Femoral Nonunion: Causes, Diagnosis and Treatment
What is a femoral nonunion?
A femoral nonunion is a condition in which a fracture of the femur fails to heal properly and the normal bone-healing process comes to a halt. It may occur after particularly complex fractures, high-energy trauma, or even after previous surgery using an intramedullary nail, plate and screws, or other fixation devices.
It is important to distinguish nonunion from delayed union. In delayed union, the bone is still healing, but more slowly than expected; in nonunion, on the other hand, healing does not show sufficient progression and treatment may be required to restore the biological and mechanical conditions necessary for bone union.
Femoral nonunion may affect different regions of the femur, from the proximal and subtrochanteric region to the femoral shaft and the more distal regions. Causes, characteristics and treatment may differ depending on the location and type of the original fracture.
The acquired femoral nonunion discussed on this page should not be confused with the rare congenital pseudarthrosis, which occurs in children and is related to completely different conditions.
In many cases, femoral nonunion can be treated successfully, but it is essential first to understand the cause: a stability problem, reduced biological capacity to form new bone, infection or, in more complex cases, a combination of these factors. The choice of the most appropriate treatment depends on this assessment.
Why can a femoral fracture fail to heal?
Healing of a femoral fracture requires two fundamental conditions: adequate mechanical stability and a good biological capacity of the bone to form new tissue. A third key factor must also be present: the absence of infection. When one or more of these factors are lacking, healing may slow down and eventually stop, leading to a femoral nonunion.
Mechanical problems and fracture instability
One of the most important causes is insufficient stability at the fracture site. Even after surgery with an intramedullary nail or plate, excessive movement may persist between the bone fragments and prevent proper healing.
In other cases, there may be suboptimal alignment, loss of contact between the fragments, a bone defect or, over time, loosening or breakage of the fixation devices.
When the bone retains good biological healing potential but the main problem is instability, a hypertrophic nonunion may develop. This is characterised by abundant callus formation that nevertheless fails to complete the healing process.
Biological problems: when the bone cannot heal
In other patients, stability may be relatively adequate, but the biology of healing is impaired.
High-energy trauma, open fractures, major soft-tissue damage, repeated surgical procedures, bone loss and impaired blood supply can reduce the body’s ability to produce new bone.
In these situations, an atrophic nonunion may develop, in which the formation of new bone tissue is limited. Treatment may therefore require not only improved stabilisation, but also procedures aimed at restoring the biological capacity for healing, such as the use of an autologous bone graft.
Infection and septic femoral nonunion
Another particularly important cause is infection. A nonunion may be associated with an obvious infection, with wound drainage, sinus tracts, redness or other clinical signs, but in some cases the infection may be less apparent and present mainly as failure of fracture healing.
Distinguishing between aseptic and septic femoral nonunion is essential because it radically changes the treatment strategy.
In the presence of infection, it may be necessary to remove infected tissue and bone, obtain microbiological samples, manage any contaminated fixation devices and subsequently reconstruct stability and any bone defects.
Often there is more than one cause
In more complex nonunions, mechanical, biological and infectious problems may coexist. A fracture that was initially very severe may simultaneously present bone loss, poor blood supply, instability and infection.
For this reason, before deciding how to treat a femoral fracture that is not healing, it is essential to identify the main obstacle to healing. Simply replacing a nail or adding a bone graft without understanding the cause of the nonunion may not be sufficient.
Treatment must therefore be planned to correct, when necessary, mechanical stability, bone biology and infection: three elements that must be considered together in order to achieve stable union.
Symptoms: how can you tell if the femur is not healing?
After a femoral fracture, recovery naturally takes time, but when healing does not progress correctly, certain signs may suggest delayed union or femoral nonunion.
The most common symptom is persistent pain at the fracture site, especially during weight-bearing and walking. Over time, pain should generally decrease; if it remains significant, returns as weight-bearing increases, or does not show progressive improvement, the state of fracture healing should be assessed.
Another sign is difficulty regaining weight-bearing on the limb. The patient may continue to need crutches, limp, or feel that the leg is not sufficiently stable. In more significant nonunions, abnormal mobility at the fracture site may also be present.
Radiographic follow-up is essential
Symptoms alone are not sufficient to make the diagnosis. A particularly important sign is the lack of progression of healing on serial X-rays over time.
