Stepping Into Better Health

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“Fractures will have their best chance of healing if treated near the time of injury. Chronic injury of several months duration can carry with it a poorer prognosis for return to normal activity.”

By Dr. Randall Kline, DPM, FACFAS, FAPWCA, Allied Bone & Joint

The foot in slow motion

       The fifth metatarsal is a long bone that exists just proximal to the fifth toe and is a key player in the biomechanical function of your foot. Upon taking a single step, the body passes over the mid-foot, loading this metatarsal with three to nine times your body weight (depending on your speed). The attachment of the peroneus brevis muscle/tendon at this metatarsal’s base contracts to pronate—allowing your foot to conform to the surface on which you are walking. It then relaxes to allow your foot to re-supinate by the tibialis posterior muscle/tendon to restore the foot to a rigid lever.

        Additionally, the peroneus tertius is attached to the dorsal base of this metatarsal, which contributes to dorisflexing (lifting the forefoot) as you swing forward to take the next step. This metatarsal is not only load bearing, but contributes as a functional lever in all three body planes and even has its own range of motion, independent from the other four metatarsals.

Injury Options of the Fifth

        Of the many injures that can occur to this metatarsal, there are three common fractures.

  • The Jones Fracture is an injury first reported by Sir Robert Jones in 1902. In a writing style similar to Sir Arthur Conan Doyle, Dr. Jones described an injury he sustained at a military dance in which he was dancing around a “maypole.” He fractured his fifth metatarsal  roughly 3.0 cm from the proximal tip of the metatarsal’s base, also called the styloid process. The mechanism of injury is due to the body passing laterally, while the foot remains flat upon the ground (failing to supinate). This leads to a predictable break just distal to the base, at the metaphyseal-diaphyseal junction, (see illustration).

        The most remarkable quality of this fracture is its poor ability to heal without surgical intervention, due to its occurrence within the watershed area of the bone (area of poor blood supply).  Healing is possible without surgery, however literature finds prolonged healing times as well as a high propensity for re-injury.

Avulsion fracture

  • Avulsion fractures occur commonly with acute inversion, the same mechanism that sprains or fractures ankles. This opposed effort to pronate a foot fixed in supinatio can also create a fracture at the fifth metatarsal base, from the peroneus brevis tendon literally pulling the bone apart.   

        This injury is common with basketball players as the foot slides down an opponent’s leg  during a rebound. However, it can also occur simply by misstepping off of a sidewalk. Remarkably, this area of the bone has an excellent blood supply, but also has a tendinous attachment that will work against immobilization for normal healing. As such, an athlete may choose fixation of the fragment surgically in order to have a quicker return to normal activity.

  • Dancer’s fractures occur within the distal shaft of the fifth metatarsal and are called such due to their mechanism of injury. The typical biomechanics preceding this injury include a plantar flexed foot (pointing downward), with the weight of the body rolling the foot onto its lateral edge—similar to a ballet dancer landing in demi point position, but losing balance to the outside of the body. The fracture will appear as a spiral oblique configuration, which is many times quite unstable.     

        Prior to 1998, these fractures were all surgically corrected, until a study came out regarding the treatment of a New York dance company. They found that if the fracture was not displaced, the blood supply was sufficient in this area of the bone to have a chance at heal with cast immobilization. This can vary greatly however with age, health, and tobacco use and will need to be discussed thoroughly with your physician.

Bone Healing

        There are many factors contributing to bone healing including age, blood flow, underlying disease, and nutrition, such as calcium and vitamin D intake. Also, use of tobacco products can significantly occlude blood flow to the lower extremities.   

        In the presence of any fracture, tobacco use should be discontinued immediately. Also, fractures will have their best chance of healing if treated near the time of injury. Chronic injury of several months duration can carry with it a poorer prognosis for return to normal activity.

What you can do

        Prevention is of course the best line of defense. Use proper equipment and wear appropriate shoes when engaging in your favorite sports.

        As a runner, lace your shoes snugly and replace them every six months. Also, be sure to use your running shoes for running only. The rest of the time wear your other shoes—in my case, I use old, retired, running shoes—for other activities.

        That said, injury can happen to anyone. If you suspect any fracture, contact your physician immediately and seek an x-ray. You’re better off knowing and seeking immediate treatment, than walking on a fracture and displacing it, (or further displacing it). Also, a suspected or x-ray proven fracture may be one of several injuries. Clinical correlation with the remainder of the foot, ankle and lower extremity may require further work-up, such as an MRI to discern any occult soft tissue injury to ligaments, tendons, muscles or joints.

        With the outdoor running season well upon us, I wish you a healthy, active summer.

Train wisely my friends!

Dr. Randall Kline is a board-certified podiatrist specializing in injury, wound and diseases of the foot and lower leg. Contact Allied Bone and Joint at (574) 247-4667 or visit the AlliedBoneandJoint.com website for more information.

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