Evaluation of Leg Length Discrepancy in Children

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Leg Length Discrepancy in Children CME Review Article

Editor’s Note: This is the third of four articles to be published in 2004 for which a total of up to 4 Category 1 CME credit hours can be earned. Instructions for how credit hours can be earned appear after the Table of Contents. Exam questions will appear after the article.

Stephen J. Stricker, MD, Terrance Hunt, BS

Target Audience referral is recommended for LLD predicted to exceed 2 cm. The most reliable methods for measuring LLD clinically and radiographi- This CME activity is intended for physicians, medical students cally are presented. Options for orthopaedic management and prediction of LLD are briefly outlined. Int Pediatr. 2004;19(3):134-142. and nurse practitioners. Pediatric emergency department physicians, emergency physicians, pediatricians, and family Key words: Leg length discrepancy (LLD), lower-limb length in- practitioners will find this information especially useful. equality, hemihypertrophy, growth prediction, epiphysiodesis

Learning Objectives Introduction After completion of this article, the reader will be able to: Approximately 15% of the adult population has a 1. Describe what leg length discrepancies are. leg length discrepancy (LLD) measuring greater than 2. Summarize common congenital and acquired causes of leg 1 cm.1 Most LLDs < 2 cm are idiopathic, due to length discrepancy. normal anatomic variation (asymmetry) of the human 3. Discuss important medical and functional problems body. Such minor discrepancies are generally believed associated with leg length discrepancies. to cause few functional problems and often go 4. State the most reliable methods for measuring leg length unnoticed by patients. Larger discrepancies typically discrepancy both clinically and radiographically. have demonstrable underlying causes and often require 5. Discuss treatment options once the leg length discrepancy has treatment. The authors discuss a systematic approach been estimated. to the assessment of LLD, with emphasis on optimal measurement techniques and on avoidance of measurement error. Abstract Presentation of LLD The authors list common congenital and acquired causes of leg length discrepancy (LLD) to assist the primary care physician with LLDs exceeding 2 cm may alter normal gait differential diagnosis. Important medical problems associated with patterns, resulting in a painless limp.2-5 Most young LLD are discussed, emphasizing the risk of malignant neoplasm children compensate by tiptoe gait on the short limb. with Beckwith-Wiedemann hemihypertrophy. Potential functional Older children may “vault” over the longer extremity, problems caused by LLD in children are discussed. Orthopaedic causing an excessive rise in the pelvis with each step. These compensatory mechanisms may result in slight 5 From University of Miami School of Medicine, Department of increased energy expenditure, but healthy children with Orthopaedic Surgery (Dr Stricker and Hunt). LLD rarely complain of easy fatigability. Some studies regarding adults suggest that LLDs Address reprint requests to Stephen J. Stricker, MD, Professor 6 7 and Chief, Pediatric Orthopaedics, University of Miami School > 2 cm can result in low back pain, structural scoliosis, of Medicine, Department of Orthopaedic Surgery (D-27), P.O. and hip degeneration,8 but another body of literature Box 016960, Miami, FL 33101.

134 International Pediatrics/Vol. 19/No. 3/2004 Leg Length Discrepancy in Children refutes these findings.9-11 Certainly, children rarely Causes of LLD complain of back or hip pain as a result of LLD. Most often children are evaluated for LLD because While it is not feasible to list all potential causes of the parents suspect a limp or because pelvic tilt is noted LLD, some of the more common etiologies of during the Adam’s screening test for scoliosis. congenital and acquired LLD are listed in Table 1.

Table 1 - Common Etiologies of Leg Length Discrepancy

Congenital Clinical findings:

Proximal focal femoral deficiency + Allis, thigh skin dimple Developmental coxa vara + Allis, limited abduction Developmental hip dysplasia + Allis, limited abduction Fibular hemimelia Absent lateral toes, valgus ankle Tibial hemimelia Severe varus ankle, leg skin dimple Congenital posteromedial bowing tibia Apparent ankle dorsiflexion Congenital tibial pseudarthrosis Neurofibromatosis, anterolateral bowing Nonsyndromic hemihypertrophy

Physeal growth disturbance Ischemic physeal arrest (Perthes, post-infectious, limb ischemia, septic shock) Blount’s disease (tibia vara) Radiation therapy Juxta-physeal tumor or bone cyst Multiple exostosis / osteochondromatosis

