Leg Nonunion: Causes, Diagnosis and Treatment

What is it?
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Why does it occur?
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How is it treated?
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Can it heal?
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What is a leg nonunion?

A leg nonunion is a complication in which a fracture fails to heal despite sufficient time having passed for normal bone healing. In other words, the bone is unable to unite, and abnormal movement persists between the fracture fragments, preventing the formation of a stable bone callus.

In most cases, the term leg nonunion refers to a tibial nonunion, as the tibia is the bone most commonly affected due to its limited soft tissue coverage, relatively poor blood supply in certain areas, and the high incidence of complex or open fractures.

Without appropriate treatment, spontaneous healing is rare, if not impossible. Achieving bone union generally requires a specialized approach that addresses both the mechanical problem (fracture instability) and the biological problem (insufficient bone regeneration). Depending on the individual case, treatment may involve an external fixator based on the principles of the Ilizarov technique, an intramedullary nail, a plate, a bone graft, or advanced reconstructive procedures such as bone transport.

What is tibial nonunion?

The tibia is the long bone most frequently affected by nonunion because of anatomical and biological characteristics that make healing more difficult than in other bones. In particular, limited soft tissue coverage, relatively poor blood supply in certain portions of the bone, the high incidence of high-energy trauma and open fractures, together with the increased risk of infection, all increase the likelihood that a tibial fracture will fail to heal properly. For this reason, early diagnosis and treatment by a surgeon experienced in limb reconstruction are essential.

Main causes and risk factors for leg nonunion

• severe trauma
• open fracture
• infection
• instability
• smoking
• diabetes
• obesity
• poor blood supply
• bone loss

Symptoms

• persistent pain
• inability to bear weight
• swelling
• deformity
• abnormal movement at the fracture site
• limping

Diagnosis

• clinical examination
• X-rays
• CT scan
• blood tests
• microbiological cultures, when indicated

Types of nonunion

Type	Characteristics	Main treatment
Hypertrophic	Viable bone but unstable fixation	Stabilization
Atrophic	Reduced biological activity	Stabilization + bone grafting
Infected	Presence of bacteria	Debridement + reconstruction
With bone loss	Bone defect	Bone transport or reconstruction

How is nonunion treated?

External fixator

In the most complex cases, treatment of tibial nonunion may require the use of an external fixator. This technique stabilizes the fracture, corrects deformities, treats infection when present, and, when necessary, reconstructs even large bone defects. The most widely used methods include the Ilizarov circular external fixator and the more modern hexapod external fixator, which allows highly precise and programmable corrections while progressively adapting treatment to the patient’s clinical progress.

Treatment of nonunion using the Ilizarov technique

The Ilizarov technique represents one of the greatest advances in limb reconstruction surgery and is still regarded as the gold standard for the treatment of complex tibial nonunions, particularly when infection, bone loss, or associated deformity is present. Using a circular external fixator, this method stabilizes the fracture, stimulates bone regeneration, and progressively corrects limb alignment, achieving high healing rates even in the most challenging cases.

In recent years, the biological principles developed by Professor Gavriil Ilizarov have been combined with the technological evolution of the hexapod external fixator. This system pursues the same biological objectives as the traditional technique but employs six adjustable struts and dedicated software to plan and perform highly accurate three-dimensional corrections. For this reason, the hexapod external fixator is now considered one of the most advanced solutions for treating nonunions associated with complex deformities or limb length discrepancies.

Treatment of nonunion with a hexapod external fixator

The hexapod external fixator is one of the most advanced developments in external fixation and is particularly indicated for the treatment of complex tibial nonunions. Consisting of two rings connected by six adjustable struts, it allows highly accurate three-dimensional corrections by progressively modifying the position of the bone fragments without the need for additional surgery.

Dedicated software generates a personalized correction schedule based on radiographic measurements and deformity parameters. The patient then performs small daily adjustments of the struts according to a predefined schedule, allowing gradual, controlled, and highly accurate correction.

This technique is particularly useful when nonunion is associated with limb deformity, bone loss, infection, or limb length discrepancy, situations in which several problems must be corrected simultaneously. In most cases, the hexapod external fixator allows early weight-bearing, promoting bone regeneration and functional recovery.

