Bone Fractures and Healing

Clinical Situation Involving Bone Fracture

Mr. G is a 45-year-old man who enjoys motorcycle riding and is also a heavy smoker. He was involved in a motorcycle versus car accident in which he suffered an open (compound) fracture of his right tibia and fibula as well as a displaced (Colles’) fracture of his right distal radius. Mr. G required open reduction and external fixation of his right leg with pins. The right arm was reduced and immobilized in a short plaster cast. The arm cast was removed after six weeks with a good result and return to normal function after 12 weeks. Mr. G developed an infection in his right leg, required multiple surgeries and skin/muscle grafts, and still walks with a cane one year after the initial injury.

Signs and Symptoms

In an open, or compound fracture, the bone pierces the skin and is visible to the naked eye. The bones in a compound fracture are literally broken into two pieces; one or both ends protruding through the skin. These types of fractures require surgical intervention and pinning. Osteomyelitis is a risk because the bone has been exposed to the elements (Hak, Linn, Mauffrey, Hammerberg & Stahel, 2013). These fractures are extremely painful and often hard to heal due to infection and surrounding muscle and vascular tissue damage. Some athletes with closed tib-fib fractures may only feel moderate pain with these fractures and may put off seeing a doctor, not realizing the bones are fractured. A compound fracture is impossible to miss, however.

A displaced fracture is not open, but closed, and requires reduction in order to align the ends of the bones together for proper healing. The fractured extremity must then be immobilized in order for proper healing to occur. Another name for a displaced radial fracture is Colles’ fracture. These are extremely painful and require immediate medical attention. These are commonly seen when people attempt to break a fall by putting their hand down, resulting in a U-shaped deformity at the wrist because the radius is tilted upward. Even if the classic U-shape is mild, the wrist will be painful, swollen and difficult to move.

Length of time for healing. As a general rule, bone healing will take six to eight weeks for short or upper limb bones. The long bones in the lower extremities take longer to heal and usually, this is around 12 to 16 weeks. Children generally heal much more quickly than adults. Any co-morbidities or external factors, such as diabetes or smoking, will also affect the time it takes for bones to heal.

Five stages of bone healing. The stages of healing are the same as bone growth. In order to heal correctly, the edges of the broken bones must be touching. If not, they will heal incorrectly and must be re-broken and immobilized. First, a hematoma is formed when blood collects around the fracture site. In the inflammatory stage, cytokines are released from the injured tissue and begin the healing process. In stage three, fibrocartilage begins to fill the space between the broken bones and vascularization begins. Bony callus formation, or consolidation, is when bone replaces cartilage through ossification in stage four. Finally, remodeling takes place in the final stage when osteoblasts and osteoclasts remodel and fill in the damaged bone.

Factors That Impair Bone Healing

According to a study done by the University of Pennsylvania, smokers have a 15% higher risk of nonunion of the long bones, 12% higher risk of delayed healing of open fractures and a 5% higher risk of infection than do their non-smoking counterparts (Schenker, Scolaro, Baldwin, Mehta, & Ahn, 2013). Smoking interferes with the stages of healing listed above due to vasoconstriction of blood vessels and inhibition of oxygen to red blood cells. This interferes with collagen synthesis and remodeling, and as seen with Mr. G, can generally result in poor outcomes.

References

Hak, D. J., Linn, S., Mauffrey, C., Hammerberg, M., & Stahel, P. (2013). Incidence and risk factors for surgical site infection following tibial plateau fracture ORIF. Bone & Joint Journal Orthopaedic Proceedings Supplement, 95(SUPP 16), 27-27.

Schenker, M. L., Scolaro, J. A., Baldwin, S. M., Mehta, S., & Ahn, J. (2013, March). Blowing smoke: a meta-analysis of smoking on fracture healing and postoperative infection. American Academy of Orthopaedic Surgeons. Retrieved from http:www.aaos.org