A serious bone injury or fracture can sometimes leave one leg shorter than the other. This may happen when a fracture heals in a shortened position, when part of the bone is lost during a severe injury, when growth is affected, or when complications interfere with normal bone healing.
When the resulting difference is significant, limb lengthening surgery may be used to restore some or all of the lost length. In selected cases, it can also be combined with correction of a deformity or abnormal bone alignment.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Post-traumatic limb lengthening is more complex than simply making a healthy bone longer. Previous fractures, implants, scar tissue, infection, poor bone quality and damage to surrounding soft tissues can all influence the treatment plan. You can learn more about the procedure and its applications on the Limb Lengthening Surgery page.
Why Can a Fracture Make a Leg Shorter?
Several changes following a fracture can result in a shorter limb.
The bone heals in a shortened position
If the broken bone fragments overlap or shift before healing, the final bone may be shorter than it was before the injury. This is known as shortening or malunion.
Part of the bone is lost
Severe fractures, particularly high-energy or open injuries, can cause segmental bone loss. Bone may also need to be removed during treatment if it is severely damaged or infected.
The bone fails to heal normally
A fracture that does not unite properly may require multiple procedures. The resulting reconstruction can sometimes leave a persistent limb length difference.
Growth is affected
In children and adolescents, an injury involving a growth plate can interfere with further growth of the affected bone. The difference may therefore become more noticeable over time rather than appearing immediately after the injury.
When Is Limb Lengthening Considered After a Fracture?
Not every post-fracture shortening needs surgical correction. A smaller difference may be well tolerated or managed with a shoe lift or other conservative measures.
Surgery is generally considered when the discrepancy is significant enough to affect function, gait, limb balance or quality of life, or when it forms part of a more complex deformity that requires reconstruction.
The decision also depends on whether the original fracture has fully healed and whether the bone and surrounding tissues are suitable for lengthening.
In some cases, the priority is first to achieve stable bone healing and address infection or soft-tissue problems. Lengthening may then be considered as a later stage.
Can a Shortened Bone Be Lengthened After It Has Healed?
Yes. A healed bone can be surgically divided at an appropriate location and gradually lengthened using distraction osteogenesis.
The process is different from simply reopening the original fracture. The surgeon identifies a suitable level for the controlled bone cut, plans the correction and places a device that can gradually separate the bone segments.
As the segments slowly move apart, new bone forms between them. The technique can therefore be used to address shortening that remains after a fracture has healed.
What If the Bone Healed at an Angle?
A fracture may sometimes heal with abnormal angulation, rotation or translation. This is called malunion. In such cases, correcting the length alone may not be enough. The treatment plan may need to address both the shortening and the deformity.
Depending on the situation, a surgeon may perform a corrective osteotomy and then use a lengthening device to gradually restore the desired length. Modern planning may use detailed imaging to determine the location and direction of the deformity before surgery.
This means that post-traumatic limb reconstruction can sometimes involve several objectives at the same time:
- Restoring lost length
- Correcting abnormal angulation
- Correcting rotational deformity
- Restoring the mechanical axis of the limb
- Improving overall limb function
What If There Is Bone Loss After a Severe Fracture?
Severe fractures can sometimes result in a segment of missing bone. This is different from a straightforward leg length discrepancy because there may be an actual gap within the bone that needs to be reconstructed.
Distraction osteogenesis can be used in selected cases to help reconstruct significant bone defects. Depending on the injury, the surgeon may use techniques that gradually transport or lengthen bone while simultaneously addressing the defect.
Other reconstructive methods may also be considered. The choice depends on the size and location of the defect, the condition of the surrounding soft tissues, whether infection is present and the overall condition of the limb.
What If the Fracture Is Not Healing?
A fracture that has failed to unite is called a nonunion. When nonunion is accompanied by shortening or bone loss, treatment becomes more complex.
The first priority is to determine why healing has failed. Factors such as infection, inadequate stability, poor bone biology or significant bone loss may need to be addressed.
Distraction osteogenesis can be part of reconstruction in selected nonunion cases, but it is not automatically the appropriate treatment for every nonunion.
For an infected nonunion, for example, controlling the infection and removing unhealthy tissue are critical before or alongside reconstruction. The treatment strategy may therefore involve several stages rather than immediate lengthening.
Can Limb Lengthening Be Done if There Is an Infection?
Active infection is an important consideration in post-traumatic limb reconstruction. Previous infection around a fracture or implant can affect the choice of surgical technique and may increase the complexity of treatment. When infection is present, controlling the infection and establishing a healthy environment for bone healing are usually major priorities.
In selected cases, external fixation may be useful because it can provide stability without placing a new internal implant into an infected area. However, the appropriate approach depends on the individual circumstances.
