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Pediatric Genu Valgum

  • Author: Peter M Stevens, MD; Chief Editor: Dennis P Grogan, MD  more...
 
Updated: Apr 24, 2014
 

Background

Genu valgum is the Latin-derived term used to describe knock-knee deformity. While many otherwise healthy children have knock-knee deformity as a passing trait, some individuals retain or develop this deformity as a result of hereditary or genetic disorders or metabolic bone disease. The typical gait pattern is circumduction, requiring that the individual swing each leg outward while walking in order to take a step without striking the planted limb with the moving limb. Not only are the mechanics of gait compromised but also, with significant angular deformity, anterior and medial knee pain are common. These symptoms reflect the pathologic strain on the knee and its patellofemoral extensor mechanism.

For persistent genu valgum, treatment recommendations have included a wide array of options, ranging from lifestyle restriction and nonsteroidal anti-inflammatory drugs to bracing, exercise programs, and physical therapy. In recalcitrant cases, surgery may be advised. No consensus exists regarding the optimal treatment. Some surgeons focus (perhaps inappropriately) on the patella itself, favoring arthroscopic or open realignment techniques. However, if valgus malalignment of the extremity is significant, corrective osteotomy or, in the skeletally immature patient, hemiepiphysiodesis may be indicated.

Osteotomy indications and techniques have been well described in standard textbooks and orthopedic journals and are not the focus of this article. Hemiepiphysiodesis can be accomplished using the classic Phemister bone block technique, the percutaneous method, hemiphyseal stapling, or, more recently, application of a single 2-hole plate and screws around the physis. The senior author, having experience in each of these techniques, has developed the later technique in order to solve 2 of the problems sometimes encountered with staples, namely hardware fatigue and migration. The rationale and versatility of this technique for managing genu valgum are the emphasis of this article.

Images of genu valgum and its treatment are provided below:

This diagram depicts genu valgum involving the rig This diagram depicts genu valgum involving the right leg (lighter shade), where the mechanical axis falls outside the knee. The goal of treatment is to realign the limb and neutralize the mechanical axis (dotted red line), thereby mitigating the effects of gravity through guided growth of the femur and/or tibia (whatever is required to maintain a horizontal knee joint axis). The darker shade depicts normal alignment with the mechanical axis now bisecting the knee.
This 9-year-old patient has symmetrical and progre This 9-year-old patient has symmetrical and progressive genu valgum caused by a hereditary form of metaphyseal dysplasia. One method of treatment is to undertake bilateral femoral and tibial/fibular osteotomies, securing these with internal plates or external frames. However, the hospitalization and the attendant cost and risks, including peroneal nerve palsy and compartment syndrome, make this a daunting task for the surgeon and family alike. Furthermore, mobilization and weightbearing may require physical therapy but must be delayed pending initial healing of the bones.
Heretofore, stapling was a viable option. This out Heretofore, stapling was a viable option. This outpatient procedure permitted simultaneous and multiple deformity correction, without casts or delayed weightbearing. However, the concept of compressing and overpowering the physes has the drawbacks of slower correction because the fulcrum is within the physis. Provided the rigid staples did not dislodge or fatigue, satisfactory correction could be realized. If the hardware failed prematurely, the correction was either abandoned or the hardware exchanged. Compared with osteotomies, it was a risk worth taking, that is, until the advent of a better option.
The application of a single 8-plate per physis per The application of a single 8-plate per physis permits the same correction as stapling, without the potential drawbacks of implant migration or fatigue failure. Based on the principle of facilitating rather than compressing the physes, the correction occurs more rapidly and rebound growth, though possible, may be less frequent. When the mechanical axis has been restored to neutral, the plates (or metaphyseal screws) are removed (and replaced as necessary if recurrent deformity ensues).