Comparing subsequent X-rays makes it possible to evaluate callus formation and determine whether the fracture is actually progressing towards healing.
In some cases, the first obvious sign of the problem may be failure of the fixation device. An intramedullary nail, a plate or screws may loosen or, in more advanced cases, break because of repeated loading on a fracture that has not healed.
Therefore, breakage of a fixation device does not necessarily represent the initial problem, but may be the consequence of a persistent nonunion.
For this reason, when pain and difficulty with weight-bearing persist longer than expected or X-rays do not show progressive healing, a specific orthopaedic assessment of femoral union is indicated before the problem becomes more difficult to treat.
How is a femoral nonunion diagnosed?
The diagnosis of femoral nonunion is not based on a single test, but on the combined assessment of the clinical history, symptoms and, above all, the radiographic progression of the fracture over time.
The first examination is generally an X-ray of the femur, obtained in appropriate views and including the affected segment and any fixation devices present. Comparison with previous X-rays makes it possible to assess whether callus formation is progressing, whether a fracture line persists, and whether there are deformities, loss of contact between the fragments, loosening or breakage of nails, plates or screws.
When is a CT scan needed?
In some cases, X-rays are not sufficient to determine precisely how much bone has actually healed. A CT scan (computed tomography) can provide more detailed information about bone continuity and the morphology of the nonunion and may be useful when planning revision surgery.
It is essential to rule out infection
Before planning treatment for a nonunion, it is particularly important to determine whether it is aseptic or infected.
The assessment includes examination of the skin and previous surgical wounds and the search for signs such as sinus tracts, drainage, redness or swelling. Blood tests, including inflammatory markers, may also be requested as part of the diagnostic work-up. However, the absence of obvious clinical signs does not always completely rule out infection.
In suspicious cases, further investigations may therefore be necessary and, when revision surgery is performed, multiple deep tissue samples for microbiological and histological analysis may be essential to identify a possible infection.
This distinction is essential because an infected femoral nonunion requires a different treatment strategy from an aseptic nonunion.
The aim of diagnosis is therefore not simply to confirm that “the femur has not healed”, but to understand why: assessing mechanical stability, biological healing capacity, alignment, any bone loss and the possible presence of infection. Only after this evaluation can the correct treatment be selected.
Hypertrophic and atrophic femoral nonunion
Not all femoral nonunions are the same. A particularly useful distinction is between hypertrophic and atrophic nonunion, because it helps identify the main obstacle to healing and, consequently, which surgical strategy may be most appropriate.
Hypertrophic femoral nonunion
In hypertrophic nonunion, the bone retains good biological healing capacity. X-rays often show abundant callus formation around the fracture, but this fails to create a sufficiently stable bridge between the two segments.
In these cases, the problem is mainly mechanical: the body is trying to heal the fracture, but excessive movement, insufficient stability of the fixation system, a gap or an alignment problem prevents completion of union.
Treatment should therefore focus primarily on restoring adequate mechanical stability, while correcting deformity or other associated problems when necessary.
Atrophic femoral nonunion
In atrophic nonunion, by contrast, new bone formation is limited and the problem has a predominantly biological component.
It may occur after high-energy trauma, open fractures, major soft-tissue damage, compromised blood supply, bone loss or multiple previous surgical procedures.
In these cases, simply increasing stability may not be sufficient. It may be necessary to biologically reactivate the nonunion site, remove any non-viable tissue and use bone grafts, often autologous, in combination with adequate stabilisation.
Why is this distinction important?
The distinction between hypertrophic and atrophic nonunion demonstrates why there is no single operation suitable for all femoral nonunions.
In some patients, the main problem is stability; in others, it is the biological ability of the bone to heal. In the most complex cases, instability, biological impairment, deformity, bone loss or infection may all be present at the same time.
For this reason, treatment must be personalised: intramedullary nails, plates, bone grafts, external fixation or more complex reconstructive techniques are not interchangeable alternatives, but different tools that must be selected and, when necessary, combined according to the specific characteristics of each nonunion.
How is femoral nonunion treated?
