Percutaneous Distal Femoral or Proximal Tibial Epiphysiodesis for Leg Length Discrepancy

 

 

 

 

DEFINITION

Epiphysiodesis involves manipulation of a physis (growth plate) to cause temporary or permanent, partial or complete growth inhibition to correct length or angular deformity in children with growth remaining.

In the setting of leg length discrepancy, epiphysiodesis must cause growth inhibition symmetrically across the physis such that shortening results without development of angular deformity.

Epiphysiodesis can be achieved by obliteration of the growth cells through physical disruption (drill, curettage, radioablation, or similar) or tethering with various devices (screws crossing the physis or staples/small plates at the periphery of the physis) or various forms of bone grafting such as the open

Phemister technique.22

Today, the two most common techniques are percutaneous drill and percutaneous screw epiphysiodesis.7

Growth of the longer extremity is inhibited by prematurely arresting or tethering growth at one or more physes so that remaining growth of the shorter extremity may “catch up” thus approximating limb lengths at maturity.

Patients with a predicted leg length discrepancy of less than 2 to 2.5 cm do not typically require surgical intervention and may be treated with observation or a shoe lift/insert.

Epiphysiodesis is usually considered when the final limb length discrepancy of the lower extremity is predicted to be in the range of 2 to 5 cm. Patients with leg length discrepancies greater than 5 cm may be considered for other procedures, including lengthening. Some patients with large discrepancies may undergo lengthening on their short side, as well as epiphysiodesis on their long side, to minimize the number of lengthening procedures required.

Limb equalization surgery is considered successful if residual leg length discrepancy is less than 2 cm.

In order to optimize leg length equalization, the surgeon must understand the etiology of the leg length discrepancy and be able to predict growth based on the underlying cause of growth inequality, the child's maturity by chronologic and bone age, and the child's own height percentile and parental and sibling heights.

 

ANATOMY

 

The physis is made up of cartilage cells that are replicating and growing away from the physis.

 

 

The germinal cells are on the epiphyseal side of the physis.

 

 

The distal femoral physis and proximal tibial physes are undulating and slightly curved. The neurovascular bundle is posterior and midline at the level of the distal femoral physis.

 

The common peroneal nerve at the knee runs obliquely along the lateral side of the popliteal fossa, close to the medial border of the biceps femoris muscle and the lateral head of the gastrocnemius muscle, toward the head of the fibula.

 

 

The nerve winds posteriorly around the neck of the proximal fibula and passes deep to the peroneus longus muscle, where it divides into the superficial and deep peroneal nerves.

 

EPIDEMIOLOGY

 

Approximately 25% of people have a leg length discrepancy of 1 cm or more, and the incidence of leg length discrepancy of 2 cm or greater is estimated at 1 in 1000 cases.

 

Epiphysiodesis is the most frequently used operative procedure in North America for the equalization of limb lengths.

 

PATHOGENESIS

 

The etiology of a limb length discrepancy can be congenital/developmental; related to tumor; neuromuscular disease; skeletal dysplasia; or otherwise acquired through trauma, infection radiation, or other causes. A partial list of causes includes the following:

 

 

Congenital shortening: proximal focal femoral deficiency, coxa vara, congenital short femur, fibular and tibial hemimelia, hemiatrophy

 

Congenital lengthening: overgrowth syndromes such as hemihypertrophy, Beckwith-Wiedemann syndrome, Klippel-Trenaunay-Weber syndrome, and Parkes-Weber syndrome

 

Skeletal dysplasia or tumor: Multiple hereditary exostoses may result in limb shortening on the affected side, as growth cartilage cells are diverted to the cartilage tumor. Radiation for malignancies adjacent to the physis may result in growth suppression or complete destruction of physeal cartilage cells, resulting in limb length discrepancy or angular deformity.

 

Infection: Physeal destruction may result from physeal invasion from adjacent metaphyseal or epiphyseal bacterial osteomyelitis or direct physeal involvement in the case of intracapsular joint physes such as at the hip and shoulder.

 

Paralysis: Poliomyelitis and cerebral palsy as well as other nervous system afflictions in children typically result in shortening on the more affected side.

 

Trauma: direct injury to growth plate, posttraumatic bone loss or shortening, and overgrowth following femoral fracture

 

Miscellaneous: slipped capital femoral epiphysis, Legg-Calvé-Perthes disease

 

 

 

NATURAL HISTORY

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Depending on the underlying cause of the leg length discrepancy, a discrepancy may be static or increase or decrease with remaining growth.