Recent studies

Wiemann et al compared the use of the 8-plate for hemiepiphysiodesis with that of physeal stapling in 63 cases of angular deformity in lower extremities between 2000 and 2007, with 39 limbs undergoing staple hemiepiphysiodesis and 24 undergoing 8-plate hemiepiphysiodesis. The authors found the 8-plate to be as effective as staple hemiepiphysiodesis in terms of the rate of correction (approximately 10º/y, P=0.48) and complications (12.8% vs. 12.5%, P=1.0). However, patients with abnormal physes (eg, Blount disease, skeletal dysplasias) did have a higher rate of complications (27.8% vs. 6.7% for patients with normal physes, P=0.04), but there was no difference between the 8-plate group and the staple group.[1] We have not shared this experience; the complication rate is exceedingly low in both groups.[2]

After analyzing 35 patients, Jelinek et al reported a shorter operating time for implantation and explantation was noted for the 8-plate technique than for Blount stapling.[3]

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History of the Procedure

The focus of this article is the indications, techniques, complications, and outcome of guided growth using the reversible plate technique for the correction of pathologic genu valgum. Since the introduction of staples by Walter Blount in 1949, this procedure has waned in popularity, having been supplanted by the tension band plate concept. Book chapters dismiss stapling as a historical procedure, citing unpredictability and the fear of permanent physeal arrest as results of stapling. While stapling can work well, occasional breakage or migration of staples can necessitate revision of hardware or premature abandonment of this method of treatment.

Some surgeons have reverted to osteotomy of the femur and/or tibia-fibula as the definitive means of addressing genu valgum. However, this is a very invasive method fraught with potential complications, including malunion, delayed healing, infection, neurovascular compromise, and compartment syndrome. Further complicating the picture, these deformities are often bilateral, requiring a staged correction. The aggregate hospitalization, recovery time, costs, and risks make osteotomy a last resort for angular corrections (unless the physis has already closed).

Percutaneous drilling or curettage of a portion of the physis yields only a small scar and no implant is required. However, this is a permanent, irreversible technique. Therefore, its use is necessarily restricted to adolescent patients and is predicated upon precise timing of intervention, requiring close follow-up to avoid undercorrection or (worse yet) overcorrection.

Some authorities advocate using percutaneous epiphyseal transcutaneous screws as a means of achieving angular correction.[4, 5] While this is performed through a small incision, the physis is violated and the potential exists for the formation of an unwanted physeal bar, with its sequelae. To date, the potential for reversing the procedure has not been documented in younger children; therefore, the only reported cases have been in adolescents.

By comparison, guided growth, using a nonlocking 2-hole plate and screws, is a reversible and minimally invasive outpatient procedure, allowing multiple and bilateral simultaneous deformity correction. A single implant is used per physis, as shown in the images below; this serves as a tension band, allowing gradual correction with growth. Because the focal hinge of correction (CORA) is at or near the level of deformity, compensatory and unnecessary translational deformities are avoided.[6, 7]

The application of a single 8-plate per physis per The application of a single 8-plate per physis permits the same correction as stapling, without the potential drawbacks of implant migration or fatigue failure. Based on the principle of facilitating rather than compressing the physes, the correction occurs more rapidly and rebound growth, though possible, may be less frequent. When the mechanical axis has been restored to neutral, the plates (or metaphyseal screws) are removed (and replaced as necessary if recurrent deformity ensues).
This 14-year-old boy, weighing 132 kg, presented w This 14-year-old boy, weighing 132 kg, presented with activity-related anterior knee pain, circumduction gait, and difficulty with running and sports. His symptoms had been progressive over a period of 18 months despite nonoperative measures including physical therapy, activity restrictions, and nonsteroidal anti-inflammatory drug therapy.
Nine months following the insertion of 8-plates in Nine months following the insertion of 8-plates in the distal femora (1 per knee), the mechanical axis is approaching neutral and his symptoms abated. The plates were removed 2 months later, allowing for full correction of his valgus deformities. He has not had recurrence.

The previous empirical constraints related to the indications for instrumented hemi-epiphysiodesis, including appropriate age group and the etiology of deformity, have been challenged successfully using this technique, with consistently good results. During the past decade, in a personal series of more than 1000 patients, ranging in age from 19 months to 18 years, and some with pan-genu deformities, the senior author has not had a permanent physeal closure, nor have any been reported in the literature.