Advantages of the hexapod external fixator

• Highly accurate three-dimensional correction.
• Possibility of modifying the correction during treatment without additional surgery.
• Simultaneous treatment of nonunion, deformity, and limb length discrepancy.
• High effectiveness even in complex or recurrent cases.
• Possibility of walking with progressive weight-bearing in most patients.
• Reduced need for additional surgical procedures to correct limb alignment.

Treatment of nonunion with a bone transport, telescopic, or static intramedullary nail

An intramedullary nail is a valid option for the treatment of selected tibial nonunions. As it is positioned entirely inside the bone, it is generally more comfortable for the patient than an external fixator, facilitates daily activities, and does not require wires or pins passing through the skin.

However, it cannot be used in every case. In the presence of complex deformities, nonunions associated with significant bone loss and, above all, infection, an intramedullary nail is often contraindicated or may not represent the most appropriate option. In these situations, an external fixator, particularly when used according to the Ilizarov technique or as a hexapod external fixator, allows simultaneous control of the infection, correction of the deformity, and stimulation of bone regeneration, thereby offering a greater chance of healing.

Treatment of nonunion with plate fixation

Plates are a valid treatment option in selected cases of nonunion, but their indications in tibial nonunion are generally limited. Compared with an intramedullary nail, they generally provide less mechanical stability in tibial nonunions, particularly when the fracture is exposed to high loads, and they require a wider surgical exposure with more extensive soft tissue dissection.

For this reason, their use is reserved for specific situations, often in combination with autologous bone grafts, when the characteristics of the nonunion make this approach appropriate. By contrast, in forearm nonunions, plates represent one of the standard treatment options. Thanks to the stability they provide and the possibility of combining them with bone grafting, they allow high union rates and accurate restoration of the anatomy and function of the limb.

Treatment of nonunion with bone grafts

Bone grafts are an important resource in the treatment of nonunion because they increase the biological potential for healing and promote new bone formation. They may be used alone in selected cases or, more frequently, in combination with fixation devices such as plates, intramedullary nails, or external fixators. However, their indication must be carefully assessed on a case-by-case basis. In the presence of active infection, bone grafts are generally contraindicated until the infection has been completely eradicated, as their use could compromise the success of treatment and promote persistence of the infectious process. In these cases, it is essential to treat the infection first and subsequently reconstruct the bone defect using the most appropriate strategy.

Bone transport

Bone transport, developed according to the principles of the Ilizarov technique, is one of the most advanced procedures in limb reconstruction surgery and is mainly used for nonunions associated with large bone defects, often resulting from high-energy trauma, infection, or previous surgical procedures. The procedure involves performing an osteotomy in a healthy segment of bone and gradually transporting it towards the defect using an external fixator or a bone transport or lengthening intramedullary nail, exploiting the mechanisms of bone regeneration described by Professor Gavriil Ilizarov. During transport, new bone forms within the space created, allowing reconstruction of the missing segment without the need for massive bone grafts.

The Ilizarov technique is currently recognized in the international scientific literature as one of the principal reference treatments for the most complex nonunions, particularly in the presence of infection, deformity, or major bone loss. In my clinical experience, as well as that of the limb reconstruction team with which I trained and continue to collaborate at the Ilizarov Centre in Lecco, this technique has achieved extremely high union rates even in cases considered particularly challenging, often representing the best opportunity for limb salvage and functional recovery.

Induced membrane technique (Masquelet technique)

The induced membrane technique, also known as the Masquelet technique, is a reconstructive procedure indicated for the treatment of selected nonunions associated with bone loss. The treatment is performed in two surgical stages. During the first stage, thorough debridement of the affected area is carried out and the defect is temporarily filled with an antibiotic-loaded cement spacer, which induces the formation of a biologically active membrane. During the second procedure, the spacer is removed and the defect is filled with bone graft, taking advantage of the biological properties of the membrane to promote bone regeneration.

The international literature reports good outcomes, particularly in small- and medium-sized bone defects. However, in more extensive bone defects and more complex nonunions, union rates are generally lower than those achieved with bone transport techniques based on Ilizarov principles. Moreover, because this is a two-stage procedure requiring large amounts of bone graft, it may be associated with complications, including persistent or recurrent infection when debridement is incomplete.

