Bone Lengthening:  All You Need to Know

Bone lengthening is a procedure to lengthen the bones in the arms or legs. It is a gradual process to slowly promote the length of bones and soft tissues such as skin, nerves and muscles. More often than not this process takes several months if performed with utmost care. Limb lengthening can also be combined with gradual or acute deformity correction.

How does the process work?

The doctor creates an incision in the bone during the surgery to create two separate bone segments. This process of cutting the bone is called osteotomy. Apart from this any additional soft-tissue procedures might be added and performed along with osteotomy to prepare the nerves and muscles for the lengthening.  For instance, surgically lengthening of the Achilles tendon may be done to make a tibial (shin bone) lengthening go easier. The doctor will then attach an orthopaedic lengthening device to the bone. These orthopaedic devices can either be internal (such as precise nail) or external fixators (such as Ilizarov device)

Different phases of surgery:

Latency phase

The period after your surgery where the bones are allowed to heal for 5-7 days is called the latency phase.

Distraction phase

The period followed by the latency phase where the gradual process of separating the bone begins is known as the distraction phase. As the hollow between the two bones increases, the formation of a new bone in between them begins which will thus increase the overall length of the bone. This bone is called the regenerate bone.

Amid the distraction phase, the bones are slowly pulled apart and the device is gradually adjusted by the family members of the patient.

Consolidation phase

The distraction phase is then followed by the consolidation phase where the regenerated bone starts to harden. The new bone will not be “healed” until the regenerate bone has hardened and calcified. To help the bone heal, patients should avoid nicotine in any form, eat a healthy diet with lots of protein and take vitamin and mineral supplements. The doctor would further advice putting some weight on the bone to expedite the hardening process.

Types of Orthopaedic Devices:

External Fixators– External fixators are metal devices that are attached to the bones with threaded pins and wires. These pins or wires pass through the skin and are inserted into the bone. Since the whole thing is outside the body, it is called an external fixator. Many people only require one external fixator to be applied, but some will need two or more external fixators. External fixators can usually be divided into dichotomies and they are: circular fixators and monolateral external fixator.

Circular fixators are fixators that completely or partially cover the bone that needs the lengthening. It is shaped like a sphere which is connected with various struts, wires and pins.

The TSF, Taylor Spatial Frame is a type of circular fixator that consists of two rings that are usually connected by six struts. The TSF is usually used to correct angular and rotational deformities.

Ilizarov external fixators originally called the circular ring fixator are another type where the patient or the family member uses a small wrench to adjust the device several times in a day. This type of fixator is usually used on small children.

Internal Fixators- Internal bone lengthening is when the device used to lengthen the bone is inserted inside the bone

Precice Lengthening- the lengthening device has a small magnetic motor inside it. When the motor is activated by an External Remote Controller (ERC), the device slowly lengthens, and this causes the bone to slowly lengthen. The process is so slow and gradual that usually people don’t even feel any discomfort or pain.

Rods and Nails– also known as the intramedullary device are cylinders that are made of surgical grade metal that is inserted the marrow cavity of a long bone (femur, humerus etc.). Nails and rods are both inserted into the center of the bone, but only nails are attached to the bone with cross bolts or locking screws. It is pertinent to note that the rods and nails attached will affect the marrow but will not affect the ability of generating red blood cells.

Plate– this is an internal fixator where a plate with a help of screws are inserted between your bones. Plates can either be removed or not depending upon the doctor’s suggestion. Keeping the plate in place can help you prevent nonunion and malunion (bone cut not healing and the bone cut getting crooked respectively).

Understanding the speed:

One of the biggest issues with this procedure could either be healing of the bone that is either too fast or too slow. Some people’s bones heal very quickly, and the regenerated bone may harden before treatment is completed. This is called premature consolidation. In the case of premature consolidation another quick surgery needs to be performed in order to remove the hardened bone so that the lengthening process can continue.

Even though the typical rate of lengthening is 1 mm per day, some people might take more time for instance people with diabetes or smoking issues might find their bone healing at a very slow pace. In such scenarios usually the doctor keeps a constant check on the patient during the distraction phase and in case he notices some discrepancy then he adjusts the device to a shorter amount.

Outcome of the surgery:

Usually, the bone can be lengthened up to 2 inches (5cm) in each bone. However, this depends on a case to case basis and there are people who can easily go beyond 2 inches. Two different types of lengthening can be done on the shin and thigh bone at the same time to increase the total lengthening procedure to 4 inches in each leg.  Often, patients undergo several cycles of lengthening over the course of several years, depending on their age, stage of growth, and amount of lengthening needed.

Risks involved:

There are some serious risks involved when it comes to lengthening procedures and they include:

• nerve damage
• muscle damage
• joint contracture
• dislocations
• arthritis

Keeping these risks in mind, it is important to weigh all your options and choose a clinic that puts your child’s needs first. At Young Bones Clinic, we understand what the patients and their families want. We strive to ensure that our patients firmly understand the outcome of the surgery along with all the possible risks involved so that they can make a prudent decision for themselves or their children.