Types of nonunion
| Type | Characteristics | Main treatment |
| Hypertrophic | viable but unstable bone | stabilisation |
| Atrophic | reduced biological activity | stabilisation + bone graft |
| Infected | presence of bacteria | debridement + reconstruction |
| With bone loss | bone defect | bone transport or reconstruction |
The treatment of femoral nonunion must be determined according to the cause that prevented the fracture from healing. There is therefore no single operation suitable for every patient: the strategy may vary considerably in the presence of mechanical instability, biological impairment, infection, deformity, limb shortening or bone loss.
The fundamental principle is to correct, when necessary, the two essential components of healing at the same time: mechanical stability and the biological ability of the bone to unite. When infection is present, it must also be identified and treated as an integral part of the reconstructive process.
Revision or replacement of the intramedullary nail
An intramedullary nail is one of the main treatment options for femoral shaft nonunion, particularly when there is no infection and limb alignment is satisfactory.
In patients previously treated with a nail, revision fixation may be indicated, possibly replacing the device with a larger-diameter nail and improving stability at the nonunion site.
In other cases, it may be necessary to change the strategy completely, particularly when deformity, bone loss, infection or previous surgical failures are present.
Plate and screws
Plate fixation can be used in different types of femoral nonunion and may represent an alternative or, in selected cases, an addition to existing fixation.
The aim is to achieve sufficient stability to allow bone union, correcting alignment or rotational problems when necessary.
The choice between nail and plate depends on the location of the nonunion, bone quality, the type of previous surgery and the mechanical characteristics of the case.
Autologous bone graft
When the nonunion has a major biological component, particularly in atrophic forms, stabilisation may need to be combined with an autologous bone graft, meaning bone taken from the same patient.
The graft helps create an environment favourable to new bone formation and can be used together with nails, plates or other stabilisation techniques.
The need for bone grafting does not depend simply on the time elapsed since the fracture, but on the biological characteristics of the nonunion and the possible presence of a bone defect.
External fixator and Ilizarov technique
An external fixator, particularly circular systems based on the principles of the Ilizarov technique, plays a particularly important role in the most complex femoral nonunions.
It may be indicated when nonunion is associated with infection, deformity, limb shortening, bone loss or previous surgical failures.
One of the main advantages of external fixation is the ability to address several components of the problem at the same time: stabilising the nonunion, progressively correcting alignment and, when necessary, reconstructing bone loss using regeneration and bone transport techniques.
Infected nonunion: infection control comes first
The presence of infection radically changes the treatment.
In these cases, it may be necessary to remove contaminated fixation devices and non-viable bone, perform thorough surgical debridement and obtain adequate stabilisation of the limb. Antibiotic therapy is planned according to microbiological results and the clinical picture.
If debridement results in significant bone loss, treatment must also address reconstruction of the bone defect.
Masquelet technique
When femoral nonunion is associated with a bone defect of a few centimetres, one reconstructive option is the Masquelet technique, also known as the induced membrane technique.
Treatment is generally carried out in two surgical stages. During the first procedure, the nonunion site is thoroughly cleaned, removing non-viable and, when present, infected bone. The resulting bone defect is temporarily filled with a cement spacer, often loaded with antibiotics when indicated, while the femur is adequately stabilised.
Over the following weeks, a biologically active membrane develops around the spacer. During the second procedure, the cement is removed while preserving this membrane and the space is filled with bone graft, usually autologous, to promote reconstruction and union of the defect.
The Masquelet technique can be highly effective in selected cases, but it requires a substantial quantity of bone graft when the defect is extensive. In large femoral bone defects, particularly when associated with infection, deformity or limb shortening, other reconstructive strategies may be more appropriate, such as bone transport using an external fixator according to the principles of Ilizarov.
The choice between Masquelet, bone transport or other reconstructive techniques therefore depends on the size and location of the defect, the presence of infection, the condition of the soft tissues and the characteristics of the individual patient.
Intramedullary bone transport nail: an innovative technique
In the most complex cases, when femoral nonunion is associated with major bone loss, a more recent technique may also be used: the intramedullary bone transport nail.
After removal of non-viable or infected bone, a defect of several centimetres may remain. A bone transport nail makes it possible to carry out progressive bone transport within the femur, slowly advancing a bone segment towards the defect while allowing new bone to form simultaneously in the distraction zone.