 

 

Congenital limb length discrepancies typically maintain proportional growth over time. For instance, a tibia that is 10% shorter than the normal side at birth will be approximately 10% shorter than the normal side at maturity.

 

Leg length discrepancies under 2 cm are typically well tolerated.

 

Untreated leg length discrepancy of more than 3 cm may result in pelvic obliquity, visual gait disturbance, short-legged gait, or structural/nonstructural scoliosis.

 

Leg length discrepancy greater than 5.5% of the long leg has been shown to decrease the efficiency of gait, as determined from kinetic data.23

 

No causative relationship has been proved between leg length discrepancy and knee or hip pain or arthritis. A large population study has shown an association between leg length discrepancy and knee arthritis, but there

was no evidence of causation.9

 

Although scoliosis has been associated with leg length discrepancy, there is no evidence that leg length discrepancy causes structural curvature of the spine. Assessing the spine with a block under the short leg, with the pelvis level, permits assessment of true scoliosis.

 

Following drill epiphysiodesis, bony bridges form between the epiphysis and the metaphysis, preventing further physeal growth. Growth arrest has been documented within 3 months of the procedure using

radiostereotactic (RSA) three-dimensional imaging.11

 

Following screw epiphysiodesis, there is compression or tethering across the physis. Physeal closure may be slightly delayed compared to ablative techniques. Growth inhibition has been documented within 6 months of screw epiphysiodesis but has not been measured using RSA or other highly accurate techniques.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

The underlying cause of a leg length discrepancy can typically be elucidated by careful history and physical examination.

 

The common symptoms at presentation are limp, compensatory gait mechanics, pelvic obliquity, and nonstructural scoliosis.

 

Physical findings depend on the etiologic factors.

 

In hemihypertrophy (both syndromic and nonsyndromic), the affected extremity may be larger in both length and girth. In classic hemihypertrophy, upper extremity hypertrophy as well as hemifacial asymmetry may be present. Vascular overgrowth syndromes may be associated with cutaneous or deep hemangiomas, which may alter surgical approaches to attempted limb equalization.

 

Clinically, leg length discrepancy is best measured by the block test, in which the shorter leg is placed on increasingly larger measured blocks until the posterior iliac crest is level. Discrepancies as small as 2 cm are accurately detected by this method, and detection of discrepancies is largely unaffected by patient size or body mass.

 

True leg length is measured from the anterior superior iliac spine to the tip of the medial malleolus. It is important to place the legs in identical positions to measure true leg length, and for this reason, this measurement is less accurate than the block test.

 

 

If the patient has a 20-degree abduction deformity of right hip, the left hip is placed in 20 degrees of abduction to measure true length.

 

Apparent leg length is measured with the patient supine with the legs parallel to each other. The landmarks are the umbilicus to the tip of medial malleolus. Pelvic obliquity and fixed deformities of the hip and knee affect the reading. This method is also significantly less accurate than block measurement.

 

Range of motion is noted for all joints, primarily the hip, knee, ankle, and subtalar joints. The ankle joint range of motion is measured with the knee in extension and flexion.

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain radiographs have traditionally been used to document the objective measurement of leg length discrepancy.

 

Full-length (hip to ankle) anteroposterior (AP) radiographs are obtained in standing position with both patellae facing directly anteriorly. The appropriate-sized block is placed beneath the shorter leg to level the pelvis. A long x-ray cassette (51-inch) is used with the x-ray beam center focused on the knee from a distance of 10 feet. A radiolucent ruler often is used to assist in calculation of limb discrepancies.

 

 

A lateral hip to ankle view can be included to further assess length, as contractures in the sagittal plane may result in inaccuracies on AP measurements. This view can also assess for angular deformities in the coronal plane.

 

Computed tomography (CT) scanogram has been the gold standard for low-dose accurate imaging of leg length discrepancy.

 

CT scanogram is as precise in measuring leg length discrepancy as the slit scanogram and it has the added benefit of more easily measuring leg length discrepancy in the setting of joint contractures. Slit scanogram is of historical interest only and is no longer typically used for measuring leg length discrepancy.

