External Fixation

External fixation is a technique in which an apparatus is mounted to the outside of the body.  The two types of external fixators that are used in limb lengthening are either

  • a monolateral fixator in which the fixator is mounted to only one side of the limb (typically the femur and humerus)
  • a circular external fixator, in which the fixator or "frame" is mounted around the limb.  Frames may be placed on any limb, with the most typical being the tibia (leg), femur (thigh), humerus (arm), or the forearm

MONOLATERAL FIXATOR - Monolateral fixators are only on one side of the limb - typically the outer thigh or arm, or the inner leg.   Sometimes they are used to treat broken bones - especially if the bone is very comminuted (in many pieces) or the skin is badly damaged.  In limb lengthening, they are used at times when all that is needed is pure length.  They are generally well tolerated.  Dressing around the external fixator can sometimes be challenging (especially if it is on the femur), but your COA surgeon can help guide you and your child through the process. 

For any type of fixator, either monolateral or circular, the "frame" is mounted to the body by placing special pins or wires through the skin and then inside the bone.  There is a special coating called hydroxyapetite that is on the half pins to allow them to stick to the bone better.  This decreases but does not eliminate the risk of pin tract infections.  Pin infections are common, but are typically preventable.  It is extremely important that the pins are cleaned once or twice per day.  Please click here for more information about pin cleaning.

Prior to the external fixator being removed, your doctor will often require your child to be walking without any limitations.  The fixators are removed in the operating room under general anesthesia.  Your doctor may either place your child in a walking cast for a short period of time once the fixator is removed or require crutches for 3-4 weeks, until the bone is stronger.

 

CIRCULAR EXTERNAL FIXATOR - Circular fixators, as implied, is mounted completely around the limb.  The first circular fixator was the Ilizarov fixator which has been utilized since the 1950's. However, over the past 30 years, the Ilizarov has been replaced with more advanced circular fixators that are designed on a hexapod platform that is integrated with computer software to   assist in both lengthening a bone as well as correcting any type of deformity. 

The first type of this new generation of external fixators is the Taylor Spatial Frame, which is manufactured by Smith and Nephew (Memphis, TN). The spatial frame is typically made of at least two carbon fiber or aluminum rings connected together by 6 struts in a hexapod configuration.  An additional circular external fixator device is also FDA approved for deformity correction in the United States.  It is known as the TL Hex Frame (manufactured by Orthofix in Lewisville, TX).  While the results can be dramatic, only orthopedic surgeons who have been specially trained in limb deformity and limb lengthening should use such a device. Several of the COA surgeons have received such training.

A child in an external fixator, especially when undergoing a limb lengthening and/or deformity correction is truly a family affair.  Your child will likely require weekly doctor visits, multiple adjustments to the frame on a daily basis, trips to physical therapy, assistance with using crutches to get around the house, etc.  A treatment such as this one is a large undertaking, and therefore, requires careful planning and extensive communication to make such a treatment successful.

While the process is burdensome, the results are truly life-changing.  Within this COA practice, children have gone from being handicapped and/or in constant pain from crooked and/or short limbs, to walking pain free with straight, even legs. 

Prior to the external fixator being removed, your doctor will often require your child to be walking without any limitations.  The fixators are removed in the operating room under general anesthesia.  Your doctor may either place your child in a walking cast for a short period of time once the fixator is removed or require crutches for 3-4 weeks, until the bone is stronger.

  • To learn more about life with a Taylor Spatial Frame click here.  
  • To learn more about llife with a TL Hex Frame Frame click here.

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