Jones Fractures
Fractues in the foot especially, of the metatarsals, are very common. They account for about 7% of all fractures in the body. Of the 5 metatarsals in the foot the 5th is the most common one to suffer fractures, as much as 56% in some studies.
Jones fractures are a particular type of 5th metatarsal fractures that happen at a region of the metatarsal bone called the metaphyseal diaphyseal junction. This area is about 1.5 cm from the proximal tip of the bone which is about midway down the side of the foot. Jones fracture were first describe by Dr Robert Jones in 1902. He initially diagnosed these in four patients with one being himself. He suffered his injury after a night of dancing.
The Jones fracture is of significant importance for a few reasons. The first being their reputation for poor healing. The second is the risk of refracture when they do heal if not properly treated.
So why do they not heal?
The main reason for this is simply the anatomy. There is a tendon that attaches to the base of the bone that pulls on the fracture fragments and disrupts the healing process.
The second reason has to do with the blood flow to this region of the bone, the vessels are small, delicate, and few. This leads to poor perfusion of the fracture which slows healing.
Who is at risk?
This injury is most often seen in young male athletes and post menopausal women.
How does the injury occur?
Athletes see this injury when making a hard cut that places excess force to the outside of the foot or a fall that places weight to the outside of the foot.
In women with poor bone quality due to conditions such as osteoporosis, even mild loading to the outside of the foot can lead to a fracture.
How is this injury diagnosed?
A history and physical exam are usually all that is needed to make the diagnosis. Patients often relate feeling a "pop" or "crack" that leads to immediate pain to the outside of the foot. This is often followed by swelling, bruising to the area, and the inability to bear weight to the foot.
This is usually followed with confirmatory x-rays.
How do we treat this injury?
The treatment can be separated into two main categories, conservative and surgical.
Conservative treatment usually consist of a splint followed by cast or boot immobilization for 6-8 weeks. The benefit is not having to undergo an invasive procedure but the risk is slow or even a failure of healing. Slow healing is know as a delayed union which can range from 7.4 -47 weeks. The absence of healing is known as a nonunion and the published rate ranges between 24-33%. In the case of nonunion surgery is usually necessary which includes open reduction with internal fixation with bone graft. Another complication is refracture of the injury which happens about 3% of the time. This can occur between 3.5 and 12 months after return to activity.
(Nonunion)
Surgery's benefits include quicker healing which equates to faster return to activity, higher union rates, and lower risk of refracture. Union rates range between 94-95% when treated primarily. The technique most often used is intramedullary screw fixation which can be preformed with a single screw through a small incision. Complications include painful hardware necessitating removal, infection, and nerve injury which occur 7.75%, 1.7%, and 0.8% respectively.
After surgery a period of non weightbearing in a cast or boot followed by protected weightbearing and then physical therapy.
Return to activity can range from 4-11 weeks depending on several factors including type of activity, age, bone quality, and other comorbidities.
What treatment course it right for you, depends on may factors that should be carefully discussed between you and your foot and ankle surgeon.