Trauma Traumatic physeal growth arrest Fracture malunion (overriding) Slipped capital femoral epiphysis (SCFE)

Hyperemia Posttraumatic overgrowth (common after femur shaft fracture) Chronic knee synovitis with overgrowth Chronic osteomyelitis Hemophilia Rheumatoid arthritis Osteoid osteoma Arterio-venous malformation (AVM) or hemangiomatosis Post-surgical hyperemia

Neuromuscular Poliomyelitis Spastic hemiplegia (cerebral palsy, stroke) Spinal cord anomaly (tethered cord, syrinx)

Syndromes Clinical findings: Ollier’s Multiple enchondromatosis Russell-Silver Limb asymmetry, growth retardation, clinodactyly Beckwith-Wiedemann Neonatal hypoglycemia, hemihypertrophy Proteus Nevi, hemihypertrophy, macrodactyly, hamartomata Klippel-Trenaunay Hemangiomata, venous insufficiency Neurofibromatosis Local gigantism, macrodactyly, cafe-au-lait nevi Conradi-Hunerman Stippled epiphyses, short stature Vivid cutis marmorata Marbled skin markings, hemiatrophy Hemiatrophy Facial and corporal hemiatrophy

International Pediatrics/Vol. 19/No. 3/2004 135 Leg Length Discrepancy in Children

Many of the congenital anomalies involve hypoplasia or hemihypertrophy of a limb and have telltale skin markings.12-15 An anterior skin dimple portends an underlying congenital hypoplasia or hemimelia within the limb segment (Fig. 1). Lower extremity hemihypertrophies and hemiatrophies may also result in unequal limb circumference and foot sizes.16-18 All congenital bowing deformities of the tibia result in growth retardation. Infrequently, LLD results from hereditary conditions such as familial exostosis or skeletal dysplasia, so family history is important. The physician should search for history of infection, trauma, or birth complications which may explain LLD. Medications, intraosseous infusions,19 and growth hormone20 are not known to cause or aggravate LLD. Chronic hyperemia may result in limb overgrowth, especially if the hyperemia is near major knee growth plates,21 so evaluation for asymmetrical pulses, vascular markings, and bruits is prudent. Juxta-physeal osteonecrosis, as in Perthes disease, radiation therapy,22,23 or limb ischemia24 may cause premature physeal closure. Hemiatrophy usually results from neurological causes, such as spastic hemiparesis or tethered cord, so examination of the back, feet, and reflexes is important. In summary, the list of possible causes of LLD is extensive, but the differential diagnosis can quickly be narrowed with a thorough 25,26 history and physical examination. Fig 1- A skin dimple portends osseous hypoplasia within the limb segment. This infant has right congenital fibular hemimelia. Hemihypertrophy

The term hemihypertrophy is defined as enlargement promptly, and BWS has a 7–10% risk of associated of one side of the body to a greater degree than can malignant tumors, usually prior to age 5. be attributed to normal variation.16 Classic total hemi- Hemihypertrophy occurs in only 13% of BWS hypertrophy implies enlargement of the face, cases; however, infants with BWS and hemihypertrophy extremities, trunk, and internal organs on one side. have a 40% chance of developing malignant tumors, Limited hemihypertrophy may involve a portion of the most common being Wilms’ tumor, adrenal cortical the body on one side. Hemihypertrophy may also be carcinoma, or hepatoblastoma.27 For this reason, tumor classified as syndromic or non-syndromic. screening with thorough clinical examination plus The primary care physician must carefully assess abdominal ultrasound is recommended every 3–4 neonates for hemihypertrophy since it can be associated months until age 7, then every six months until with severe neonatal hypoglycemia or with malignant maturity.27,28 Annual urinalysis and serum alpha- tumors, as seen in Beckwith-Wiedemann syndrome fetoprotein are also recommended. Genetic evaluation (BWS).27,28 This syndrome should be considered in is reasonable to verify the diagnosis and to provide infants with hemihypertrophy who are large for genetic counseling. gestational age. BWS consists of exophthalmos, Various benign and malignant tumors may occur macroglossia, gigantism, visceromegaly, abdominal wall in other types of syndromic hemihypertrophy, such as defects, and neonatal hypoglycemia. Developmental neurofibromatosis,12 Klippel-Trenaunay syndrome,14 delay may occur if hypoglycemia is not treated and Proteus syndrome.15 Non-syndromic

