Updated December 2023

Tell many friends that you have a fibula fracture, and they’ll often reply, “It’s not a problem. It’s not a weight-bearing bone.” However, your friend doesn’t have the fracture. Trust us. Trying to heal from a fracture on the fibula can be painful, long, and difficult. Just because it doesn’t bear all the leg’s weight, it does bear some. The possible pain and inflammation can cause you to stay off your feet and slow your healing.

Runner laying on the ground with pain from a fibula fracture.
A fibula fracture can be painful and slow to heal.

What is the Fibula Bone?

The fibula is a slender, long bone outside the lower legs. It runs from underneath the knee and down to the ankle joint. Next to the fibula bone is the tibia bone, the thicker bone of the two. Together, they form the base of the knee (called the tibial plateau).

The tibia and fibula are connected by ligaments underneath the knee and at the ankle. There is also a soft tissue between the two bones, called the interosseous membrane, which runs the length of the two bones. The interosseous membrane binds the two bones together to keep them stable. The ligaments and the interosseous membrane have a little flexibility in them, allowing the ankle joint and the two bones to move during walking and motion of the ankle. The fibula can bend slightly, and it can also rotate within its ligament. It can also slide up and down during ankle motion, inward and outward.

The fibula bone plays a minor role in bearing the body’s weight as we walk. The tibia bears approximately 80% of the body’s weight. The fibula bone bears only 15 to 20% of the body’s weight. Moreover, it transfers forces as the ankle hits the ground during walking. The mechanism of transferring ground reaction forces occurs due to muscle attachments on the upper part of the fibula bone underneath the knee. The interosseous membrane also helps transfer rotational forces from the ankle to the knee. Some nerve tissues, veins, and arteries pass behind the fibula near the knee. The fibula is a site of five muscle attachments.

How to Get a Fibula Fracture

Fibula bone fractures are a common injury in the emergency room. Often, a fracture occurs from:

  • A direct blow to the outside of the leg;
  • From twisting the lower leg awkwardly and
  • From a severe ankle sprain.

The injury is common in athletes who engage in contact sports such as soccer, football, basketball, rugby, and Lacrosse. Downhill skiers, snowboarders, and skiers also have high rates of fibula bone fractures. In elderly people, slips and falls often cause fibula bone fractures.  It could also occur when bone mass depletes in the elderly. Moreover, surprisingly, smoking is an important risk factor for fibula bone fracture.

Recovering from a Fibula Bone Fracture Takes Time

All bones heal in three phases: inflammation, repair, and remodeling.

The Inflammation Phase Takes about Five Days

As the bone fractures, it bleeds. It’s that bleeding that causes inflammation. The blood or hematoma (blood clot) enters the space between the two fractured fragments to initiate healing or the repair process. 

The Repair Phase Takes About 40 Days

A soft callus is formed across the fractured site during the repair phase. The soft callus fills the bone, developing into a hard, rigid callus.

The Remodeling Phase Takes about 100 Days

After the hard, rigid callus is formed, the remodeling phase starts.  In this phase, the bone remodels itself into its original size and regains its strength properties. This phase takes 100 days.

What Makes Healing a Fibula Fracture Difficult

The average time for bone healing is 8 to 10 weeks, and the complete healing time is 12 to 16 weeks. The natural healing time should be allowed to take its usual course. If you choose to be active, you can cause a lot of problems:

  • Interference with the natural healing time, such as not following the weight-bearing status from the physician, can displace the hematoma, and the bone cannot heal.
  • Too much motion early at the fractured site prevents the hard, rigid callus from forming, resulting in non-union of the fracture fragments. The fractured site can then become unstable. 
  • Poor blood supply to the fractured site also prevents the formation of the hard, rigid callus. That is why smokers have a hard time healing. Smoking decreases blood supply to the fracture site.

Where Does the Fibula Bone Fracture Occur?

There are different locations where the fibula bone can fracture. For example, the fracture can occur at the knee joint, above the ankle, in the shaft of the fibula bone, and at the ankle joint.

The tip of the fibula bone at the ankle joint can also separate, called an avulsion fracture. This happens from a severe ankle sprain. The location of the fracture dictates restrictions placed on a patient. On an isolated fracture, such as a fracture in the shaft of the fibula bone, that fracture is uncomplicated, and confidence for complete healing is high.

However, fractures at the knee and ankle take longer to heal, and restriction and immobilization are critical to healing. A fracture at the knee is associated with complications due to the muscles, ligaments, and interosseous membrane attachments in that location.

Most physicians’ concern at this location is the surrounding nerves, veins, and arteries. Complications can become more of a concern when the fracture is above or at the ankle joint. The concern is tearing the ligaments that connect the tibia bone and the fibula bone that form the ankle joint.