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Problem

Normal alignment means that the lower extremity lengths are equal and the mechanical axis (center of gravity) bisects the knee when the patient is standing erect with the patellae facing forward. This position places relatively balanced forces on the medial and lateral compartments of the knee and on the collateral ligaments, while the patella remains stable and centered in the femoral sulcus.

In children younger than 6 years, physiologic genu valgum is common but is self-limiting and innocuous. In children (of any age) with pathologic valgus, when the mechanical axis deviates into or beyond the lateral compartment of the knee whereupon, regardless of the etiology, a number of clinical problems may ensue. Medial ligamentous strain may be associated with recurrent knee pain. The patellofemoral joint may become shallow, incongruous, or unstable, causing activity-related anterior knee pain. In extreme cases, frank patellar dislocation with or without osteochondral fractures may ensue.

Because patellar dislocation reflects an insidious and progressive growth disturbance, nonoperative management relying, on physical therapy and bracing, is of little value. During the adult years, premature and eccentric stress on the knee may result in hypoplasia of the lateral condyle, meniscal tears, articular cartilage attrition, and arthrosis of the anterior and lateral compartments.

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Epidemiology

Frequency

Adolescent idiopathic genu valgum may be familial or it may occur sporadically. The true incidence is unknown. Certainly, it is one of the most common causes of anterior knee pain in teenagers and is a frequent reason for orthopedic consultation. Predisposing syndromes, such as hereditary multiple exostoses, Down syndrome, and skeletal dysplasias, are more apt to manifest in patients aged 3-10 years, and valgus may become severe if untreated. While the angle may not change, as the height increases, the mechanical axis progressively shifts more laterally, manifested by increasing knee pain and/or patellar instability. Regardless of the etiology, surgical correction of significant and symptomatic malalignment is warranted; when required in younger children, the process may need to be repeated as they continue to grow.

In countries where malnutrition is common and access to medical care is limited, the overall incidence of genu valgum is undoubtedly higher. While polio has been largely eradicated, other infectious diseases may result in growth disturbances. Mistreated (or untreated) traumatic injuries cause physeal damage or overgrowth (for example), resulting in progressive and disabling clinical deformity. Likewise, untreated congenital anomalies, skeletal dysplasias, genetic disorders, metabolic conditions, and rheumatologic diseases may cause genu valgum.

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Etiology

It is well recognized that toddlers aged 2-6 years may have physiologic genu valgum. For this age group, typical features include ligamentous laxity, symmetry, and lack of pain or functional limitations. Despite the sometimes-impressive deformities, no treatment is warranted for this self-limiting condition. Bracing is meddlesome and expensive, and shoe modifications are unwarranted. The natural history of this condition is benign; therefore, parents simply need to be educated as to what to expect and when. Annual follow-up until resolution may help to assuage their fears.

In contrast, adolescent idiopathic genu valgum is not benign or self-limiting. Teenagers may present with a circumduction gait, anterior knee pain, and, occasionally, patellofemoral instability. The natural history of this condition may culminate in premature degenerative changes in the patellofemoral joint and in the lateral compartment of the knee. Various other conditions, including postaxial limb deficiencies, genetic disorders such as Down syndrome, hereditary multiple exostoses, neurofibromatosis, and vitamin D–resistant rickets may cause persistent and symptomatic genu valgum. Some of these conditions require team management with other health care providers; however, surgical intervention is still likely to be necessary to correct the malalignment of the knees.

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Pathophysiology

With normal alignment, the physes and epiphyses are subjected to physiologic and intermittent compression and tension and, thus, are shielded from pathologic stress. Balanced growth preserves straight legs, symmetrical limb lengths, and normal function. In genu valgum, as the mechanical axis shifts laterally, pathological stress is placed on the lateral femur and tibia, inhibiting growth and possibly leading to a vicious cycle. Not only is physeal growth inhibited, but also the Hueter-Volkmann effect upon the entire hemi-epiphysis (lateral femoral condyle), preventing its normal expansion. According to the Hueter-Volkmann principle, continuous or excessive compressive forces on the epiphysis have an inhibitory effect on growth. Consequently, growth in the lateral condyle of the femur is suppressed globally, resulting in a shallow femoral sulcus and a propensity for the patella to tilt and subluxate laterally.