136 International Pediatrics/Vol. 19/No. 3/2004 Leg Length Discrepancy in Children hemihypertrophy lacks vascular or cutaneous lesions, bending test. Palpation of the iliac wings may be less is typically not familial, and has no increased risk of reliable in obese patients or in children with significant neoplasia.16 trunk asymmetry caused by lumbar scoliosis. If a LLD is suspected by pelvic tilt during standing, Clinical Assessment LLD the location of discrepancy may be verified by performing the Allis test and the reverse Allis test. The While medical students are frequently taught to use Allis test (also called Galeazzi test) is performed in the a tape measure from the malleoli to the umbilicus (or supine patient by noting relative knee heights when to the anterior superior iliac spines), such landmarks both hips and knees are flexed 90°.30 This will will often result in imprecise estimates of LLD.10,29 determine how much discrepancy is located in the thigh For patients who can stand in anatomic position, a segment. The patient is then turned prone with the more reliable clinical measurement consists of knees and ankles at 90° (and both hips in neutral simultaneous palpation of both iliac crests.29 Wood rotation) to determine how much LLD is present blocks (or a portion of a phone book) can be placed below the knees. These clinical tests cannot be beneath the foot of the shorter limb until the pelvis is performed if there exist significant contractures, which leveled by palpation (Fig. 2). A leveled pelvis may be limit hip, knee, or ankle motion. When properly used verified by scoliometer using the Adam’s forward in combination, the standing palpation method and Allis tests can provide a reasonable clinical estimate of LLD. The clinician can sometimes erroneously diagnose a true LLD when the patient in fact has a functional discrepancy resulting from an angular deformity of one limb or a joint contracture in the lower extremity (LE). For instance, a lower extremity may have symmetrical bone lengths, but will seem too short if there exists a unilateral knee flexion contracture, bowleg, or hip adduction contracture. A lower limb may seem too long if there is an Achilles contracture elevating the heel. Therefore, clinical exam for LLD must include assessment of LE joint motion, angulation, and motor function.

Radiographic Measurement of LLD

There are several methods for radiographic measurement of LLD, and each may be optimal in certain circumstances. One of the simplest techniques is to obtain a standing (or supine) AP radiograph of both LEs on a long x-ray cassette. Magnification error is minimal for small children, but the technician must be certain that both knees are extended during the exposure. A standing x-ray will show all sources of discrepancy from the pelvis to the heel, and can show frontal-plane angular deformities such a genu varum. The scanogram (orthoroentgenogram) is taken with Fig 2- Clinical estimate of LLD in the standing patient. Blocks of the supine patient lying with a ruler between the lower known thickness are placed under the short limb until the pelvis extremities. Three separate exposures are taken, each is level by palpation. perpendicular to the hips, knees, and ankles, thereby avoiding magnification error (Fig. 3). This method is

International Pediatrics/Vol. 19/No. 3/2004 137 Leg Length Discrepancy in Children

measurement from the top of the femoral head to the ankle joint.

