A1. What is bone lengthening? Download a quick time view of bone lengthening.
A2. What
is a limb length discrepancy? Limb length discrepancy (LLD)
is a measurable difference in the length of a persons limbs, either
the arms or the legs. A leg length discrepancy is more common
and troublesome than arm length discrepancy (ALD), therefore we
will confine this discussion to the legs. A small difference in
the leg lengths can have a significant functional effect on the
patient, whereas a large difference (greater than 7 cm) in the
arms is necessary to cause a problem. Arm length discrepancy can
be further reviewed in a publication entitled "Upper Extremity
Lengthening", M. T. Dahl, 1997.
Leg length discrepancy is a major problem world wide, however the exact incidence is not known. Kujala (1987) found LLD of greater than 5 mm in 51 of 141 athletes. It is difficult to quantify the amount of LLD which a patient can tolerant.
The Significance of Leg Length Discrepancy
The long term effects of LLD are poorly documented. Clinical problems can include:
Compensations for LLD
Patients with LLD walk with three basic compensation mechanisms including: pelvic tilt, vaulting (short leg equinus / toe walking), and long knee flexion. Easy fatigue is a common complaint of patients with leg length discrepancy, but oxygen consumption measurements seem unaffected in smaller discrepancies (Novacheck, Dahl l994).
Factors Affecting the Tolerance of LLD
Many features may make one patient intolerant of a LLD discrepancy that would not trouble another. Certainly, a 6 foot tall patient tolerates a 2 centimeter discrepancy with little or no trouble, while a 5 foot tall patient would be bothered by the same discrepancy. Children, with their inherent flexibility, tolerate discrepancies better than adults. A rapid onset discrepancy also influences its tolerance. For example, a previously normal adult who suddenly develops a 5 centimeter discrepancy from an accident, doesn’t compensate as well as if the discrepancy had been there since childhood. Finally, patients with additional problems, such as joint contractures, arthritis, joint replacement, joint fusion, malalignment, and spasticity all have limited ability to compensate for a discrepancy.
Causes of Leg Length Discrepancy
Fractures can increase the length of the lower extremity in growing children. This occurs when growth plates are stimulated from the increased blood supply, brought in for fracture repair. This phenomenon, called "overgrowth" rarely exceeds 3 centimeters, making it a condition well suited to treatment by epiphyseodesis (growth plate arrest)
Fractures involving the growth plates can cause shortening, as the fracture site may damage the growth cells of a child.
Limb length discrepancy is a common manifestation of congenital and acquired conditions of childhood, with the major causes listed in table 1, and classified as to causing shortness or overgrowth of the limb.
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| Congenital |
Femoral deficiencies Congenital coxa vara Congenital deficiencies of the leg i) posteromedial bowing of the tibia ii) fibular hemimelia iii) tibial hemimelia iv) congenital pseudarthrosis of the tibia Neurofibromatosis |
Anisomelia (hemihypertrophy and hemiatrophy) i) Russell-Silver syndrome ii) Klippel-Trenauny-Weber syndrome Vascular malformations |
| Trauma |
Overriding fractures Epiphyseal fractures causing growth plate damage |
Healing fractures causing overstimulation |
| Infection |
Osteomyelitis causing growth plate damage Septic arthritis |
Osteomyelitis causing overstimulation |
| Neurologic |
Cerebral palsy Myelodysplasia Poliomyelitis |
|
| Tumors or dysplasias |
Malignant tumors Multiple exostosis Fibrous dysplasia Ollier’s disease |
Hemangiomata |
| Inflammatory |
Rheumatoid arthritis Hemophilia |
Rheumatoid arthritis or hemophilia causing overstimulation |
The causes of post traumatic shortening include:
1) Premature asymmetric growth plate arrest.
a)Transphyseal fractures can result in deformities of length and angulation, the magnitude of which is dependent on the patients’ skeletal age, growth plate involved, and type of fracture.
b) Iatrogenic. Traction pins, K-wires and screws that cross the growth plate can cause growth arrest.
c) Inflammatory. Osgood-Schlatter’s may be a predisposing factor to asymmetric growth arrest of the tibial tuberosity.
