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Malunion and Nonunion Fractures

A malunion occurs when a fractured bone heals in an abnormal position, which can lead to impaired function of the bone or limb and make it look like it is ‘bent’. Similarly, a nonunion is the result of a fractured bone failing to heal after an extended period of time – in some cases over a period of 9 to 12 months.

At the Penn Orthoplastic Limb Salvage Center, orthopaedic trauma surgeons work closely with microvascular surgeons and other specialties to provide unparalleled care to correct these complex fractures.

Both types of fractures are challenging and complex and therefore, patients with suspected or diagnosed malunions or nonunions should be evaluated and treated as soon as possible.

Malunion and nonunion fractures are fundamentally different than the original fracture, and diagnosing the cause of the malunion or nonunion is important to creating the best treatment plan.

There are four main factors that Penn surgeons look for before completely treating a malunion or nonunion fracture. They include:

Infection

Malunions and nonunions caused by infection are among the most challenging to treat.

The Penn team will perform blood tests to determine if there is any infection lingering. If necessary, a local biopsy may be performed, as this will provide a much more reliable answer.

The infection must be eliminated before any reconstruction can occur.. This is a multistep process involving a round of antibiotics, debridement of all affected bone and soft tissue, any needed wound closure and removal of external fixation. This may also include removing any and all hardware that a patient might have, to remove any bacteria that could be adhered to metal and protected from antibiotics.

After the infection is treated, reconstruction can begin. At Penn, our limb salvage experts take the extra mile in preventing additional infection by applying local antibiotics to the fracture site. Penn surgeons mix bone cement with antibiotic and create a necklace of antibiotic beads which is then placed in the site. This is done to further prevent a recurrence of infection. Once infection is cleared, reconstruction of the limb can be initiated using necessary orthopaedic and orthoplastic techniques and technology.

Adequacy of blood supply

Having an adequate blood supply helps in healing a fractured limb. If Penn surgeons suspect inadequate blood supply in the bone, they will perform a CT scan or SPECT scan to confirm suspicion of dead bone.

If this is the case, the dead bone must be removed to access healthy bone and bring the ends of the living bones together. Vascularized or non-vascularized bone grafts can also be used to bridge the gap.

Depending on the amount of affected bone that must be removed, this may result in a disproportion in length. This difference in length can be addressed with Penn’s advanced limb lengthening procedures.

Biomechanics

Fractures complicate many things and impair movement. For fractures to heal properly, they need appropriate stability. Stability issues fall into two categories: hypertrophic and atrophic. Hypertrophic malunion or nonunion fractures are typically the result of inadequate fracture stability (either too little or too much support) but have strong healing potential. Atrophic malunion or nonunion fractures often have a more complicated, multifactor cause and require more complex treatment.

Penn surgeons evaluate musculoskeletal structure including alignment, healing, and the hardware used to identify type and how to address the stability issue which is dictated by location, which bone is affected, and what type of malunion has occurred.

For fractures that require dynamic stabilization like fractures of the lower thigh bone or those around other major joints, Penn uses state-of-the-art flexible screws and plates that allow for movement – providing the relative stability required for the bone to optimally heal.

Biology

A person’s biology is also an important factor for healing. As part of diagnosing complex fractures, the medical staff will perform lab tests to check thyroid levels, vitamin D, calcium, magnesium, and phosphorus levels--to name a few. Knowing these levels help physicians and surgeons understand how capable the body is to facilitate healing on its own. If there are any hormonal imbalances, specialists such as an endocrinologist will treat you before reconstruction can occur.

With these factors and their unique treatments addressed, the Penn team is able to surgically correct the fracture using tailored options and procedures including new approaches and technology being developed at Penn.

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