Prediction of LLD

Prediction of LLD can be difficult because discrepancies may be static, regressive, or progressive.33 In order to plan treatment, the orthopaedic surgeon must try to predict how much LLD an untreated patient will likely develop by skeletal maturity. Such predictions facilitate timing of growth-retarding procedures such as epiphysiodesis, and help to determine if limb length equalization is even feasible, given surgical limitations. Because children mature at different ages, most of the techniques for prediction of LLD are based upon skeletal age rather than chronologic age. Skeletal age is typically determined by comparing an AP radiograph of the child’s left hand and wrist with radiographs in the Greulich-Pyle atlas.34 Skeletal ages are less accurate prior to age 6, but accuracy is improved by placing more emphasis on the hand bones rather than on the carpal bones.35 Skeletal age should be interpreted with caution if there is hemihypertrophy or hemiatrophy involving the left hand. Use of a normal right-hand radiograph is reasonable if anomalies preclude use of the left hand. While other methods have been described, the Fig 3- Measurement of LLD with a standard scanogram. This child has congenital left tibial pseudarthrosis. authors will briefly summarize four of the LLD prediction methods in common usage. The arithmetic method36 provides a rough estimate of growth readily available and is accurate for older children, but potential for children older than 10 years. This method may be less reliable for young children who are likely assumes that the distal femoral physis grows 10 mm to move between exposures. Scanograms are per year and the proximal tibial physis grows 6 mm inappropriate for angular deformities such as knee per year. The method also assumes that boys reach flexion contracture or severe genu valgum/varum. In maturity at chronologic age 16, and girls at age 14. addition, the scanogram does not allow measurement The Green-Anderson growth-remaining charts37 of hindfoot discrepancies as may occur with subtalar may be used to estimate growth potential in the distal coalition or some congenital foot deformities. The femoral and proximal tibial physes at various skeletal scanogram is the most frequently used technique for ages. There are separate charts for boys and for girls. routine measurement of LLD. This method has withstood the test of time, and is For patients who have significant angular deformities especially useful if a treatment decision needs to be or flexion contractures of the lower extremities, a made without the benefit of serial measurements. biplanar CT scanogram is the preferred method for The Moseley graph38 is a logarithmic radiographic measurement of LLD.31,32 The CT representation of the Green-Anderson chart, which scanogram (scout view) has less radiation exposure allows the growth of both lower limbs to be plotted than a standard scanogram, but is more expensive and as straight lines. This method requires at least 2 often requires another appointment. Unless inclusion scanogram measurements, but becomes more accurate of hindfoot length is specifically requested during a if one has the luxury of multiple measurements over CT scanogram, the radiologist will typically provide a many years.

138 International Pediatrics/Vol. 19/No. 3/2004 Leg Length Discrepancy in Children

Finally, the multiplier method of Paley et al39 allows one to estimate future LLD for many congenital anomalies at an early age by assuming that lower extremity proportions will remain constant throughout growth. Each prediction method described above may be appropriate for certain circumstances, and recent studies have shown little difference in accuracy among the various methods.40,41 Skeletal ages are generally considered accurate to ± 1 year, which is sufficient to allow equalization of the lower limbs to within 1.5 cm.40,42

Treatment Options for LLD

Once the predicted LLD has been estimated, treatment options may be formulated. Localization of the discrepancy within the femur and/or tibia will help determine where treatment should be rendered, since one goal is to maintain symmetry of limb segments. Treatment may also depend on the predicted height of the patient, with shortening procedures less desirable in patients with shorter stature. Mature height may be predicted by using the patient’s skeletal age to extrapolate his growth curve, which is available on the pediatrician’s height-weight chart. The goal of treatment is to obtain nearly equal limb lengths, preserve patient height, maintain body proportions, and minimize surgical risk to the patient. If a patient Fig 4- Epiphysiodesis (growth arrest) procedures are often has a stiff knee or foot drop, it may be desirable to performed percutaneously to minimize scarring. A drill bit is leave the affected limb 1–2 cm short to allow the foot used to make multiple passes through the growth cartilage. to clear the floor during ambulation. Virtually all orthopaedic surgeons agree that LLD surgical arrest (epiphysiodesis) of the distal femoral < 2 cm should be treated non-surgically, with and/or proximal tibial growth plates. In recent years, observation, or with an internal (hidden) heel-lift if percutaneous epiphysiodesis techniques (Fig. 4) have the patient has a visible limp. Internal heel-lifts are been developed to minimize scarring.44,47 If growth generally limited to 1 cm thickness. Larger lifts will plates are closed, acute femoral shortening of up to 5 elevate the heel out of the shoe, make the shoe feel cm, may be performed utilizing intramedullary rod tight, or aggravate contracture of the Achilles tendon.43 stabilization to allow early rehabilitation.48 Tibial Therefore, shoe-lifts > 1 cm must generally be added shortening is rarely performed due to higher risk of externally on the shoe sole where they are visible. persistent muscle weakness, nonunion, and External lifts greater than 5 cm may become quite heavy compartment syndrome.49 and unstable, and are poorly tolerated as permanent Predicted LLDs of 5–20 cm usually require one treatment of LLD. The orthopaedic surgeon will or more limb lengthenings, adding contralateral limb usually prescribe a lift 1–1.5 cm smaller than the actual shortening for more severe LLD.50 Limb-lengthening discrepancy. techniques involve osteotomy followed by gradual (1 Unless a patient has very short stature, a LLD of mm per day) distraction with an external fixator. Bone 2–5 cm is usually treated with shortening of the longer tissue spontaneously regenerates within the gap limb. If there is sufficient growth remaining, the longer produced (Fig. 5). The time required for lengthening limb may be safely and gradually shortened with by “distraction histogenesis” averages 1-2 months per