 

EOS8 is a low-dose, high-resolution radiologic imaging system that captures standing simultaneous posteroanterior (PA) and lateral radiographs and full-body radiographs.17

 

Recently, EOS biplanar imaging systems have been shown to be equally accurate/reliable with the added benefit of imaging the patient in a standing position such that leg length and alignment can be obtained from

a single low-dose image. Radiation exposure is also lower with EOS.6

 

Skeletal age can be determined by a left hand/wrist radiograph in combination with the Greulich and Pyle method.10

 

Alternatively, the Hospital for Special Surgery (HSS) shorthand method can be used. This method was derived from Greulich and Pyle and uses a single radiographic criteria is used for each age, allowing for rapid bone age determination.12

 

 

The leg length discrepancy at maturity can be predicted in a variety of ways: The arithmetic method18

 

The growth remaining method1, 2

 

 

The Moseley straight line method20 The Paley multiplier technique21

 

Applications/programs that incorporate the Paley multiplication factors are readily available on smartphones/computers for clinical use. These allow calculation of length

 

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discrepancy at maturity for both congenital and acquired deformities.

 

 

Parental and sibling height may be useful in interpreting predicted height be the above methods.

 

In leg length discrepancy secondary to physeal growth arrest, graphical or arithmetic methods are helpful in determining appropriate timing of epiphysiodesis.

DIFFERENTIAL DIAGNOSIS

True shortening (eg, femoral or tibial) Apparent shortening due to dislocated hip Apparent shortening from contractures Angular deformity causing apparent shortening

Overgrowth syndrome with both increased length and limb girth: hemihypertrophy Congenital limb deficiency

Trauma, radiation, tumor, infection, burns, and other causes.

 

 

NONOPERATIVE MANAGEMENT

 

 

No treatment is required for a predicted limb length discrepancy of less than to 2.5 cm at maturity. A shoe lift can be used as treatment for leg length discrepancies at maturity below 2 cm.

 

Often, a lift is used in children until an appropriate skeletal age is reached to perform an equalization procedure.

 

SURGICAL MANAGEMENT

 

Epiphysiodesis is most commonly performed at the distal femoral physis or the proximal tibia with or without fibular physis.

 

Ablation of the medial and lateral physis causes bony bridges to form between the epiphysis and metaphysis that accomplish growth inhibition in that physis (epiphysiodesis).

 

 

This can be accomplished by different instruments, including a curette, a drill, a burr, a reamer, or radioablation.

 

Some authors recommend ablation only at the periphery, as bony bridge formation at the peripheral margins of the physis both medially and laterally has been shown to cause spontaneous closure of the central physis.

 

The authors' preferred method for mechanical ablation involves ablating the majority of the physis, including the central portion.

 

 

Due to intact cortex at the physis (with the exception of two small drill holes), stability of the bone is maintained postoperatively and the patient may weight bear as tolerated, although traditionally, the child is protected with a brace and crutches for the first few weeks.

 

There is no clear evidence to support when a child should return to sports, although given the potential destabilizing effect of disruption the physis and theoretical concern for Salter Harris fracture, it is reasonable to delay return to sports for the first 6 weeks following mechanical ablation of the physis.

 

 

Transphyseal screws are another option for longitudinal growth inhibition. This technique tethers the physis causing growth inhibition.

 

Preoperative Planning

 

Anticipated remaining growth is determined by obtaining bone age and using one of the prediction methods

mentioned earlier.

 

A proximal fibular epiphysiodesis should be performed in addition to the proximal tibial epiphysiodesis if the final discrepancy between the tibia and fibula is anticipated to be more than 2 cm.

 

 

 

No method is completely accurate, with an error for each method of up to 1.5 cm. The authors' preference is to use the multiplier method.

 

Charts are available for both acquired and congenital leg length discrepancies, and predicted growth can be easily calculated with a calculator or a multiplier specific software program or smartphone application.

 

Some studies suggest that growth inhibition with screw epiphysiodesis may be less than with drill/curettage, although this has not been the authors experience.15

Positioning

 

For both drill/curette and screw epiphysiodesis, the patient is placed supine on a radiolucent table.

 

 

A bump below the hip on the operative side may aid in maintaining the patella forward.

 

A tourniquet is placed on the proximal thigh but is not inflated unless bleeding occurs.

 

 

Elevating the operative leg on a bump or wedge will help facilitate lateral fluoroscopy and passage of wires/drills/screws from both the medial and lateral starting points (FIG 1).