During gait, medial thrust of the tibia relative to the femur may compromise the integrity of the restraining medial collateral ligaments, resulting in localized pain and progressive joint laxity.

In addition to knee pain and laxity, patients may develop a circumduction gait, swinging each leg outward to avoid knocking their knees together. This gait pattern is awkward and laborious; the patient is unable to run, ride a bicycle, or participate safely and effectively in play or sports activities, potentially leading to social isolation and possible ridicule. Left untreated, the natural history for this condition is likely to be that of inexorable progression and deterioration.

The lifelong valgus knee presents a daunting challenge to the adult reconstructive orthopedist. Total knee arthroplasty may be fraught with complications, including persistent malalignment, neurovascular compromise, patellar instability, and premature loosening of the prosthetic components. Despite the recent availability of sex-specific total knee components, or patellofemoral arthroplasty, these anatomic problems pose a challenge. Therefore, it is in the best interest of the patient for the clinician to try to prevent such an outcome. Correction of genu valgum and neutralization of the forces across the knee are the goals of early and, if necessary, repeated intervention, which forestalls the need for more invasive adult reconstructive procedures.

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Presentation

It is important to identify and document the natural history of genu valgum. On rare occasions, genu valgum may be noted in the nursery, indicating the presence of some type of localized or generalized skeletal malformation or dysplasia. Congenital lateral dislocation of the patella has been described. The extensor mechanism of the knee is displaced laterally so that every time the child contracts the quadriceps, the knee is flexed (rather than extended) and rotates outward, accentuating the valgus deformity. Another example is postaxial hypoplasia of the limb, sometimes first manifested by the absence of a lateral ray (or 2) of the foot.[8]

More commonly, genu valgum does not become apparent until after the child reaches walking age. A normal variant of the disorder in toddlers (physiologic valgus) typically is symmetrical and pain free, but it should resolve spontaneously by the time the child is aged 6 years. If the valgus is unilateral or symptomatic, referral to an orthopedist and radiographic evaluation are warranted.

Family history may be important because certain heritable conditions, such as hereditary multiple exostoses, Marfan syndrome, osteogenesis imperfecta, or vitamin D–resistant rickets may predispose a patient to this condition.

The physical examination should include assessment of the gait pattern, including the propensity for circumduction, and evaluation of lower extremity lengths. Stature, craniofacial features, the spine, and the upper extremities should be evaluated. Various genetic conditions and skeletal dysplasias may be documented in this manner; consultation with a geneticist may be warranted.

With the child standing, compare the relative limb lengths by leveling the pelvis with blocks and measuring and recording the intermalleolar distance (IMD). Torsional deformities of the femur and/or tibia should be documented. Often, genu valgum is observed in association with outward torsion of the femur, tibia, or both. Look for retropatellar crepitus and tenderness and note patellar tilt, tracking, and stability. For situations other than the aforementioned physiologic genu valgum, medical imaging is warranted.

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Indications

Physiologic genu valgum should be treated expectantly. The family should be educated to avert unnecessary concerns and inappropriate treatment. Bracing and corrective shoes are ineffective, and physical therapy is of no benefit. Pathologic genu valgum warrants aggressive treatment to alleviate symptoms and prevent progression. Bracing and therapy are inadequate to meet these goals. Surgical intervention is the only successful intervention for correcting the problem. Surgical options include osteotomy or growth manipulation (hemiepiphysiodesis).

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Relevant Anatomy

The radiographic parameters relevant to defining genu valgum are best measured on a full length, standing, anteroposterior (AP) radiograph of the legs. The angle is measured between the femoral shaft and its condyles (the normal angle is 84°); this is referred to as the lateral distal femoral angle. The other relevant angle is the proximal medial tibial angle; this is the angle between the tibial shaft and its plateaus (the normal angle is 87°). The mechanical axis is a straight line drawn from the center of the femoral head to the center of the ankle; this should bisect the knee. Allowing for variations of normal, an axis within the 2 central quadrants (zones +1 or -1) of the knee is deemed acceptable.

