The fibula is the smaller of the two bones in the lower leg, running parallel to the larger, weight-bearing tibia. The fibula head (proximal fibula) is the expanded upper end of this bone, located just below the knee joint on the outside of the leg. A fracture here is common, often resulting from direct trauma or a twisting force to the knee. This injury requires immediate medical evaluation to assess damage to surrounding structures.
The Immediate Answer: Mobility After Injury
Attempting to walk or place weight on a leg with a fractured fibula head is strongly discouraged immediately following the injury. While the fibula is not the primary weight-bearing bone, putting force on the injury can be painful and lead to complications. The primary risk of weight bearing is causing displacement of the fracture fragments, shifting the broken pieces out of alignment. This movement can disrupt the adjacent joint surfaces or tear the ligaments that attach to the bone.
Immediate, unprotected weight bearing can also jeopardize the common peroneal nerve, which wraps closely around the fibula head and neck. Further displacement of the bone fragments could compress or stretch this nerve, potentially causing numbness, tingling, or even foot drop. Seeking immediate medical care is necessary to confirm the diagnosis and prevent further injury. Until professional help is reached, the limb should be immobilized and kept in a non-weight-bearing position.
Understanding the Fibula Head’s Role
The location of the fibula head makes it a mechanically significant site, even though the fibula only bears about 10% of the body’s weight. The head forms an articulation with the tibia called the proximal tibiofibular joint, which contributes to knee stability. This small joint allows for slight movement that helps dissipate rotational forces on the lower leg.
The fibula head acts as an anchor point for several structures, including the biceps femoris tendon and the fibular collateral ligament (LCL). The LCL is a stabilizer on the outside of the knee, and a fracture can compromise its function, leading to knee instability. The common peroneal nerve also runs directly behind the fibula head, making the fracture site vulnerable to nerve damage.
Standard Treatment Protocols for Healing
Management for a fibula head fracture is determined by the stability and displacement of the bone fragments. Non-operative treatment is used for stable fractures that are non-displaced or minimally displaced, meaning the bone pieces remain in alignment. This approach involves initial pain management, often using rest, ice, compression, and elevation (RICE), followed by immobilization. Immobilization may involve a brace or cast, and patients are instructed to maintain strict non-weight-bearing status on the injured leg.
Operative management (surgery) is required when the fracture is displaced, involves the joint surface, or is associated with ligamentous instability. If the fibula head is avulsed (a ligament or tendon pulled a piece of bone away), surgery may be needed to reattach the fragment and restore stability. The goal of surgery is to reduce the fracture fragments and stabilize them, often using internal fixation hardware such as plates, screws, or suture anchors. This fixation allows the bone to heal in the correct position and is necessary if associated injuries, such as damage to the knee’s posterolateral corner structures, exist.
Phased Approach to Weight Bearing and Recovery
The progression toward walking is a phased process guided by orthopedic imaging and physician approval. The initial phase involves two to four weeks of strict non-weight bearing, often requiring crutches or a knee scooter to prevent load on the affected limb. During this time, the body begins the initial stages of bone healing, and follow-up X-rays confirm that the fracture remains stable.
The next stage allows for a shift to partial weight bearing (PWB), starting with touch-down weight bearing (10% to 20% of body weight) before progressing to 50%. This progression occurs between four and eight weeks post-injury, but only once the doctor confirms sufficient healing. Physical therapy begins during this period to regain the knee’s range of motion and prevent muscle atrophy. Full weight bearing and walking without assistance are gradually introduced as pain decreases and strength improves, usually around six to eight weeks. Complete recovery can range from three to six months.