A history of infection does not automatically rule out future lengthening, but it requires particularly careful assessment and planning.
What Happens if There Is Already a Metal Plate, Screw or Nail?
Previous fracture surgery is common in patients who later require limb reconstruction. An existing plate, screw or intramedullary nail may interfere with the planned lengthening procedure or may need to be removed or replaced.
The decision depends on where the implant is located, whether the fracture has healed, the planned level of bone lengthening and the stability required during reconstruction.
Imaging is particularly important in these cases because the surgeon needs to understand the existing hardware, bone shape and alignment before choosing the next step.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
How Is Post-Traumatic Limb Lengthening Planned?
Planning is one of the most important parts of treatment because a previously injured limb may have several problems at the same time. The assessment may include:
- Accurate measurement of the leg length difference
- Standing long-leg X-rays
- Assessment of bone alignment
- Evaluation of rotational deformity
- Review of previous fracture and surgical records
- Assessment of existing implants
- Evaluation of bone quality and healing
- Assessment of the skin and surrounding soft tissues
- Evaluation for current or previous infection
In more complex cases, CT-based planning may be used to better understand three-dimensional bone deformity and rotational alignment.
Which Bone Is Usually Lengthened?
The femur or tibia can be lengthened depending on where the shortening occurred and which part of the limb needs correction.
If the femur is shorter following an injury, femoral lengthening may be considered. If the shortening involves the tibia, tibial lengthening may be appropriate.
In more complex cases, both segments may be involved, although treatment is often carefully staged rather than attempting to correct every problem at once.
What Lengthening Methods Are Available After a Fracture?
The main approaches involve external fixation, internal lengthening nails, or combinations of techniques.
| Approach | How it works | Considerations after trauma |
|---|---|---|
| External fixation | A frame outside the limb gradually moves the bone segments. | Can be useful in complex deformity, bone loss or situations where internal implants are unsuitable. |
| Internal lengthening nail | An implant inside the bone gradually lengthens the limb. | May reduce problems associated with external frames, but requires suitable bone and soft-tissue conditions. |
| Combined or staged techniques | Different fixation or reconstruction methods are used at different stages. | May be considered for complex post-traumatic defects, infection or significant bone loss. |
There is no single method that is appropriate for every post-traumatic case. Previous infection, deformity, bone quality, soft-tissue condition, existing hardware and the amount of lengthening required can all influence the choice.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
How Much Can a Previously Shortened Leg Be Lengthened?
The amount of correction depends on the size of the discrepancy and the condition of the injured limb. Published studies of post-traumatic limb lengthening have reported correction of discrepancies ranging from relatively small differences to much larger defects.
In one series of 34 adults treated with internal lengthening nails for post-traumatic lower-limb discrepancies, the average preoperative discrepancy was 31 mm, with a range of 20–71 mm.
However, these figures should not be interpreted as a standard target. A previously injured bone may have different biological and mechanical characteristics from an uninjured bone, and the amount that can safely be restored depends on the individual case.
What Are the Risks of Lengthening After a Fracture?
Post-traumatic limb lengthening has many of the same risks as other lengthening procedures, but the previous injury can add further challenges. Potential complications include:
- Delayed bone healing or nonunion
- Infection
- Recurrence or persistence of deformity
- Joint stiffness or contracture
- Muscle and tendon tightness
- Nerve irritation or injury
- Problems with fixation or implants
- Refracture of newly formed bone
- Residual limb length discrepancy
- Need for additional surgery
The risk profile varies substantially according to the original injury, previous operations, infection history, amount of lengthening and reconstruction technique.
Can Lengthening and Deformity Correction Be Done Together?
Yes, in selected patients. A post-fracture limb may be both shortened and misaligned. In these situations, a treatment plan can sometimes address length and alignment together.
For example, a surgeon may correct the abnormal bone axis while gradually restoring length. The exact sequence depends on the type of deformity and the condition of the bone.
Combining corrections can make treatment more efficient in some cases, but it can also increase the technical complexity of the reconstruction.
The Bottom Line
Limb lengthening can help restore lost leg length after a fracture or other serious bone injury. It may be considered when a healed fracture leaves significant shortening, when bone loss has occurred, or when post-traumatic deformity needs to be corrected as part of a larger reconstruction.
However, post-traumatic lengthening is more than simply adding centimetres to a bone. Previous surgery, infection, bone loss, malunion, existing implants and soft-tissue damage can all influence the treatment plan.
For some patients, lengthening is performed after the original fracture has healed. In more complex cases, infection control, bone reconstruction or deformity correction may need to come first. The final treatment strategy is therefore based on the condition of the entire limb and the goal of restoring as much safe function and appropriate limb balance as possible.
