How to Tell the Difference Between a Malunion and Nonunion Fracture

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When a bone breaks, it needs to heal properly in order for the person to resume normal activities. However, sometimes fractures do not heal correctly due to various factors, such as inadequate treatment or insufficient blood supply. In such cases, the fracture can be described as either nonunion or malunion. Read on to learn more about nonunion and malunion fractures and how they are treated. 

Growth Factors and Bone Healing 

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When a bone breaks, the body's natural healing process kicks into gear. Some of the key players in this process are growth factors, naturally occurring chemicals that help to promote bone healing. 

Growth factors are essential proteins that help regulate cell activity during bone healing processes. They work by signaling cells to produce new bone tissue, cartilage, and collagen fibers—all of which are important for the healing process. When these growth factors are produced in a certain sequence, it helps ensure that the broken bones will properly heal together without any misalignment of the bones after healing. 

When the body's natural healing process is disrupted, it can lead to a variety of negative outcomes such as nonunions and malunions. 

What Is a Nonunion Fracture? 

If you have experienced a non-displaced fracture (where the broken parts are still aligned), but there isn’t any evidence of healing after 6 months, it may be considered a non-union fracture. A nonunion fracture is when the two pieces of bone that were broken during an injury fail to heal. The bones may remain separated, which can cause chronic pain and mobility issues if left untreated. 

How Long Before a Fracture is Considered Nonunion? 

Every fracture has the potential to heal, however some fractures can take longer than others. Generally, a fracture is considered non-union after 6 months of immobilization. “For a nonunion, we need to prove there is no growth and no possibility of [bone] growth,” says orthopedic surgeon Dr. Reyes. “Most of the time, it is a delayed union, and after 6 months, many doctors will declare a nonunion.” After three months of no signs of healing, your doctor may try more aggressive measures encourage your bone to heal. More complex fractures, such as ones that occur in the presence of infection or poor blood circulation may take up to 6 months or even more before they are considered non-union. 

What is a Malunion Fracture? 

A malunion fracture is similar to a nonunion fracture in that it occurs when two pieces of broken bone fail to grow together properly; however, with a malunion fracture, healing does occur but not in its intended or desired shape. In other words, the bones heal into an improper alignment rather than their original positions before fracturing. This can lead to long-term complications such as pain and limited mobility around the joint due to misalignment and decreased flexibility in that area. 

Symptoms of Nonunion and Malunion Fractures 

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The most common symptom of both nonunion fractures and malunion fractures is persistent pain in the affected area, which does not go away even after rest and medication has been taken. Other symptoms may include swelling, stiffness, or deformity in the affected area, as well as limited mobility due to muscle weakness. In some cases, you may also experience numbness or tingling in the affected area. 

Causes of Nonunion and Malunion Fractures 

When a bone is fractured, it’s critical that it heals correctly. However, sometimes the healing process can go awry, resulting in malunion or nonunion. Let’s look at the various factors that can contribute to the healing process being delayed or interrupted:


One of the most common causes of a malunion or nonunion fracture is infection. Bacteria can enter the site of the fracture and interfere with healing, resulting in inadequate recovery. Common signs of infection include redness, warmth, swelling, drainage from the wound site, fever, chills, and increased pain at the injury site. If you notice any of these signs following an injury or surgery that required a cast or splint to immobilize the area, it’s important to seek medical attention as soon as possible. 

Inadequate Blood Supply in Bone 

Another key factor for successful fracture healing is adequate blood supply to the bones involved. Without sufficient blood supply, vital nutrients cannot reach the area, and there will be reduced rates of healing and even cell death in the case of extreme deprivation. This could be due to poor circulation or underlying medical conditions that limit blood supply such as diabetes or vascular disease. 

Improper Stabilization of the Bone After Injury or Surgery

If a fracture is not stabilized adequately after it has occurred—for example if someone sets their own broken bone instead of seeking medical treatment—it may be more difficult for it to heal correctly due to lack of stability at the injury site. If your fracture is unstable, your doctor may recommend surgery as soon as possible in order to reduce any potential complications that could arise from an inadequately stabilized fracture site. 

Malunion and Nonunion Diagnosis

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Diagnosing malunion or nonunion usually requires a thorough evaluation. Your doctor may order X-rays, MRI scans, and/or CT scans of the bones and surrounding tissues to get a better picture of what’s going on. Additionally, if there is suspicion of a nonunion, your doctor may also need to run blood or urine tests to investigate for any potential underlying causes for this condition. Through this comprehensive approach, doctors are able to pinpoint an accurate diagnosis and treatment plan.

Malunion and Nonunion Treatment Options

The treatment for nonunions and malunions vary depending on how severe the condition is and what caused it in the first place.

Treatment Options for Nonunions 

Nonunions generally require surgery in order to promote healing and restore mobility to the affected area. Surgery typically involves internal fixation with screws or plates in order to secure the bones while they heal. Bone grafting may also be necessary in some cases in order to provide additional support for proper healing. Depending on your particular situation and medical history, your doctor may recommend physical therapy following surgery in order to regain strength and range of motion in your limb or joint affected by the nonunion fracture. 

Treatment Options for Malunions 

Treatment of a malunion fracture typically depends on the severity and origin of the injury. If misalignment has caused disfigurement, surgery may be necessary to correct it. In these cases, focus is not only placed upon restoring the appearance of the bone but also its alignment in order to reduce stress on any adjoining joints. Depending on the condition of the malunion fracture, surgical methods can vary including straightening and internal or external fixation devices such as plates or screws. Although corrective surgery carries some risk, it often improves your ability to use the bone in most circumstances and restore form and function as much as possible.

Cast21 Orthopedic Alternative for Nonunion and Malunion Fractures 

The Cast21 orthopedic alternative is a revolutionary new way to treat nonunion and malunion fractures that offers an alternative to clunky, uncomfortable casts of the past. The process includes a special liquid formula which is contained in a special pack, and when poured onto the sleeve, hardens and molds to the patient’s body for a custom fit. Not only does this system reduce discomfort and irritation, but it’s also less invasive than traditional methods of treatment. It’s no wonder many medical professionals are turning to the Cast21 alternative as a convenient and comfortable solution for orthopedic conditions.

If you are interested in switching to the Cast21 System, ask your doctor about Cast21 or contact us for more information. 

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