This is a particularly innovative application of the principles of distraction osteogenesis and bone transport, traditionally performed with external fixators.
The main advantage is the possibility, in carefully selected patients, of reconstructing major femoral defects through a predominantly internal system, reducing or avoiding prolonged periods with an external fixator.
This technique is not necessary for simple femoral nonunions. It may instead be indicated in complex nonunions with bone loss, including some situations resulting from infection, previous surgery or failure of fixation devices.
The choice between bone transport nail, Masquelet technique and bone transport with an Ilizarov external fixator must be made on a case-by-case basis, taking into account the size of the defect, the presence or absence of active infection, the condition of the soft tissues, limb alignment and previous surgical procedures.
When several techniques need to be combined
The most difficult femoral nonunions can rarely be managed by considering only one problem at a time.
A patient may simultaneously present a non-healed fracture, a broken nail, infection, deformity and loss of several centimetres of bone. In these situations, a staged reconstructive pathway or a combination of different techniques may be required.
For this reason, treatment of femoral nonunion must begin with one fundamental question:
Why has this fracture not healed?
Once the cause has been identified, the most appropriate strategy can be selected from revision intramedullary nailing, plate fixation, bone grafting, external fixation, the Ilizarov technique and procedures for reconstruction of bone defects.
The final goal is not simply to obtain an X-ray in which the fracture appears united, but to restore a stable, correctly aligned and functional femur while preserving limb length and walking ability as much as possible.
What should be done if the femur does not heal after intramedullary nailing?
Treatment depends on the cause of the nonunion. Simply replacing the nail is not always sufficient.
In some aseptic femoral shaft nonunions, replacement of the nail with a larger-diameter nail may be indicated to improve stability at the nonunion site. In other cases, it may be preferable to add or use a plate, treat the nonunion site directly and add an autologous bone graft when biological healing potential needs to be increased.
If deformity, infection, bone loss or repeated surgical failures are present, a complete change in strategy may instead be necessary, using more complex reconstructive techniques, including circular external fixators, the Ilizarov technique, Masquelet or bone transport.
When nonunion is associated with major bone loss, one particularly innovative option is the intramedullary bone transport nail. This device makes it possible to apply the principles of bone transport through an internal system: a bone segment is progressively transported towards the defect while new bone forms in the distraction zone. In selected patients, this technique can therefore reconstruct the femoral bone defect while limiting or avoiding prolonged use of an external fixator.
The choice between nail revision, plate fixation, Masquelet, bone transport nail and bone transport with an external fixator depends on the characteristics of the nonunion, the extent of bone loss and, above all, the presence or absence of infection.
Before changing the nail, it is essential to understand why it failed
This is probably the most important point. When faced with a femoral fracture that has failed to heal after intramedullary nailing, the priority should not simply be choosing a new fixation device, but identifying the cause of failure.
It is necessary to assess stability, alignment, biology of the nonunion site, any bone defect and, above all, rule out infection.
Only after this assessment is it possible to decide whether to retain, replace or remove the nail and which additional technique should be used to achieve femoral union.
Infected femoral nonunion
An infected femoral nonunion is one of the most complex conditions in limb reconstruction surgery. In these cases, achieving fracture union alone is not enough: infection, mechanical stability and the biological ability of the bone to heal must all be addressed at the same time.
The infection may be obvious, with sinus tracts, drainage and local signs, or more difficult to recognise. It may occur after an open fracture, high-energy trauma or previous surgical procedures and may also involve nails, plates and other fixation devices.
Infection debridement and femoral stability
The first goal is to achieve thorough surgical debridement, removing non-viable tissue and, when necessary, infected bone. During surgery, deep samples are obtained to identify the responsible microorganisms and guide targeted antibiotic therapy.
When an internal fixation device is involved in the infection, it may need to be removed. However, the femur must remain adequately stabilised: treating the infection without ensuring mechanical stability can make healing extremely difficult.
The role of the Ilizarov technique
It is precisely in complex infected nonunions that external fixation according to Ilizarov principles has one of its most important indications.
The major advantage is the possibility of achieving very solid stabilisation without leaving internal fixation material at the infected site. The system also makes it possible to progressively modify the biomechanics of the frame and address several problems often associated with nonunion at the same time.