2) Malreduction. Bayoneting of fracture fragments in pediatric femoral shaft fractures, relying on overgrowth to compensate, is a common cause of malunion. Prior to the age of intramedullary nailing, balanced skeletal traction was the standard of care for femoral shaft fractures. This time-intensive treatment requires attentiveness and skill, yet often results in malreductions of angulation of 10 - 30 degrees, and shortening of 2 - 5 centimeters.
3) Trauma and lost reduction. Severe fractures can result in shortening if the healing is slow and the fragments collapse. Failure of internal fixation (rods or plates) is another cause.
4) Segmental bone loss can result in collapse of the defect and nonunion/malunion with shortening, or it can result in nonunion with or without limb shortening.
5) Resection. Nonunions are often dealt with surgically by resecting the nonunion and internal fixation. This can lead to shortening of the bone. If reoperation is necessary, further shortening results.
A3. Who is a
candidate for bone lengthening?
Indications for Treatment of Limb Length Discrepancy (LLD)
Most patients of normal height with LLD of less than 2 cm are minimally symptomatic. Surgical treatment is indicated for discrepancies above 2.5 centimeters (one inch).
Bone shortenings, either growth plate arrest in the growing child, or femoral shortening in the adult, are considered appropriate for discrepancies from 2.5 to 6 centimeters. Tibial shortening is a dangerous operation because of compartmental anatomy, and difficulties in wound closure, and is also very disfiguring because of distortion of the leg profile.
Bone lengthening is appropriate for discrepancies between 3 and 10-15 centimeters, however the upper limits have been changing as we refine the methods of distraction osteogenesis. Bone has excellent capacity for regeneration, but the soft tissues (ligaments, tendons, muscles) resist stretching, and joint surfaces don’t tolerate massive lengthenings (> 15%). These soft tissue problems continue to limit safe lengthenings, particularly in the congenitally short limb.
Treatment guidelines for LLD:
| 0 - 2 cm | none |
| 2 - 6 cm | lift, shortening, or lengthening |
| 3-10 cm | lengthening |
| 8-15 cm | lengthening or combining lengthening and shortening |
| > 15 cm | amputation, prosthetics, lengthening, combinations |
(These guidelines are highly individual.)
A4. What
is a congenital limb deficiency? Congenital limb deficiency
is a term used for a condition, present at birth, that results
in shortening, deformity, or dysfunction of the limb. There is
commonly present, additional deformities or deficiencies of the
surrounding tendons, muscles and joints.
A5. What
is a growth plate injury? Growth plates are disc shaped
areas of a specialized cartilage located near the ends of bones
in the growing child. When we stop growing taller (about age 14
in girls and age 16 in boys) the growth plates seal with bone
and cease to add length to the bone. A fracture which occurs through
the growth plate may cause it to fuse prematurely, resulting in
a limb length discrepancy. The younger the child at the time of
the injury, the greater the shortening that may result.
A6. What
are the alternatives to bone lengthening? A
wide variety of treatment options exist for the patient with a
limb length discrepancy. The simplest form of treatment doesn’t
involve surgery.
Shoe Lift. A sole or heel lift can be attached to or inserted inside the shoe and can effectively level a difference of one to five centimeters. Beyond this, the lift gets heavy, awkward, and can cause problems such as ankle sprains and falls.
Shortening the long side. On the surface, this may sound
illogical and even dangerous, but bone shortening can be a simple,
safe and effective way of equalizing leg lengths.
Limb shortening can be accomplished in one of two ways: 1) The physeal growth centers (growth plates) can be arrested prematurely by epiphyseodesis. 2) The long bone can be shortened by resecting a segment of the bone.
Epiphyseodesis (growth plate arrest)
This is the simplest surgical method of equalizing leg lengths. The procedure was originally described by Phemister in l933 (JBJS 15:1 1933). The original technique required large incisions with considerable dissection and morbidity for the child. In recent years (Canale, Dahl), techniques of percutaneous arrest have replaced Phemister’s method, allowing outpatient surgery with little risk or pain. Under light general anesthesia, a tiny incision is made next to the growth plate which is then drilled under x-ray guidance. Recovery is rapid, with little pain. Crutches are usually not needed. Sports are avoided for 2 -3 months while the drill hole fills in with bone, resulting in stoppage of growth at the growth plate. Growth continues normally elsewhere in the leg, and the legs gradually reach equal length at maturity. The greatest problem with epiphyseodesis is the difficulty in choosing the proper timing of surgery. This procedure is most commonly performed at age 11 or 12 in girls, and at age 13-14 in boys.