International Pediatrics/Vol. 19/No. 3/2004 139 Leg Length Discrepancy in Children

Fig 5- Femoral lengthening with the Ilizarov technique involves osteotomy followed by gradual distraction with an external fixator. Finally, regenerate bone forms and solidifies within the gap. centimeter of distraction.51 Lengthenings greater than which can be associated with neoplasia. Thorough 20% of the original bone length are considered very history, physical exam, and plain radiographic imaging high risk, but lengthenings of 4–5 cm are usually will usually reveal the etiology of LLD. Orthopaedic manageable with relatively lower risk of joint referral is appropriate for management of LLD subluxation, neurovascular injury, or permanent muscle predicted to exceed 2 cm, but smaller discrepancies contracture.51,52 rarely require treatment or cause functional problems. Limb lengthening is a prolonged and somewhat The primary care physician and orthopaedic surgeon painful undertaking, and may place a psychological must work together to assess the patient’s needs and burden on the patient and family.53 The safety and to formulate a treatment strategy which takes into efficacy of limb lengthening has improved significantly account the medical risks, family support, and access since the Ilizarov technique was introduced to North to specialized pediatric orthopaedic care. America in the late 1980’s.54 Even so, with few exceptions, patients with predicted LLD of > 20 cm References are typically better candidates for amputation and prosthetic fitting, especially if severe foot deformity is 1. Rush WA, Steiner HA. A study of lower extremity length present. inequality. Am J Roentgenol. 1946;56:616-23. 2. Gross RH. Leg length discrepancy: How much is too In summary, the primary care physician often has much? Orthopedics 1978;1:307-10. the first opportunity to diagnose LLD and to look 3. Kaufman KR, Miller LS, Sutherland DH. Gait asymmetry for possible congenital, developmental, or genetic in patients with limb-length inequality. J Pediatr Orthop. 1996;16:144-50. causes. The pediatrician must be aware of relatively 4. Liu X-C, Fabry G, Molenaers G, Lammens J, Moens P. rare syndromes associated with LLD, especially BWS, Kinematic and kinetic asymmetry in patients with leg- length discrepancy. J Pediatr Orthop. 1998;18:187-9.

