summary Infantile Blount's disease is progressive pathologic genu varum centered at the tibia in children 2 to 5 years of age. Diagnosis is suspected clinically with presence of a genu varum/flexion/internal rotation deformity and confirmed radiographically with an increased metaphyseal-diaphyseal angle. Treatment ranges from bracing to surgery depending on patient age, severity of deformity, and presence of a physeal bar. Epidemiology Risk factors overweight children early walkers (< 1 year) Hispanic and African American Etiology Best divided into two distinct disease entities Infantile Blount's(this topic) pathologic genu varum in children 2 to 5 years of age male > female more common bilateral in 50% Adolescent Blount's pathologic genu varum in children > 10 years of age less common less severe more likely to be unilateral Pathophysiology likely multifactorial but related to mechanical overload in genetically susceptible individuals including excessive medial pressure produces an osteochondrosis of the medial proximal tibial physis and epiphysis osteochondrosis can progress to a physeal bar Anatomy Genu varum is a normal physiologic process in children physiologic genu varum genu varum (bowed legs) is normal in children less than 2 years genu varum migrates to a neutral at ~ 14 months continues on to a peak genu valgum (knocked knees) at ~ 3 years of age genu valgum then migrates back to normal physiologic valgus at ~ 7 years of age Classification Langenskiold Classification type I thru IV consist of increasing medial metaphyseal beaking and sloping type V and VI have an epiphyseal-metaphyseal bony bridge (congenital bar across physis) provides prognostic guidelines Infantile versus Adolescent Blount's Infantile Blounts Adolescent Blounts Age 2-5yrs >10yrs Bilaterally 50% bilateral Usually unilateral Risks Early walking, large stature, obesity Obesity Classification Langenskiold No radiographic classification Severity More severe physeal/ epiphyseal disturbance Less severe physeal/ epiphyseal disturbance Bone Involvement Proximal medial tibia physis, producing genu varus, flexion, internal rotation, AND may have compensatory distal femoral VALGUS Proximal tibia physis, AND may have distal femoral VARUS and distal tibia valgus Natural History Self-limited - stage II and IV can exhibit spontaneous resolution Progressive, never resolves spontaneously (thus bracing unlikely to work) Treatment options Bracing and surgery Surgery only Presentation Physical exam genu varum/flexion/internal rotation deformity usually bilateral in infants may exhibit positive 'cover-up test' often associated with internal tibial torsion leg length discrepancy usually NO tenderness, restriction of motion, effusion lateral thrust on walking Imaging Radiographs views ensure that patella are facing forwards for evaluation (commonly associated with internal tibial torsion) findings suggestive of Blounts disease varus focused at proximal tibia severe deformity asymmetric bowing medial and posterior sloping of proximal tibial epiphysis progressing deformity sharp angular deformity lateral thrust during gait metaphyseal beaking different than physiologic bowing which shows a symmetric flaring of the tibia and femur measurements metaphyseal-diaphyseal angle (Drennan) angle between line connecting metaphyseal beaks and a line perpendicular to the longitudinal axis of the tibia >16 ° is considered abnormal and has a 95% chance of progression Drennan angles between 11-16° necessitate close observation for the progression of tibia vara <10 ° has a 95% chance of natural resolution of the bowing tibiofemoral angle angle between the longitudinal axis of the femur and tibia Differential The following conditions can also lead to pathologic genu varum persistent physiological varus rickets osteogenesis imperfecta MED SED metaphyseal dysostosis (Schmidt, Jansen) focal fibrocartilaginous defect thrombocytopenia absent radius proximal tibia physeal injury (radiation, infection, trauma) Treatment Nonoperative brace treatment with KAFO indications Stage I and II in children < 3 years technique bracing must continue for approximately 2 years for resolution of bony changes outcomes improved outcomes if unilateral poor results associated with obesity and bilaterality if successful, improvement should occur within 1 year Operative proximal tibia/fibula valgus osteotomy overcome the varus/flexion/internal rotation deformity indications Stage I and II in children > 3 years Stage III, IV, V, VI age ≥ 4y (all stages) failure of brace treatment progressive deformity metaphyseal-diaphyseal angles > 20 degrees technique perform osteotomy below tibial tubercle staged procedures may be required for Stage IV, V, VI epiphysiolysis required in stage V and VI outcomes risk of recurrence is significantly lessened if performed before 4 years of age growth modulation technique tension band plate and screws physeal bar resection indication at least 4y of growth remaining technique perform together with osteotomy interpositional material is usually fat or PMMA hemiplateau elevation technique may be performed together with osteotomy Techniques Proximal tibia/fibula valgus osteotomy goals of correction overcorrect into 10-15° of valgus because medial physeal growth abnormalities persist distal segment is fixed in valgus, external rotation and lateral translation technique staples and plates function by increasing compression forces across the physis which slows longitudinal growth (Heuter-Volkmann principle) temporary lateral physeal growth arrest with staples or plates can be used increasing use for correction in younger patients include a bar resection (epiphysiolysis) when a physeal bar is present (Langenskiold V and VI) consider hemiepiphysiodesis if bar > 50% medial tibial plateau elevation is required at time of osteotomy if significant depression is present consider prophylactic anterior compartment fasciotomy Complications Compartment syndrome (with high tibial/fibular osteotomy) prophylactic release of anterior compartment Recurrence of tibial vara severe cases of Infantile Blount's disease may develop a physeal bar can result in progressive varus after a well executed proximal tibial valgus osteotomy may require a lateral tibial hemiepiphysiodesis or bar resection Prognosis Best outcomes with early diagnosis and unloading of the medial joint with either bracing or an osteotomy Young children with stage II and stage IV can have spontaneous correction
