metatarsal Base Fractures
- Used for zone 1 fractures that don't heal with nonoperative treatment
- You are given the option for zone 2 fractures
- Benefits of surgery include quicker return to bearing weight and more reliable healing of the bone
- Encouraged for most zone 3 fractures
- Surgery typically involves a metal screw being inserted through a small incision on the outside of the foot
- The screw is placed into the inside of the 5th metatarsal bone (which is hollow)
- This compresses the fracture and helps to stabilize the fracture
- Occasionally, if the fracture needs to be fixed with plate and screws rather than a screw alone
