A bone fracture, which is simply a crack or a complete break in the bone, demands immediate medical attention to prevent severe, permanent consequences. While the body begins the healing process immediately, an untreated broken bone lacks the necessary support or alignment for this process to succeed. Ignoring a fracture allows the bone to heal in a compromised position or fail to heal entirely, leading to long-term chronic pain, disability, and impaired function. Without professional intervention to stabilize and align the segments, the resulting damaged structure complicates function and mobility.
How the Body Attempts to Repair Itself
The body’s response to a broken bone initiates almost immediately through a complex, coordinated repair process. The first phase is the inflammatory stage, where torn blood vessels bleed and form a clot called a hematoma at the injury site. This clot acts as a temporary framework, attracting specialized inflammatory cells that clear debris and release growth factors to jumpstart healing.
Following this initial response, the reparative phase begins with the formation of a soft callus, a temporary scaffold of cartilage and connective tissue. Specialized cells differentiate into chondroblasts and osteoblasts, bridging the gap between the broken bone ends with this fibrocartilaginous network. This soft callus offers temporary stabilization, but it is easily deformed without external support. Stability and correct alignment are required for the process to progress successfully.
Failure to Fuse: Nonunion and Malunion
When a fractured bone is left untreated, the two most common structural complications are nonunion and malunion. Both result from the lack of proper immobilization and alignment needed to guide the natural healing process. These failures lead to chronic pain and significant functional limitations.
Nonunion occurs when the bone fails to heal completely, leaving the fracture ends unbridged by solid bone tissue. The body may attempt to stabilize the gap with fibrous tissue, sometimes forming a false joint known as a pseudarthrosis. This condition results in persistent instability, chronic pain, and an inability to bear weight or use the limb normally, as the bone segments remain mobile.
Malunion is the result of the bone healing in an incorrect or deformed position. Without external stabilization, muscle forces and gravity cause the fracture fragments to shift, leading to the bone fusing at an abnormal angle or with rotational deformity. This improper healing causes physical deformity and can lead to permanent changes in limb length, joint function, and gait.
The altered biomechanics from a malunion severely affect surrounding joints and soft tissues. This often leads to premature arthritis in nearby joints due to uneven stress distribution. For example, a malunited leg fracture can disrupt the alignment of the ankle, knee, and hip, creating functional impairment and persistent discomfort. These structural failures often necessitate complex corrective surgery, which carries more risk than the initial treatment.
Acute Risks and Associated Complications
An unstable, untreated fracture presents immediate risks to the surrounding anatomy and the patient’s health. The sharp, mobile edges of the broken bone segments can cause extensive damage to nearby muscles, ligaments, and tendons as the limb moves. This secondary damage can result in long-term weakness and joint instability, even if the bone eventually achieves union.
A dangerous immediate complication is damage to the neurovascular structures running alongside the bone. A displaced fracture can lacerate or compress major arteries, leading to a loss of blood supply, or ischemia. Ischemia can cause tissue death and potentially require limb amputation. Nerve damage from compression or laceration can result in permanent loss of sensation or paralysis.
An open or compound fracture, where the bone breaks through the skin, introduces a severe risk of deep infection. Bacteria can infect the bone tissue itself, leading to a condition called osteomyelitis. This bone infection is difficult to treat, often requiring long-term antibiotic therapy and multiple surgical procedures. It also significantly increases the likelihood of nonunion.
A life-threatening complication that develops hours to days after the injury is acute compartment syndrome. This occurs when swelling and bleeding within the rigid muscle compartments increase pressure, cutting off blood flow to the muscles and nerves. Without emergency surgical intervention, known as a fasciotomy, the muscle and nerve tissue can die within hours, resulting in permanent functional loss.