With the Ilizarov technique it is possible to:
- stabilise the nonunion;
- progressively compress the nonunion site when indicated;
- correct deformities and axis abnormalities;
- restore limb shortening where necessary;
- manage major bone loss;
- perform bone transport when debridement of infection requires resection of a femoral segment.
For this reason, in cases of septic femoral nonunion associated with infection, deformity or bone loss, Ilizarov remains one of the most powerful and versatile tools in reconstructive surgery.
When debridement leaves a major bone defect
In more severe infections, it may be necessary to remove several centimetres of non-viable bone. The result is a femur free from macroscopically infected bone, but with a major bone defect that must be reconstructed.
In these cases, Ilizarov bone transport makes it possible to generate new bone using the patient’s own regenerative capacity. After an osteotomy in a healthy area of the femur, a bone segment is progressively transported towards the defect while new bone forms behind it.
In selected cases, other strategies such as Masquelet or intramedullary bone transport systems may also be considered. However, particularly when infection is active or the local situation is especially complex, the ability to reconstruct without introducing internal material into the infected site is one of the major advantages of external fixation.
Treating the infection is not enough: the limb must be reconstructed
The final goal of treatment is not simply to eradicate the infection. The aim is to achieve a united, stable and correctly aligned femur with the most appropriate possible limb length.
It is precisely this combination of infection debridement, stabilisation and bone reconstruction that makes infected femoral nonunion one of the areas in which the Ilizarov technique continues to play a fundamental role.
Femoral nonunion with bone loss
Femoral nonunion with bone loss is one of the most complex forms of failed fracture healing. It may occur after high-energy trauma, open fractures, infection or following the surgical removal of non-viable bone segments. In these cases, the problem is not only to achieve fracture union, but to reconstruct the missing bone segment while preserving limb length, alignment and function.
The strategy depends on the extent of the defect and the presence of infection. Available options include the Masquelet technique, bone transport using an Ilizarov external fixator and, in selected patients, more recent intramedullary bone transport nails. In larger defects, bone transport allows progressive regeneration of new bone while simultaneously restoring femoral length.
However, large bone defects require specific planning and deserve separate consideration. For this reason, we have dedicated a guide to complex nonunions with large bone defects, comparing bone transport, Ilizarov, Masquelet and modern intramedullary reconstructive techniques.
How long does it take to heal from a femoral nonunion?
Healing times for a femoral nonunion can vary considerably from one patient to another. In relatively simple cases, without infection and with good biological bone quality, union may be achieved in approximately 3–4 months after surgery, but in most cases the process takes longer. In more complex nonunions, treatment may require many months and, in the most difficult cases, even 1–2 years.
This is especially true when there is infection, major bone loss, deformity, limb shortening or multiple previous surgical procedures.
The time required also depends on the technique used: revision intramedullary nailing, plate fixation and bone grafting, Masquelet, Ilizarov external fixation or bone transport all have different treatment pathways and timelines.
For this reason, in femoral nonunion it is more appropriate to speak of a personalised reconstructive pathway rather than a standard duration. The goal is not to achieve union as quickly as possible, but to obtain stable bone healing, control any infection and progressively restore limb function.
Can you return to normal walking after a femoral nonunion?
Yes. In most cases, the goal of treatment is to return to normal walking, achieving a united, stable and correctly aligned femur. Functional outcome depends, however, on the severity of the nonunion, the number of previous operations, the presence of infection or bone loss and, above all, the reconstructive technique used.
In more complex cases, some reduction in knee range of motion may persist, particularly after prolonged treatment, multiple surgical procedures or reconstructions using external fixators. For this reason, physiotherapy and preservation of joint mobility are an essential part of treatment from the earliest stages.
Modern internal reconstructive techniques may offer important functional advantages. In particular, in selected patients treated with an intramedullary bone transport nail, the absence of an external fixator during transport facilitates joint mobilisation and muscle recovery, often allowing a very high level of functional recovery and joint mobility close to normal.
The goal of femoral nonunion surgery, therefore, is not simply to achieve radiographic union: it is to restore a stable, mobile and functional limb and enable the patient to walk as normally as possible.
When should you consult a specialist centre for femoral nonunion?
A femoral fracture that is not healing requires specialist assessment particularly when pain persists over time, X-rays do not show progression of healing, or problems arise such as loosening or breakage of fixation devices, deformity, infection or bone loss.
