Metatarsal Stress Fractures

By
Rob Rinaldi,DPM
Posted March 1st, 2006

The good news is you can avoid metatarsal stress fractures with
thoughtful training, proper footwear, and controlled pathomechanics.
A stress fracture usually affects the second metatarsal, but it can happen in any of the five metatarsals in the foot. Every athlete involved in running fears this injury. The good news is you can avoid metatarsal stress fractures with thoughtful training, proper footwear, and controlled pathomechanics. Runners aren’t the only athletes who live in fear of a metatarsal stress fracture; the injury is also common in sports such as basketball, dancing, soccer, and hiking.
Anatomy/pathology
Of the five metatarsals in a normal foot, the second metatarsal is usually the longest and it has the least amount of capacity for motion. It is like a pivot point. It has little, if any, upward or downward motion (dorsiflexion and plantarflexion), and it has no side-to-side movement.
The first metatarsal, on the other hand, has a great deal of dorsiflexion and plantarflexion, primarily during the propulsive gait phase. The first metatarsal and the great toe work hard to drive the foot and leg in the gait cycle.
Mechanical pathology of the first metatarsal can cause excess stress on the second metatarsal. A slight bunion deformity, for instance, will cause increased stresses on the second metatarsal during gait phases, from midstance to toe-off. Increased or prolonged pronation causes the first metatarsal to excessively dorsiflex, adding stress to the second metatarsal. Very often, a bunion deformity and prolonged pronation occur simultaneously.
The second metatarsal becomes vulnerable when it is overloaded with either too much pronation or too little pronation. A high arched or a “pes cavus” foot type (too little pronation) will also cause increased stress on the second metatarsal, especially if it is the longest of the five metatarsals.
Metatarsal three and four are smaller in size, but their ability to move up and down gives them some resiliency and protection from stress and fracture.
The fifth metatarsal is the smallest of all and it has a great deal of motion, thus a great deal of protection from injury. Injuries sometimes do occur to the fifth, but not usually a stress fracture along the midshaft.
Stress fracture defined
Every bone in our skeletal system is covered with a thin membrane called periosteum. This tightly fitting veil covering the bone allows for a flow of blood, the passage of nutrients, and most important to this discussion, the attachment of muscle, tendons and ligaments to the bone. A stress fracture is not really a fracture, as in a broken or crushed bone, but rather a lifting of the periosteum off the bone. One of the soft tissue elements attaching to the bone becomes overworked and pulls away from its attachment and the periosteum lifts with it. Bleeding occurs behind the periosteum and intense pain occurs. Indeed, if the injury is ignored, a true fracture will occur.
Diagnosis
The athlete will usually have no indication that injury occurred at the time it happens. Pain may start afterward, while simply walking. The pain will be localized. Applying digital pressure along the shaft of the metatarsal will cause intense pain in the area of injury. Often, runners will be able to start exercising with little or no pain, but within a short time or in just a few steps the pain will intensify until they have to stop running. This intense pain dissipates rapidly when the runner stops.
An X-ray will not show any injury until healing has started and bone callus is being produced. However, a bone scan is very accurate and, unlike the x-ray, can be used early when a stress fracture is suspected.
Therefore, clinical diagnosis is very often more important than an X-ray diagnosis.
Treatment
A metatarsal stress fracture responds to rest and wearing a stiff-soled shoe. NO BAREFOOT WALKING! It is usually not necessary to use a cast, walking boot or crutches. Rest for a minimum of three to four weeks is all that is needed prior to resuming exercise programs. I recommend stationary cycling as a workout to maintain cardiovascular fitness.