QUESTIONS 1 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ13.171) A 17-month-old boy is referred to your office for abnormal gait. He began walking at 15 months of age. His mother reports that he has always had bowed legs, but the deformity has steadily worsened. A video of the child's gait is shown in Video V. What is the most appropriate next step in management? QID: 4806 FIGURES: V Type & Select Correct Answer 1 Observation 10% (377/3603) 2 Bracing 8% (288/3603) 3 Standing, full-length bilateral lower extremity radiographs 78% (2823/3603) 4 Bilateral knee MRIs 0% (8/3603) 5 Bilateral proximal tibial osteotomies 2% (85/3603) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ08.124) A 32-month-old male with severe infantile Blounts disease has been treated with full time bracing for the past year. At most recent follow-up, the varus deformity of his bilateral legs has worsened despite compliance with bracing. What treatment is now recommended? QID: 510 Type & Select Correct Answer 1 Observation, discontinuation of bracing 4% (121/2741) 2 Observation, continuation of full-time bracing 15% (400/2741) 3 Bilateral proximal tibial osteotomies 67% (1828/2741) 4 Bilateral distal femur osteotomies 3% (89/2741) 5 Bilateral proximal tibial medial hemiepiphysiodesis 11% (293/2741) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ08.183) Lateral tibial physeal stapling is a treatment option for adolescent Blount’s disease. How is the staple an example of the Hueter-Volkmann principle? QID: 569 Type & Select Correct Answer 1 Increased compression along the growth plate slows longitudinal growth 85% (1869/2202) 2 Decreased compression along the growth plate slows longitudinal growth 2% (48/2202) 3 Increased tension along the growth plate slows longitudinal growth 8% (177/2202) 4 Decreased tension along the growth plate slows longitudinal growth 3% (70/2202) 5 Increased compression along the plate increases longitudinal growth 1% (27/2202) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07PE.69) Figure 29 shows the AP radiograph of a 14-year-old boy. The radiographic findings are most consistent with what pathologic process? QID: 6129 FIGURES: A Type & Select Correct Answer 1 Septic arthritis 2% (5/321) 2 Hemophilia 2% (8/321) 3 Juvenile rheumatoid arthritis (JRA) 3% (9/321) 4 Adolescent Blount’s disease 48% (155/321) 5 Infantile Blount’s disease 44% (142/321) L 3 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07PE.20) Examination of an obese 3-year-old girl reveals 30 degrees of unilateral genu varum. A radiograph of the involved leg with the patella forward is shown in Figure 10. Management should consist of QID: 6080 FIGURES: A Type & Select Correct Answer 1 continued observation until skeletal maturity. 4% (10/226) 2 fitting for a valgus-producing hinged knee-ankle-foot orthosis. 27% (62/226) 3 lateral proximal tibial hemiepiphysiodesis. 23% (52/226) 4 proximal tibiofibular osteotomy and acute correction. 40% (91/226) 5 proximal tibiofibular epiphysiodesis and osteotomy with lengthening. 3% (7/226) N/A Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ05.185) A healthy 5-year-old boy is referred to your office for leg bowing. Radiographs of his legs are shown in Figure A. Which of the following is the next best step in management? QID: 1071 FIGURES: A Type & Select Correct Answer 1 Observation and 6 month follow-up 19% (286/1469) 2 Nighttime bracing with knee-ankle-foot orthoses 16% (241/1469) 3 Serial casting 4% (61/1469) 4 Bilateral proximal tibial medial hemiepiphysiodesis 6% (83/1469) 5 Bilateral proximal tibial lateral epiphysiodesis using extraperiosteal plates 54% (787/1469) L 4 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (OBQ05.23) A 30-month-old boy has worsening bilateral bowleg deformities, and radiographs depicting Langenskiold stage II are shown in Figure A. The most appropriate initial management should consist of which of the following? QID: 60 FIGURES: A Type & Select Correct Answer 1 Observation 21% (451/2139) 2 Bracing with knee-ankle-foot orthoses 64% (1364/2139) 3 Bracing with ankle-foot orthoses 2% (36/2139) 4 Proximal tibia/fibula valgus osteotomy with bar resection 6% (119/2139) 5 Proximal tibia/fibula valgus osteotomy with hemiepiphysiodesis 7% (155/2139) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (SBQ04PE.3) A valgus producing proximal tibial osteotomy with 10 degrees of overcorrection is the most appropriate treatment for which of the following patients with tibia vara? QID: 2188 Type & Select Correct Answer 1 A 4-year-old obese child with Blount's disease, Langenskiöld stage IV 71% (654/923) 2 An 18-month-old child with a proximal tibia metaphyseal-diaphyseal angle of 11 degrees 1% (11/923) 3 A 2-year-old obese child with Blount's disease, Langenskiöld stage II disease 5% (44/923) 4 A 5-year-old child with untreated renal osteodystrophy and a proximal tibia metaphyseal-diaphyseal angle of 16 degrees 10% (88/923) 5 A 8-year-old child with distal femoral varus and a lateral distal femoral angle of 95 degrees 12% (113/923) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic
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