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5. Song KM, Halliday SE, Little DG. The effect of limb- 26. Stanitski DF. Limb-length inequality: assessment and length discrepancy on gait. J Bone Joint Surg Am. treatment options. J Am Acad Orthop Surg 1999;7:143-53. 1997;79:1690-8. 27. DeBaun MR, Tucker MA. Risk of cancer during the first 6. Giles LG, Taylor JR. Low-back pain associated with leg four years of life in children from The Beckwith- length inequality. Spine 1981;6:510-21. Wiedemann Syndrome Registry. J Pediatr 1998;132:398- 7. Papaioannou T, Stokes I, Kenwright J. Scoliosis associated 400. with limb-length inequality. J Bone Joint Surg Am 28. Weng EY, Mortier GR, Graham JM Jr. Beckwith- 1982;64:59-62. Wiedemann syndrome. An update and review for the 8. Gofton JP, Trueman GE. Studies in osteoarthritis of hip: primary pediatrician. Clin Pediatr 1995;34:317-26. part II, osteoarthritis of hip and leg length disparity. Can 29. Woerman AL, Binder-Macleod SA. Leg length discrepancy Med Assoc J 1971;104:791-9. assessment: accuracy and precision in five clinical methods 9. Brand RA, Yack HJ. Effects of leg length discrepancies of evaluation. J Orthop Sports Phys Ther 1984;5:230-9. on the forces at the hip joint. Clin Orthop 1996;333:172- 30. Stricker SJ, Barone SR. Tips about hips in children: review 80. article. Int Pediatr 2001;16:196-205. 10. Grundy PF, Roberts CJ. Does unequal leg length cause 31. Aaron A, Weinstein D, Thickman D, Eilert R. Comparison back pain? A case-control study. Lancet 1984;2:256-8. of orthoroentgenography and computed tomography in 11. Soukka A, Alaranta H, Tallroth K, Heliövaara M. Leg- the measurement of limb-length discrepancy. J Bone Joint length inequality in people of working age. The Surg Am 1992;74:897-902. association between mild inequality and low-back pain is 32. Helms CA, McCarthy S. CT scanograms for measuring questionable. Spine 1991;16:429-31. leg length discrepancy. Radiology 1984;151:802. 12. Crawford AH, Schorry EK. Neurofibromatosis in 33. Shapiro F. Developmental patterns in lower-extremity children: the role of the orthopaedist. J Am Acad Orthop length discrepancies. J Bone Joint Surg Am 1982;64-A:639- Surg 1999;7:217-30. 51. 13. Dutkowsky JP, Kasser JR, Kaplan LC. Leg length 34. Greulich WW, Pyle SI. Radiographic atlas of skeletal development discrepancy associated wtih vivid cutis marmorata. J of the hand and wrist. 2nd ed. Stanford, California: Stanford Pediatr Orthop 1993;13:456-8. University Press, 1959. 14. Rogalski R, Hensinger R, Loder R. Vascular abnormalities 35. Carpenter CT, Lester EL. Skeletal age determination in of the extremities: clinical findings and management. J young children: analysis of three regions of the hand / Pediatr Orthop 1993;13:9-14. wrist film. J Pediatr Orthop 1993;13:76-9. 15. Stricker S. Musculoskeletal manifestations of Proteus 36. Westh RN, Menelaus MB. A simple calculation for the syndrome: report of two cases with literature review. J timing of epiphyseal arrest: a further report. J Bone Joint Pediatr Orthop 1992;12:667-74. Surg Br 1981;63:117-9. 16. Ballock RT, Wiesner GL, Myers MT, Thompson GH. 37. Green WT, Anderson M. Experiences with epiphyseal Current concepts review. Hemihypertrophy. Concepts arrest in correcting discrepancies in length of the lower and controversies. J Bone Joint Surg Am 1997;79-A:1731-8. extremities in infantile paralysis: a method of predicting 17. Bettin D, Karbowski A, Schwering L. Congenital ball- the effect. J Bone Joint Surg Am 1947;29:659-75. and-socket anomaly of the ankle. J Pediatr Orthop 38. Moseley CF: A straight-line graph for leg-length 1996;16:492-6. discrepancies. Clin Orthop 1978;136:33-40. 18. Finch GD, Dawe CJ. Hemiatrophy. J Pediatr Orthop 39. Paley D, Bhave A, Herzenberg JE, Bowen JR: Multiplier 2003;23:99-101. method for predicting limb-length discrepancy. J Bone 19. Fiser RT, Walker WM, Seibert JJ, McCarthy R, Fiser DH. Joint Surg Am 2000;82:1432-46. Tibial length following intraosseous infusion: a 40. Little DG, Nigo L, Aiona MD. Deficiencies of current prospective, radiographic analysis. Pediatr Emer Care methods for the timing of epiphysiodesis. J Pediatr Orthop 1997;13:186-8. 1996;16:173-9. 20. Rizzo V, Traggiai C, Stanhope R. Growth hormone 41. Dewaele J, Fabry G. The timing of epiphysiodesis: a treatment does not alter lower limb asymmetry in children comparative study between the use of the method of with Russell-Silver syndrome. Horm Res 2001;56:114-6. Anderson and Green and the Moseley chart. Acta Orthop 21. Rodriguez-Merchan EC. Effects of hemophilia on articulations Belg 1992;58:43-7. of children and adults. Clin Orthop 1996;328:7-13. 42. Cundy P, Paterson D, Morris L, Foster B. Skeletal age 22. Butler MS, Robertson WW, Rate W, D’Angio GJ, Drummond estimation in leg length discrepancy. J Pediatr Orthop DS. Skeletal sequelae of radiation therapy for malignant 1988;8:513-5. childhood tumors. Clin Orthop 1990;251:235-40. 43. Dahl MT. Limb length discrepancy. Pediatr Clin North Am 23. Robertson WW Jr, Butler MS, D’Angio GJ, Rate WR. Leg 1996;43:849-65. length discrepancy following irradiation for childhood 44. Canale ST, Christian CA. Techniques for epiphysiodesis tumors. J Pediatr Orthop 1991;11:284-7. about the knee. Clin Orthop 1990;255:81-85. 24. Farrar MJ, Bennet GC, Wilson NIL, Azmy A. The orthopaedic 45. Horton GA, Olney BW. Epiphysiodesis of the lower implications of peripheral limb ischaemia in infants and extremity: results of the percutaneous technique. J Pediatr children. J Bone Joint Surg Br 1996;78:930-3. Orthop 1996;16:180-182. 25. Grayhack JJ, Carroll NC. Projected limb length inequality: 46. Porat S, Peyser A, Robin GC. Equalization of lower limbs by selecting patients for surgery. Orthop Clin North Am epiphysiodesis: results of treatment. J Pediatr Orthop 1991;22:581-7. 1991;11:442-8.