 

Fluoroscopy can be brought in from the patient's nonoperative side.

 

Approach

 

Drill/curette

 

 

Distal femoral epiphysiodesis

 

 

Longitudinal incisions of 5 mm medially and laterally are made in the skin at the level of the physis.

 

Proximal tibial epiphysiodesis

 

 

Longitudinal incisions of 5 mm medially and laterally are made in the skin at the level of the physis, with the lateral incision just anterior to the fibular head.

 

Proximal fibular epiphysiodesis

 

 

 

The same incision is used for the fibular epiphysiodesis as for the lateral physeal area of the tibia; however, in the epiphysiodesis of the fibula, the drill and curette

 

enter at the anterior/superior aspect of the fibula and longitudinally cross the physis.

 

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FIG 1 • The patient is placed supine on a radiolucent table, with the operative leg elevated on a bump or wedge for ease of AP and lateral fluoroscopy, and passage of instruments from both medial and lateral starting points, across the physis.

 

 

Screw

 

 

Distal femoral epiphysiodesis

 

 

Longitudinal incisions of 8 mm are made medially and laterally proximal to the physis by approximately 4 to 6 cm.

 

Proximal tibial epiphysiodesis

 

 

Longitudinal incisions of 8 mm are made medially and laterally distal to the physis by approximately 4 to 6 cm.

 

The incision for the lateral screw is made just lateral to the tibial crest, and the anterior compartment muscles are retracted laterally.

 

 

TECHNIQUES

• Drill/Curette Epiphysiodesis of the Distal Femoral Physis or the Proximal Tibial Physis

Preparation of the Physis

The level of the physis is identified both medially and laterally using fluoroscopy and a metal marker on the skin (TECH FIG 1A).

A 5-mm skin incision is made with a scalpel at the level of the physeal plate both medially and laterally (TECH FIG 1B).

 

 

 

 

TECH FIG 1 • A. A metal pointer is used to identify the level of the physis under fluoroscopy. B. A 5-mm longitudinal incision is made at the level of the physis. C. A 4.5-mm drill is used to enter the physis medially and laterally. D,E. Magnetic resonance imaging (MRI) physeal map of distal femoral and proximal tibial physis showing the intended path of the drills/curettes for percutaneous drill/curette epiphysiodesis.

 

 

A 4.5-mm drill is used to enter the medial cortex and is passed across the physis toward the lateral side (TECH FIG 1C). It is directed straight across, and then the drilling hand is raised and lowered to redirect the drill such that it passes anteriorly and posteriorly. Care is taken to avoid exiting the cortex anteriorly or posteriorly. When drilling the proximal tibial physis, care should be taken to avoid injury to the tibial tubercle apophysis (TECH FIG 1D,E).

 

We prefer making a second incision to repeat the process from the lateral side of the physis. However, it is possible to perform

 

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the femoral and/or tibial epiphysiodesis from a single incision (medial or lateral).

Physeal Plate Ablation

 

A curette is advanced through the drill holes (TECH FIG 2A-C) and is used to scrape out physeal cells

anterior, posterior, laterally, cephalad, and caudad. Care is taken to avoid breaching the cortex anteriorly, posteriorly, or proximally.

 

Fluoroscopy images are saved to confirm passage of instruments across the desired region of the physis.

 

 

 

TECH FIG 2 • Curettes are passed through the medial and lateral drill holes to the midline (A), centrally (B), anteriorly, and posteriorly (C). D,E. Following curettage, radiolucent dye can be injected into the physis to demonstrate surface area that has been mechanically disrupted. F. The proximal tibial physis preoperatively, prior to mechanical disruption of the physis. G. The proximal tibial physis post drill and curette epiphysiodesis, showing removal of the physis.

 

 

Radiopaque dye can be injected into the site of the physeal disruption to confirm ablation of the physis (TECH FIG 2D,E).

 

The goal is to ablate at least 50% of the physis medially and laterally.

 

Following epiphysiodesis, the physis is no longer easily distinguished on radiographs (TECH FIG 2F,G).

Wound Closure

 

The wound is closed in a layered fashion as per the surgeon's preferences.

• Drill/Curette Epiphysiodesis of the Proximal Fibula

   

  The anterolateral incision used for epiphysiodesis of the lateral tibia can be used for epiphysiodesis of the proximal fibula.