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Contraindications

Physeal closure, whether it be due to local trauma or to skeletal maturity, is the sole contraindication to using guided growth for deformity correction. Obviously, this technique cannot be used after skeletal maturity, when the only option is a corrective osteotomy. In some cases, malrotation actually improves or is resolved as the mechanical axis is restored to neutral; therefore, rotational osteotomies may be reserved for patients who are still troubled by unresolved malrotation. Likewise, lengthening (along the anatomic axis) may be reserved for children who ultimately require limb length equalization.

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Contributor Information and Disclosures
Author

Peter M Stevens, MD Professor, Director of Pediatric Orthopedic Fellowship Program, Department of Orthopedics, University of Utah School of Medicine

Peter M Stevens, MD is a member of the following medical societies: Pediatric Orthopaedic Society of North America, Alpha Omega Alpha, American Academy of Orthopaedic Surgeons, American Orthopaedic Association

Disclosure: Received royalty from Orthofix Inc for independent contractor; Received royalty from Orthopediatrics, Inc for independent contractor; Received honoraria from Orthopediatrics, Inc for speaking and teaching.

Coauthor(s)

Michael C Holmstrom, MD Consulting Surgeon, Department of Orthopedics, The Orthopedic Specialty Hospital (TOSH)

Michael C Holmstrom, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, Arthroscopy Association of North America, Pediatric Orthopaedic Society of North America, American Medical Association, Utah Medical Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

George H Thompson, MD Director of Pediatric Orthopedic Surgery, Rainbow Babies and Children’s Hospital, University Hospitals Case Medical Center, and MetroHealth Medical Center; Professor of Orthopedic Surgery and Pediatrics, Case Western Reserve University School of Medicine

George H Thompson, MD is a member of the following medical societies: American Orthopaedic Association, Scoliosis Research Society, Pediatric Orthopaedic Society of North America, American Academy of Orthopaedic Surgeons

Disclosure: Received none from OrthoPediatrics for consulting; Received salary from Journal of Pediatric Orthopaedics for management position; Received none from SpineForm for consulting; Received none from SICOT for board membership.

Chief Editor

Dennis P Grogan, MD Clinical Professor (Retired), Department of Orthopedic Surgery, University of South Florida College of Medicine; Orthopedic Surgeon, Department of Orthopedic Surgery, Shriners Hospital for Children of Tampa

Dennis P Grogan, MD is a member of the following medical societies: American Medical Association, American Orthopaedic Association, Scoliosis Research Society, Irish American Orthopaedic Society, Pediatric Orthopaedic Society of North America, American Academy of Orthopaedic Surgeons, American Orthopaedic Foot and Ankle Society, Eastern Orthopaedic Association

Disclosure: Nothing to disclose.

Additional Contributors

Mininder S Kocher, MD, MPH Associate Professor of Orthopedic Surgery, Harvard Medical School/Harvard School of Public Health; Associate Director, Division of Sports Medicine, Department of Orthopedic Surgery, Children's Hospital Boston

Mininder S Kocher, MD, MPH is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American College of Sports Medicine, Pediatric Orthopaedic Society of North America, American Association for the History of Medicine, American Orthopaedic Society for Sports Medicine, Massachusetts Medical Society

Disclosure: Received consulting fee from Smith & Nephew Endoscopy for consulting; Received consulting fee from EBI Biomet for consulting; Received consulting fee from OrthoPediatrics for consulting; Received stock from Pivot Medical for consulting; Received consulting fee from pediped for consulting; Received royalty from WB Saunders for none; Received stock from Fixes-4-Kids for consulting.

References
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  2. Stevens PM, Novais EN. Multilevel guided growth for hip and knee varus secondary to chondrodysplasia. J Pediatr Orthop. 2012 Sep. 32(6):626-30. [Medline].