Bone Shortening (resection)
Surgically removing a segment of the longer bone is done for those patients who are not candidates for lengthening, who do not wish to undergo lengthening, or for those that are skeletally too old for epiphyseodesis (adults). Performing surgery on the "well-leg" is objectionable to some patients, but in experienced hands, shortening the longer bone poses low risk to the limb. This is a much larger operation than growth plate arrest, requiring several days to recover in the hospital, and 4 -6 weeks on crutches. Shortening the femur is safer than shortening the tibia. Femoral shortening is accomplished by a closed shaft resection with intramedullary rod fixation or an open resection with plate fixation.
A7. What
is an external fixator?
External fixation has been used for the treatment of bone injury since the early 1900s. 20 to 30 years ago, external fixators began to compliment other systems of fracture repair (plates, rods, and screws), but they developed a reputation for requiring extra effort, having the risk of delaying healing, and the potential for pin site infection. During the past fifteen years, circular external fixation has met with success in the treatment of congenital, developmental, and post-traumatic orthopedic conditions. The original Ilizarov external fixator consists of stainless steel rings, connected by threaded rods. 1) Each ring is attached to the underlying bone segment by 2 or more wires, placed under tension to increase stability, yet maintain axial micromotion. Titanium pins are also used for supporting the bone segments. A large variety of external fixators are now available for use. Today’s fixators are very durable, and are generally capable of holding full weight. Most patients can continue many normal activities during the three to six months the device is worn.
A8. How long
does bone lengthening take?
The Process of Limb Lengthening
Limb lengthening duration is variable and dependent on many factors. Generally, a bone lengthening requires wearing the external fixator four to six months; four to six weeks for correction, and three to four times that for bone maturation. Limb lengthening and deformity correction is not a procedure, rather it can be considered a process, occurring and changing over weeks and months. Using external fixation as a method of treatment requires a surgeon with a certain personality, one willing to invest the planning and preoperative education time, patience in the operating room, and persistent postoperative care. It requires a special patient’s personality, too, a willingness to focus attention to the details of physical therapy and functional use of the limb while the correction is occurring. Patients with severe problems have often endured long, painful and unsuccessful treatment by the time they need to consider a correction such as bone lengthening, straightening, or non-union reconstruction. It requires great patience and determination to further endure such lengthy treatment.
Planning
Planning starts with a comprehensive evaluation of the problem, with particular attention to the cause, orthopaedic history, and overall health of the patient.
For elective reconstructions such as limb lengthening, it is helpful for the surgeon and patient to visit on several occasions to carefully analyze the problems and address all the issues associated with the correction. Treatment becomes a collaboration with the patient and physician, requiring strict compliance during the often prolonged treatment. Preoperative patient education builds the foundation for this collaboration. In the acute trauma setting, when urgent surgery is necessary, preoperative education is replaced with perioperative education.
Problem list
Ilizarov suggested the creation of a problem list, which consists of a detailed compilation of the patient’s current abnormalities and those that may arise with correction or future growth. This list combines features such as: the length discrepancy, the plane and magnitude of angulation. Other deformity features may include: translation, rotation, bone loss and contracture or joint instability. The patient’s age, cause of deformity, neurovascular and psychological status and the condition of the soft tissues are also considered. Once complete, the list is manually written on an overlay tracing of the x-ray, which is used as a worksheet.
Designing fixation
The plane, magnitude, and apex of the deformity are measured. Depending on the extent of deformity, correction desired, and the size of the bones; a uniplanar fixator or a circular fixator may be used. When lengthening is not necessary, conventional surgical techniques using internal fixation are used. A uniplanar fixator may be selected when no angular deformity exists or when angulation can be safely performed intraoperatively, followed in 7 - 10 days by gradual lengthening. The circular fixator is used in most cases that require gradual, multisite, or particularly complex corrections.
Fixator rings are drawn onto the deformed bone segments on the work sheet. Hinges, connecting rods, and motor rods are drawn in place based on the deformity. The worksheet is cut with a scissors at the proposed corticotomy site and the segments are angulated into the desired position through the hinge sites, thereby testing the correction plan. Pin and wire locations are preoperatively selected and drawn on the worksheet.
