Dear Doctors: Our 16-year-old son broke his arm skateboarding, had to have surgery, and now he’s in a cast. I broke my arm when I was a boy, but all I needed was a cast. Why does a broken arm need surgery?
Answer: Made up largely of collagen, a protein that provides a pliable framework, and calcium, a mineral that supplies strength and rigidity, bones are both hard and flexible. This allows them to withstand surprisingly high levels of force, torque and compression.
When an outside force is too great, though, a bone will break. The type and severity of break depends on the strength of that force, the angle at which it meets the bone and the health of the bone itself.
Fractures fall into two main categories — closed and open. With a closed — or simple — fracture, the bone is broken but hasn’t penetrated the muscle or skin. An open — or compound — fracture means there’s an open wound at or near the site of the break usually because the bone or bone fragments have pierced the flesh and penetrated the skin.
X-rays are used to visualize the type of break and pinpoint its location.
For a broken bone to heal properly, it must be appropriately aligned. This can require the doctor to reposition the broken ends of the bone — a procedure known as reduction. To preserve proper alignment as the bone heals, the fractured limb must be immobilized. A splint is typically used until the initial swelling common after a fracture has gone down. This can take a week or more. After that, the patient is fitted with a sling, a brace or a cast.
That your childhood fracture required only a cast suggests that the broken ends of the bone lined up easily.
In more complex cases, when a bone is broken in multiple places or in a manner that compromises its future structural integrity, surgery might be needed. This entails using screws, rods or plates to help realign, rebuild and support the bone. Recovery typically takes eight weeks for the break to heal. After, physical therapy often is needed to help regain strength and range of motion.
Dr. Eve Glazier and Dr. Elizabeth Ko are internists at UCLA Health.