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  7. Burghardt RD, Herzenberg JE, Standard SC, Paley D. Temporary hemiepiphyseal arrest using a screw and plate device to treat knee and ankle deformities in children: a preliminary report. J Child Orthop. 2008 Jun. 2(3):187-97. [Medline].

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  9. Guzman H, Yaszay B, Scott VP, Bastrom TP, Mubarak SJ. Early experience with medial femoral tension band plating in idiopathic genu valgum. J Child Orthop. 2011 Feb. 5(1):11-7. [Medline]. [Full Text].

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  11. Blair VP 3rd, Walker SJ, Sheridan JJ, Schoenecker PL. Epiphysiodesis: a problem of timing. J Pediatr Orthop. 1982 Aug. 2(3):281-4. [Medline].

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  14. Bowen JR, Johnson WJ. Percutaneous epiphysiodesis. Clin Orthop. 1984 Nov. (190):170-3. [Medline].

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  16. Gabriel KR, Crawford AH, Roy DR, et al. Percutaneous epiphyseodesis. J Pediatr Orthop. 1994 May-Jun. 14(3):358-62. [Medline].

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  20. Koshino T. Osteotomy around young deformed knees: 38-year super-long-term follow-up to detect osteoarthritis. Int Orthop. 2009 Sep 24. [Medline].

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  22. Liotta FJ, Ambrose TA 2nd, Eilert RE. Fluoroscopic technique versus Phemister technique for epiphysiodesis. J Pediatr Orthop. 1992 Mar-Apr. 12(2):248-51. [Medline].

  23. Little DG, Nigo L, Aiona MD. Deficiencies of current methods for the timing of epiphysiodesis. J Pediatr Orthop. 1996 Mar-Apr. 16(2):173-9. [Medline].

  24. Métaizeau JP, Wong-Chung J, Bertrand H, Pasquier P. Percutaneous epiphysiodesis using transphyseal screws (PETS). J Pediatr Orthop. 1998 May-Jun. 18(3):363-9. [Medline].

  25. Mast, N, Brown N, Stevens, P. Validation of a Genu Valgum Model in a Rabbit Hind Limb. Journal of Pediatric Orthopaedics. April/May 2008. 28:375-380.

  26. Mielke CH, Stevens PM. Hemiepiphyseal stapling for knee deformities in children younger than 10 years: a preliminary report. J Pediatr Orthop. 1996 Jul-Aug. 16(4):423-9. [Medline].

  27. Phemister D. Operative arrestment of longitudinal growth of bones in the treatment of bones in the treatment of deformities. J Bone Joint Surg Am. 1933. 15:1-15.

  28. Salenius P, Vankka E. The development of the tibiofemoral angle in children. J Bone Joint Surg Am. 1975 Mar. 57(2):259-61. [Medline].

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  30. Stevens PM, MacWilliams B, Mohr RA. Gait analysis of stapling for genu valgum. J Pediatr Orthop. 2004 Jan-Feb. 24(1):70-4. [Medline].

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  32. Stevens, P, Klatt, J. Guided Growth for Fixed Knee Flexion Deformity. Journal of Pediatric Orthopaedics. Sept. 2008. 28:632-639.