The restriction and immobilization are severe due to instability. One must take into account here the time it takes for bone and ligaments to heal before putting weight on it, as both tissues heal at different times.

Woman who had a fibula fracture.

How to Treat a Fibula Fracture

Doctors heal a fibula fracture with immobilization. This is done either with a CAM walker boot or with surgically installed screws and plates (depending on the distance between the fractured fragments). The larger the distance between the fragments, the more immobilization is required because healing depends on the hematoma fitting the space between the fragments.

The hematoma initiates the healing process: growing from a soft callus to a hard, rigid callus to remodeling. Immobilization with a boot or surgery brings the fractured segment closer so the blood clot can fit the space to initiate healing.

Excessive or early weight bearing can displace the blood clot and interrupt healing. This is why physicians recommend non-weight bearing for the first 4 to 6 weeks.

Remember that it takes four to six weeks for the hard, rigid callus to form and for remodeling to begin. At this time, weight-bearing becomes essential in helping the bone remodel to its original size.

Moreover, control or gradual weight bearing is paramount. Weight-bearing on the healing leg progresses from non-weight bearing to touch weight bearing, partial weight bearing to weight bearing as tolerated, and finally to full weight bearing. Fibula bone fractures heal faster than weight-bearing bones, such as the tibia. Complications can arise from weight bearing and early motion at the fracture site.

Immobilizing the Leg is Key to Healing

Patient with a CAM walking boot.
The CAM Walking Boot Reduces Fibula Stress

Immobilization is paramount in the healing process. It keeps the distance between the fracture fragments close to allow healing to take place, as explained earlier. It compresses the fractured fragments to support and keep the bone stable. Compression also takes stress off the surgical stitches.

Several types of immobilization are used to treat fibula fracture, such as a CAM walking boot, which comes in non-inflatable, adjustable inflation, allows range of motion, and a rock bottom boot.

  • The CAM walking boot wraps the foot, ankle, and lower leg below the knee.
  • The non-inflated CAM walker provides basic support to the fractured fragments.
  • The inflated CAM walking boot is where the bladder is inflated with air to increase stability and accommodate swelling in the leg.
  • The range of motion boot is adjusted to allow a restricted range of motion.
  • The rock bottom boot allows natural rocking motion on the foot during walking. As the fractured leg heals, the CAM boot is replaced by a plastic air stirrup-type brace or an ankle laced-up brace.

Remember the R.I.C.E.

After immobilization, use the RICE principle to manage swelling and pain. “RICE” stands for:

  • Rest the injured/surgical leg,
  • Ice the injured leg,
  • Compression is applied to the injured leg using an ace wrap, and
  • Elevation of the injured leg above the heart to drain the swelling.

One key to success after a surgical procedure is to use compression and elevation to decrease swelling. The faster the swelling subsides, the faster there is recovery.

Don’t Put Weight on Your Leg

Non-weight bearing means no weight on the healing leg. You can reduce stress on your leg with a wheel walker, crutches, or a knee scooter. Anything to reduce weight on your leg helps promote healing.

What is Touch Weight Bearing

Touch weight bearing is when the foot and toes are touching the floor. It gives the muscles of the leg a break from holding the leg up. It also helps the leg to become accustomed to minimal weight bearing.

Partial Weight-Bearing 

Partial weight-bearing gradually allows the leg to hold more weight – up to 50% of your body’s weight. During this phase, your body weight is equally distributed on the healing leg and the assistive device. Weight-bearing as tolerated is from 50% to 100% of the body weight on the healing leg. Finally, full weight bearing is 100% of the body weight on the healing leg with no assistive device. Weight-bearing on the healing leg progresses from non-weight bearing to touch weight bearing, partial weight bearing to weight bearing as tolerated, and finally to full weight bearing.

A Final Word about a Fibula Fracture

A word on fibula bone stress fracture: It is not a true fracture. It is called a hairline fracture due to repetitive stress on the fibula bone. The fracture fragments are not separated. One can think of it as a crack in the bone. During long-distance running, hiking, and so forth, the bone reacts to excessive stress, resulting in a hairline fracture. Activity increases the pain, and rest decreases the pain. Removing the stress on the bone is the only way to recovery.

Call STARS at (208) 367-3315 if you have any questions regarding fibula fracture.

Article Credit: Raj Issuree, MPT


References:

  • McKibbin B. The biology of fracture healing in long bones. J Bone Joint Surg 1978; 60-B (2): 150-162
  • Perren SM, Rahn BA. Biomechanics of fracture healing. Can J Surg 1980; 23(3): 228-32
  • Connolly JF, Maha H et al. Fracture healing in weight-bearing and non-weight-bearing bones. J Trauma 1978; 18(11); 766-70

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