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47. Surdam JW, Morris CD, DeWeese JD, Drvaric DM. Leg 52. Velazquez RJ, Bell DF, Armstrong PF, Babyn P, Tibshirani length inequality and epiphysiodesis: review of 96 cases. R. Complications of use of the Ilizarov technique in the J Pediatr Orthop 2003;23:381-4. correction of limb deformities in children. J Bone Joint 48. Chapman ME, Duwelius PJ, Bray TJ, Gordon JE. Closed Surg Am 1993;75:1148-56. intramedullary femoral osteotomy. Shortening and 53. Hrutkay JM, Eilert RE. Operative lengthening of the derotation procedures. Clin Orthop 1993;287:245-51. lower extremity and associated psychological aspects: the 49. Kenwright J, Albinana J. Problems encountered in leg Children’s Hospital Experience. J Pediatr Orthop shortening. J Bone Joint Surg Br 1991;73:671-5. 1990;10:373-7. 50. Naudie D, Hamdy RC, Fassier F, Duhaime M. 54. Ilizarov GA. The tension-stress effect of the genesis and Complications of limb-lengthening in children who have growth of tissues: Part II. The influence of the rate and an underlying bone disorder. J Bone Joint Surg Am frequency of distraction. Clin Orthop 1989;239:263-85. 1998;80:18-24. 51. Paley D. Current techniques of limb lengthening. J Pediatr Orthop 1988;8:73-92. © Miami Children’s Hospital 2004

142 International Pediatrics/Vol. 19/No. 3/2004 Leg Length Discrepancy in Children

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International Pediatrics/Vol. 19/No. 3/2004 143 Leg Length Discrepancy in Children

CONTINUING MEDICAL EDUCATION

September 2004

EXAM POSTMARKED DEADLINE: SEPTEMBER 30, 2005

Evaluation of Leg Length Discrepancy in Children Stephen J. Stricker, MD, Terrance Hunt, BS. Int Pediatr 2004;19(3)134-142.

QUESTIONS

1. Leg length discrepancies measuring less than 2 centimeters at skeletal maturity are usually: A. symptomatic B. idiopathic C. syndromic D. congenital E. progressive

2. Which of the following correctly describes Beckwith-Wiedemann syndrome? A. associated with macroglossia, visceromegaly, and neonatal hyperglycemia B. always associated with hemihypertrophy and leg length discrepancy C. childhood screening for malignant neoplasia is advisable D. associated with intrauterine growth retardation E. all of the above

3. Which of the following represents entirely a functional leg length discrepancy? A. congenital femoral hypoplasia B. congenital fibular hemimelia C. congenital posteromedial tibial bowing D. unilateral fixed knee flexion contracture E. non-syndromic total hemihypertrophy

4. Which of the following radiographic techniques is preferred for measurements of leg length discrepancy in a child with a 40° unilateral knee flexion contracture? A. supine AP radiograph of both lower extremities B. standing AP radiograph of both lower extremities C. scanogram of both lower extremities D. standing AP pelvis radiograph E. biplanar CT scanogram of both lower extremities

5. A 12-year-old boy with a leg length discrepancy predicted to be 3 centimeters at maturity would typically be managed with: A. observation B. permanent shoe lift C. epiphysiodesis (growth plate arrest) D. acute femoral shortening with intramedullary rod fixation E. tibial lengthening with distraction histiogenesis and external fixation

144 International Pediatrics/Vol. 19/No. 3/2004 Leg Length Discrepancy in Children

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