   

  Directing the drill in the plane of the fibular physis puts the common peroneal nerve at risk (TECH FIG 3A).

   

  To avoid injury to the common peroneal nerve, the fibular cortex is entered at the anterior superior aspect of the fibula, through the epiphysis (TECH FIG 3B).

   

  The drill and curette are passed from proximal to distal across the physis.

   

  The most proximal aspect of the fibula is usually at the level of the tibial physis.

   

  The curette is used to ablate the entire central area of the physis of the fibula to achieve epiphysiodesis (TECH FIG 3C).

   

   

   

  TECH FIG 3 • A. Dissection of the common peroneal nerve at the level of the fibular head. (continued)

   

   

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  TECH FIG 3 • (continued) B. A drill is used to enter the anterior superior aspect of the proximal fibula, followed by a curette. C. Disruption at the central portion of the proximal fibular physis results in bridging bone across the physis.

• Screw Epiphysiodesis

Femoral Screw

 

Fluoroscopy is used to mark the physis and the desired entry site of the guidewires both medially and laterally (TECH FIG 4A).

 

In the distal femur, guidewires are placed in an antegrade fashion, with an 8-mm skin incision placed approximately 5 cm proximal to the physis both medially and laterally.

 

The guidewire is placed such that the medial wire crosses the lateral half of the physis and the lateral guidewire crosses the physis at the medial half of the physis (TECH FIG 4B,C).

 

The wires extend into the epiphysis and avoid entry into the joint.

 

The guidewires are then over drilled with a 5-mm drill, and 7.3-mm fully threaded cannulated screws are placed across the growth plate (TECH FIG 4D,E).

 

Fully threaded screws are used for ease of removal.

 

 

 

TECH FIG 4 • A. Fluoroscopy is used to mark out the planned trajectory of the screws. B. On the AP view, the medial femoral screw should cross the physis at the middle of the lateral half of the physis and the lateral femoral screw should cross the physis at the middle of the medial half of the physis. C. On the lateral view, both screws should pass as close to midline as possible. Green lines indicate midline. Red dots indicate ideal crossing point for the screws. D,E. Two fully threaded 7.3-mm cannulated screws are shown directed antegrade in the distal femur and retrograde in the proximal tibia.

Tibial Screw

 

For tibial screw placement, the wires are retrograde, with 8-mm incisions made medially and laterally approximately 5 cm distal to the physis, and guidewires directed with a distal starting point, aiming proximally.

 

Care should be taken to avoid penetrating the subchondral bone with the screw tips.

 

Due to posterior tibial slope, AP x-rays with variable degrees of flexion can help to demonstrate the joint surface and true position of the screw tips.

Wound Closure

 

The incisions are irrigated and closed in the surgeon's preferred method. Sterile dressings are applied. The patient can weight bear as tolerated with crutches and is counseled to wean off crutches and gradually increase activity as tolerated.

 

 

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PEARLS AND PITFALLS

 

 

	Discrepancy ▪ Bone age is typically used for calculations of remaining growth. between bone age and chronologic age     Imaging ▪ Recently, EOS biplanar imaging systems have been shown to be equally accurate/reliable with the added benefit of imaging the patient in a standing position such that leg length and alignment can be obtained from a single low-dose image.     Prominent ▪ Patients should be advised that screws may be palpable. Using a fully hardware threaded screw and removing the screw as soon as possible following complete physeal closure will facilitate ease of screw removal.     Screw ▪ Screws placed asymmetrically, outside of the preferred location, and those placement with less than 4 threads across the physis may be at higher risk for failure of epiphysiodesis or development of an angular deformity.     Neuromuscular, ▪ Patients with hemiplegia, foot drop, or other neurologic conditions may have weak and short difficulty with toe-catch and/or tripping. Leaving the affected leg short by 1-1.5 extremity cm may be beneficial in this setting.     Follow-up to ▪ Some diseases tend to produce growth in a manner that is poorly predictable. maturity If the limb lengths correct and remaining growth causes overshortening of the long side, contralateral epiphysiodesis may be required.

 

 

POSTOPERATIVE CARE

 

Drill epiphysiodesis disrupts a large surface area of the physis. Although the cortex is intact with the exception of the medial and lateral drill holes, this procedure is considered potentially destabilizing. For this reason, patients are typically provided with a knee immobilizer, in extension. They may weight bear as tolerated.

