The femur, commonly known as the thigh bone, is the longest and strongest bone within the human body. It connects the hip to the knee and enables nearly all forms of upright movement. Despite its strength, the femur can be broken. Because of the massive force generally required to fracture this bone, a femur break is considered a severe medical emergency. This injury often results from high-energy trauma, carrying an immediate risk of significant internal blood loss and associated complications. Immediate, professional medical attention is necessary to stabilize the patient and prevent further injury.
How Femur Fractures Occur
Breaking the femur requires a substantial amount of force, which is why these fractures are typically associated with major traumatic events. For younger, healthy individuals, the vast majority of femur shaft fractures result from high-energy trauma. Motor vehicle collisions, motorcycle accidents, and falls from significant heights are the most common mechanisms.
The location of the fracture often depends on the specific force applied. A direct impact tends to cause a transverse fracture across the bone shaft, while a twisting force can result in a spiral fracture. The femur can be broken anywhere along its length, categorized as proximal (near the hip), the shaft, or distal (near the knee).
In contrast, older adults frequently sustain femur fractures from low-energy incidents, such as a simple fall. This vulnerability is due to underlying conditions like osteoporosis, which compromises bone density and strength. Pathological fractures occur when a disease, such as a tumor, weakens the bone structure, making it susceptible to breaking under normal stress. Repetitive strain can lead to stress fractures, particularly in athletes, due to overuse.
Signs and Emergency Response
Recognizing the signs of a femur fracture is important due to the injury’s severity. The most consistent symptom is immediate, intense, and unrelenting pain in the thigh area following an accident. The person will be unable to bear any weight on the injured leg or move it normally.
A visible deformity is a reliable indicator of a break, where the leg may appear unnaturally shortened, crooked, or rotated outward. Swelling and bruising often develop rapidly due to internal bleeding, as the femur is highly vascular. In severe cases, known as an open or compound fracture, bone fragments may pierce through the skin, increasing the risk of infection.
If a femur fracture is suspected, the immediate response is to call emergency services. The primary goal of pre-hospital care is to prevent further movement of the broken bone. Do not attempt to move, straighten, or manipulate the injured limb.
The patient must be kept still while waiting for paramedics, as movement can worsen the injury and increase blood loss. Signs of shock, such as weakness, pale skin, and rapid pulse, must be monitored due to the potential for significant internal hemorrhage. Emergency medical professionals stabilize the limb, often using traction splints, before transporting the patient for definitive treatment.
Fixing a Broken Femur
Given the unstable nature of most femur fractures, surgery is the standard treatment option. The primary goal of surgical intervention is to achieve anatomical reduction, which means realigning the broken bone fragments into their correct positions. Once aligned, the fragments must be stabilized using internal fixation to allow the bone to heal.
The standard treatment for fractures of the femoral shaft is intramedullary nailing (IM nailing). This method involves inserting a specialized metal rod, typically made of titanium, directly into the hollow center of the femur (the medullary cavity). The rod spans the length of the fracture and is secured at both ends with screws to prevent rotation or shortening.
This internal support provides immediate stability, allowing the bone to heal and reducing the risk of complications. For fractures near the hip or knee joint, plates and screws are often used instead of a rod. These devices are contoured metal plates secured to the outside surface of the bone with multiple screws, providing structural support to complex fractures involving the joints.
Non-operative treatments are rare and usually only employed temporarily. Early surgical fixation is recommended to reduce complications and allow for quicker mobilization of the patient.
What to Expect During Recovery
Recovery from a femur fracture is a demanding process after surgical fixation. While initial bone healing can take months, the total recovery period often spans four to six months, or longer, before a return to full activity. The initial days focus on pain management and early, gentle movement to prevent stiffness and reduce the risk of blood clots.
Physical therapy (PT) is a necessary component of rehabilitation, often starting within the first 24 to 48 hours post-surgery. A physical therapist guides the patient through a transition from non-weight-bearing to partial, and eventually full, weight-bearing status. This timeline is determined by the surgeon based on X-ray evidence of bone healing. Exercises focus on range of motion for the hip and knee, followed by strengthening exercises for the surrounding muscles to support the healing bone.
Regaining strength and mobility is a gradual effort, and the use of assistive devices like crutches or a walker is necessary for an extended period. Potential complications include non-union, where the bone fails to heal, or hardware irritation from the internal fixation devices. Adherence to the physical therapy program is influential in determining the final functional outcome and the patient’s ability to return to pre-injury activity levels.