Computer graphics can be alternatively used in selected cases.
The fixator is assembled to match the specifications arrived at during planning, and final adjustments are made during a preoperative fitting session. This fitting provides for further preoperative education and allows the patient to become familiar with the device. In cases of acute trauma applications, such as in tibial plateau or pilon fractures, a preoperative CT scan is essential. The surgical approach and position of interfragmental bone screws is made on the basis of this scan.
The surgical procedure. The specifics of surgery will be governed by the individual’s particular needs. The fixator is attached to the limb under general anesthesia in an operation lasting one to three hours. The devise is secured with a combination of thin stainless steel wires and thicker titanium pins. The patient is encouraged to be active promptly after surgery. Generally, full weight bearing with the aid of crutches is encouraged from day one.
The hospital stay is surprisingly brief. As the patient’s are well educated preoperatively, there is rarely a reason for a prolonged hospital stay. Most patients would prefer early discharge, knowing that the MLLC staff is available to help at any time.
Clinic visits occur weekly during distraction and monthly while the bone is maturing.
A9. How much
does it hurt? The patients’ perspective.
A10. Does insurance
cover this surgery? The methods used at the MLLC are now well
recognized by orthopaedic surgeons world-wide, but insurance companies
often need education as to the effectiveness and results, as the
methods have only been used in the U.S for ten years. Once a clear
description of the necessity of the surgery is received, the insurance
companies provide coverage.
A11. Is
there a team to help me through the lengthening
process? We long ago learned to teach and employ specialized
staff for these specialized treatments. Our Limb Length nurse
at each clinic location, Gillette Children’s and Fairview-University
Hospitals, have greater experience with these conditions than
any nurses in the upper Midwest. With nearly 1,000 corrections
now completed, much can be said for this type of specialization.
The operating room staff, ward nurses, physical therapists, orthotics,
and x-ray staff also have developed great experience in their
respective areas.
A12. What
is a non-union? A non-union is a fracture or defect
of a bone induced by disease, trauma, or surgery that fails to
heal within a reasonable time span. This time varies considerably
based on the bone involved, location and severity of the injury,
age and health of the patient, and the success of any surgery
that has been performed. Healing guidelines are difficult to define
because of the varied intrinsic and extrinsic factors that are
further affected by treatment. The United States Food and Drug
Administration established nine months as an appropriate duration
of healing before one can consider the fracture a non-union. A
more practical diagnosis of delayed union or non-union can be
a fracture that shows no progressive x-ray and clinical signs
of healing in a time frame appropriate to the fracture and its
location. It is important to recognize delayed healing early so
that treatment is instituted promptly to prevent non-unions.
A13. Why isn’t my bone healing? A wide assortment of factors can delay bone healing. The most common, of course, is the severity of the original injury and the extent to which the bone’s surrounding blood supply was damaged. These factors are beyond the control of the surgeon or patient, once the injury occurs. A fracture generally needs three features to adequately heal:
A14. Who should
I call for help? To schedule an appointment
A15. What
can be done for my knee arthritis? Premature wearing of
knee cartilage may result in arthritis in the younger adult. In
instances where deformity exists, realignment may be beneficial
in delaying the progression of arthritis.
A16. What
is an osteotomy? Osteotomy means simply "bone cut".
The osteotomy frequently used for knee arthritis is known as High
Tibial Osteotomy, or Proximal Tibial Osteotomy. It can be done
in one of several ways, depending on severity, location, ligamentous
laxity, and several other features. It is generally performed
for the individual with arthritis of the medial compartment, too
extensive for arthroscopy, and too young for knee replacement.
Pain relief lasts for 5-20 years after the osteotomy, which may
then be followed by knee replacement.
A17. Why
Minnesota? Minnesota, Land of 10,000 Lakes is noted for
its excellent hospitals, doctors, and nurses. The relatively sparse
population in the upper Midwest and the extremes in climate, combine
to encourage a civility not usually found in larger cities.
A18. Where
do I stay? Visitors to the Fairview-University clinic in
Minneapolis can stay at one of several clean, comfortable, and
affordable hotels or longer term rental units. Below are a few
hotels listed for your convienence:
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MINNEAPOLIS Radisson Hotel University |
ST. PAUL Best Western Kelly Inn |