Crutches and modified weight bearing may be used as symptoms require. Patients are typically kept out of sports and high-impact activities for 4 to 6 weeks.

 

Screw epiphysiodesis is not typically considered destabilizing. Patients can be discharged in a soft dressing. They may weight bear as tolerated. Crutches, a knee immobilizer, and modified weight bearing may be used as symptoms require. As this is not considered a destabilizing procedure, patients are not restricted from

returning to sports and may return as tolerated.7

 

 

Clinical examination should be performed at 2 weeks postoperatively and clinical and radiographic examinations every 6 months until maturity to determine closure of the physis and assess for possible complications, including angular deformity or failure of growth arrest.

 

Full-length standing plain films or EOS are the preferred radiographic modality, although CT scanogram or plain x-rays may also be used.

 

Physeal closure following mechanical ablation (drill/curette) has been reported as early as 1 month, and complete closure has been documented at 3 months by radiostereotactic analysis.11

 

Growth inhibition may be delayed by at least 6 months in screw epiphysiodesis, and one study23 has reported physeal closure to be delayed to approximately 1 year following screw epiphysiodesis.

 

OUTCOMES

 

Outcomes and complications associated with the two percutaneous techniques are summarized in Table 1.

 

Both percutaneous drill epiphysiodesis and percutaneous screw epiphysiodesis13 provide for improved cosmesis and more rapid recovery than traditional open techniques of epiphysiodesis.3

 

In a small retrospective series, drill epiphysiodesis was compared to medial and lateral 8-plates (peripheral tether). Growth inhibition was significantly less with 8-plate epiphysiodesis, and the authors

recommended against the use of medial and lateral 8 plates for equalization of leg lengths.24

Table 1 Outcomes and Complications Associated with the Two Percutaneous Techniques

Parameter

Drill

Screw

Time to distal femoral physeal closure

3 mo by RSA11

Within 6 mo19

Time to proximal tibial physeal closure

3 mo by RSA11

Within 6 mo19

Reoperation rate

0%-17%5,24

0%-18%

Peroneal nerve palsy

5% (fibular epiphysiodesis) Not assessed

 

 

Medial and lateral staples used for limb length equalization has been associated with mechanical axis deviation in over 50% of cases, and authors have advised caution in using medial and lateral staples for equalization of leg lengths.

 

Development of angular deformity	0%5,14	0%-20%
Failure of growth arrest	0%-13%	0%-20%
Infection	0%-7%	0%
Hematoma 2%-5% 0%
Knee effusion	4%-5%	Not assessed
Skin blisters	9%	Not assessed

 

	Fracture 2% 0%     Joint penetration 2% Not assessed     Hardware failure N/A 2.3% Exostosis/heterotopic bone formation 3%16 Not assessed RSA, radiostereotactic.

 

 

 

 

 

 

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COMPLICATIONS

Complication rates range from 2.9% to 33% for percutaneous mechanical ablation technique and 16% to 27% for percutaneous transphyseal screw techniques.4

Reported complications and rates summarized from multiple published series are given in Table 1.

 

 

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2. Anderson M, Messner M, Green WT. Distribution of lengths of the normal femur and tibia in children from one to eighteen years of age. J Bone Joint Surg Am 1964;46:1197-1202.

    

    

3. Babu LV, Evans O, Sankar A, et al. Epiphysiodesis for limb length discrepancy: a comparison of two methods. Strategies Trauma Limb Reconstr 2014;9(1):1-3. doi:10.1007/s11751-013-0180-9.

    

    

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11. Gunderson RB, Horn J, Kibsgard T, et al. Negative correlation between extent of physeal ablation after percutaneous permanent physiodesis and postoperative growth: volume computer tomography and radiostereometric analysis of 37 physes in 27 patients. Acta Orthop 2013;84(4):426-430.

     

     

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23. Song MH, Choi ES, Park MS, et al. Effects and complications of percutaneous epiphysiodesis using transphyseal screws in the management of leg length discrepancy: optimal operation timing and techniques to avoid complications [published online ahead of print June 26, 2014]. J Pediatr Orthop.

     

     

24. Stewart D, Cheema A, Szalay EA. Dual 8-plate technique is not as effective as ablation for epiphysiodesis about the knee. J Pediatr Orthop 2013;33(8):843-846.