 
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This diagram depicts genu valgum involving the right leg (lighter shade), where the mechanical axis falls outside the knee. The goal of treatment is to realign the limb and neutralize the mechanical axis (dotted red line), thereby mitigating the effects of gravity through guided growth of the femur and/or tibia (whatever is required to maintain a horizontal knee joint axis). The darker shade depicts normal alignment with the mechanical axis now bisecting the knee.
This 9-year-old patient has symmetrical and progressive genu valgum caused by a hereditary form of metaphyseal dysplasia. One method of treatment is to undertake bilateral femoral and tibial/fibular osteotomies, securing these with internal plates or external frames. However, the hospitalization and the attendant cost and risks, including peroneal nerve palsy and compartment syndrome, make this a daunting task for the surgeon and family alike. Furthermore, mobilization and weightbearing may require physical therapy but must be delayed pending initial healing of the bones.
Heretofore, stapling was a viable option. This outpatient procedure permitted simultaneous and multiple deformity correction, without casts or delayed weightbearing. However, the concept of compressing and overpowering the physes has the drawbacks of slower correction because the fulcrum is within the physis. Provided the rigid staples did not dislodge or fatigue, satisfactory correction could be realized. If the hardware failed prematurely, the correction was either abandoned or the hardware exchanged. Compared with osteotomies, it was a risk worth taking, that is, until the advent of a better option.
The application of a single 8-plate per physis permits the same correction as stapling, without the potential drawbacks of implant migration or fatigue failure. Based on the principle of facilitating rather than compressing the physes, the correction occurs more rapidly and rebound growth, though possible, may be less frequent. When the mechanical axis has been restored to neutral, the plates (or metaphyseal screws) are removed (and replaced as necessary if recurrent deformity ensues).
This 14-year-old boy, weighing 132 kg, presented with activity-related anterior knee pain, circumduction gait, and difficulty with running and sports. His symptoms had been progressive over a period of 18 months despite nonoperative measures including physical therapy, activity restrictions, and nonsteroidal anti-inflammatory drug therapy.
Nine months following the insertion of 8-plates in the distal femora (1 per knee), the mechanical axis is approaching neutral and his symptoms abated. The plates were removed 2 months later, allowing for full correction of his valgus deformities. He has not had recurrence.
This 14-year-old boy broke his distal femur 1 year previously. He was treated with internal fixation using a condylar plate, and the fracture healed uneventfully. However, he developed medial overgrowth of the femur, which caused progressive and painful genu valgum. Note the lateral displacement of the mechanical axis into zone 2. One alternative is to perform a supracondylar osteotomy with exchange of the plate; this was declined.
Two options for instrumented and reversible hemi-epiphysiodesis are multiple staples versus a tension band plate. The latter, being flexible yet secure, avoids the potential risks of hardware breakage or migration. Furthermore, growth is facilitated rather than restricted and the alignment is restored more rapidly.
One year following guided growth of the femur with an 8-plate, his mechanical axis is neutral, his limb lengths are equal, and his symptoms have abated; the plate was then removed. Neither procedure required hospitalization or immobilization. Each time he was able to rapidly resume sports participation.
A 17-year-old male who underwent an arthroscopic reconstruction of his left anterior cruciate ligament utilizing braided semitendinosis 1 year prior to this film. With ensuing growth he developed progressive genu valgum with medial and anterior knee pain and difficulty running.
A fluoroscopic close-up view of the left knee demonstrates, despite his chronologic age of 17, that he has significant growth remaining. (Note arrows pointing to the physis = growth plate). It was felt that the most expedient and safe treatment would be guided growth. Considering his relative skeletal maturity, it was elected to apply tension band plates to the femur and tibia simultaneously, for the sake of time.
The patient's legs are straight 11 months following pan-genu guided growth of the medial femur and tibia. His pain has resolved and he has resumed a fully active lifestyle. His limb lengths are equal and his knee remains stable.
A standing AP radiograph of the legs confirms the clinical findings; the plates were therefore removed.
This 6-year-old girl, born with tibial dysplasia, underwent foot ablation at age 2 years, combined with surgical synostosis of the distal fibula to the tibial stump. She developed progressive genu valgum necessitating that the prosthetist move the post medially. However, she then experienced medial knee pain and stump irritation. This full-length weight-bearing radiograph demonstrates lateral displacement of the mechanical axis (red dotted line) to the joint margin.
Treatment options are limited to osteotomy or guided growth. An osteotomy would require "down time" - out of her prosthesis and non weight-bearing while the cut bone is healing.
The family chose the option of guided growth, and plates were applied to the distal medial femur and proximal medial tibia. She resumed full activities in her prosthesis and this full-length radiograph, taken one year later, demonstrates normalization of the mechanical axis. At this point the prosthetist moved her post laterally. Her knee pain and stump irritation have abated.
A close-up view demonstrating the neutral mechanical axis and open growth plates. Note the divergence of the screws. At this point, the plate was removed. Further growth will be monitored, repeating guided growth if needed.
A clinical photograph showing her alignment just prior to hardware removal.
 
 
 
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