For these reasons, the Masquelet technique is best indicated for limited bone defects and in selected anatomical regions, such as in cases of forearm nonunion, where it represents a valid reconstructive alternative and may provide excellent functional outcomes in carefully selected patients.

How long does recovery take after treatment for nonunion?

The duration of recovery depends on the complexity of the nonunion, the presence of infection, any associated bone loss, and the surgical technique used. In simpler cases, bone union may be achieved within approximately 3–6 months. In more complex nonunions requiring bone reconstruction, bone transport, or treatment of chronic infection, the therapeutic pathway may last 12–18 months. In cases involving large bone defects associated with severe infection, treatment may require up to 2 years. Throughout the entire treatment period, regular clinical and radiographic follow-up, together with an appropriate physiotherapy programme, is essential to promote healing and restore limb function.

Can the patient walk again?

Yes. The primary objective of nonunion treatment is to achieve bone union and allow the patient to walk again without pain and with a stable, functional limb. In most cases, appropriate treatment combined with a structured rehabilitation programme makes it possible to regain good walking independence and return to normal daily activities.

In more complex cases, particularly when severe infection or major bone loss is present, recovery may take longer. Nevertheless, the objective remains to save the limb, achieve healing of the nonunion, and restore the best possible function.

The results obtained in our clinical cases demonstrate that, even in the most complex situations, it is often possible to achieve bone union and enable patients to return to walking and an active life.

What complications may occur?

As with any surgical procedure, the treatment of nonunion may be associated with complications. The type of complication depends mainly on the technique used, the severity of the nonunion, the presence of infection, and the patient’s general health.

With an external fixator, superficial infections may develop around the wires or pins. These are generally manageable with local wound care and antibiotics. With plates and intramedullary nails, possible complications include persistent nonunion, loosening or failure of the fixation devices, and, less commonly, deep infection. Reconstructive techniques such as bone transport or the induced membrane technique (Masquelet) may require additional procedures during the course of treatment. Severe infections may also worsen the clinical situation and make it necessary to change the treatment strategy to external fixation.

In most cases, these complications can be treated successfully, although they may prolong the healing period and require additional procedures or surgery. For this reason, it is essential to be treated by a surgeon experienced in limb reconstruction and to follow the prescribed programme of clinical reviews and rehabilitation carefully.

In the most complex cases, particularly in the presence of infection, major bone loss, or failure of previous procedures, treatment with an external fixator and bone transport according to the principles of the Ilizarov technique represents a reference standard in limb reconstruction surgery. The international literature reports union rates generally above 90% in specialist centres. In our clinical experience, through careful patient selection and the application of limb reconstruction principles, we have achieved healing rates approaching 98%, including in highly complex cases previously treated unsuccessfully at other centres and with other techniques.

How much does treatment cost?

The cost of treating a leg nonunion depends on several factors, including the type of nonunion, the presence of infection, any associated bone loss, the surgical technique used, and the number of procedures required.

As a general indication, treatment with an external fixator may cost approximately €9,000–€28,000, depending on the complexity of the case. For patients eligible for treatment with an intramedullary nail, the cost may reach approximately €40,000, particularly when the latest-generation intramedullary devices are used.

The treatment plan and corresponding quotation are always established after a specialist consultation, based on the characteristics of the nonunion and the individual needs of the patient.

Clinical cases

This section can make the website particularly informative by showing the complete treatment pathway from the initial condition to final healing.

Case

Initial X-rays

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Surgical treatment

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Healing

What is a leg nonunion?

A leg nonunion occurs when a fracture fails to heal within the expected period and abnormal movement persists between the bone fragments.

Why does it occur?

It may be caused by fracture instability, inadequate blood supply, severe soft tissue damage, infection, bone loss, smoking, diabetes, or failure of previous surgical treatment.

How is it treated?

Treatment depends on the characteristics of the nonunion and may involve an external fixator, an intramedullary nail, plate fixation, bone grafting, the Masquelet technique, or bone transport according to the principles of Ilizarov.

Can it heal?

Yes. With appropriate specialist treatment, most nonunions can heal. Even in complex cases involving infection or major bone loss, advanced limb reconstruction techniques can often achieve bone union, preserve the limb, and restore walking function.