It is especially important to consult a centre experienced in limb reconstruction surgery when the patient has already undergone one or more operations without achieving union. In these cases, the problem must be completely reassessed to determine whether the cause is mainly mechanical, biological, infectious or a combination of these factors.
The most complex nonunions may require different techniques — revision intramedullary nailing, plates and bone grafts, Masquelet, Ilizarov external fixation, bone transport or intramedullary bone transport nails — and the choice must be tailored to the individual case.
Dr. Daniele Pili specialises in the treatment of nonunions and limb reconstruction surgery, including cases associated with infection, deformity and major bone loss.
For a complete overview of the different forms of failed fracture healing and available treatment options, see the main page dedicated to the treatment of nonunions.
If a femoral fracture is not healing or previous operations have not resolved the problem, a specialist assessment can be requested. Patients should bring all X-rays and examinations performed throughout the entire course of treatment.
FAQ about femoral nonunion
I had surgery for a femoral fracture, but the femur is not healing: what can be done?
Before deciding on another operation, it is essential to understand why the fracture has not healed. Stability of the nonunion site, alignment, bone viability, any bone loss and, above all, the possible presence of infection must be assessed. Depending on the cause, treatment options may include nail revision, plate fixation, bone grafting, Masquelet, Ilizarov external fixation or, in complex bone defects, bone transport techniques.
Can a femoral nonunion heal without surgery?
It depends on the characteristics of the case and, above all, on distinguishing between a simple delayed union and a true nonunion. When the healing process has genuinely stopped, surgical treatment is frequently required to restore stability and/or biological healing capacity.
Does the intramedullary nail always have to be changed?
No. The presence of a nonunion after intramedullary nailing does not automatically mean the nail must be replaced. In some cases, revision with a larger-diameter nail is indicated; in others, it may be preferable to add a plate or change the strategy completely. Before changing the nail, the cause of the failed union must be understood.
What happens if the intramedullary nail breaks?
Breakage of the nail may be a consequence of the nonunion: if the femur does not unite, the implant continues to bear the mechanical load and may progressively fail from fatigue. In these cases, both the fixation device and the cause of failed fracture healing must be reassessed.
When is a bone graft needed?
A bone graft, frequently autologous, may be indicated when biological healing potential needs to be increased, particularly in atrophic nonunions or in the presence of certain bone defects. It is generally combined with a system capable of providing adequate mechanical stability.
Can the Ilizarov technique be used for femoral nonunion?
Yes. The Ilizarov technique is particularly useful in complex nonunions, especially when infection, deformity, shortening or bone loss are present. It allows stabilisation of the femur and, when necessary, correction of deformity or bone transport.
What happens if the femoral nonunion is infected?
The presence of infection radically changes treatment. Proper debridement of infected tissue and bone is required, the responsible microorganisms must be identified and limb stability must be maintained at the same time. In the most complex cases, Ilizarov external fixation can play a particularly important role.
How is femoral bone loss reconstructed?
This depends on the extent of the defect, the presence of infection and the condition of the limb. Options include Masquelet, bone transport with an Ilizarov external fixator and modern intramedullary bone transport nails.
What is an intramedullary bone transport nail?
It is a device that allows progressive transport of a bone segment within the femur, while simultaneously promoting new bone formation. In selected patients with major bone defects, it represents a modern alternative to traditional bone transport techniques performed with an external fixator.
How long does recovery take?
Recovery times vary widely. In simpler cases, union may be achieved in approximately 3–4 months, while infected nonunions, major bone defects and complex reconstructions may require a treatment pathway lasting one or even two years.
Can you return to normal walking after a femoral nonunion?
Yes, restoring normal or near-normal walking is one of the main goals of treatment. The outcome depends on the initial severity, the condition of the knee and hip, previous procedures and the reconstructive technique used. In complex cases, some reduction in joint mobility may persist.
When is it necessary to consult a nonunion specialist?
A specialist assessment is advisable when a femoral fracture does not show progressive healing, continues to cause pain or difficulty with weight-bearing, is associated with deformity, infection or failure of fixation devices, or when one or more previous operations have failed to achieve union.
Clinical case
Initial X-rays
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Surgery
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Healing
