summary Adolescent Blount's Disease is a progressive, pathologic genu varum centered at the tibia in children > 10 years of age. Diagnosis is made clinically with presence of a genu varum deformity and confirmed radiographically with an increased metaphyseal-diaphyseal angle. Treatment is generally surgical epiphysiodesis or osteotomy depending on severity of deformity and amount of growth left. Epidemiology Risk factors obesity African-American descent Etiology Blount's disease is best divided into two distinct disease entities Infantile Blount's pathologic genu varum in children 2-5 years of age more common deformity rarely from femur typically affects both lower extremities Adolescent Blount's (this topic) pathologic genu varum in children > 10 years of age more likely to have femoral deformity less common less severe more likely to be unilateral Pathophysiology Blount's is thought to be caused by a dyschondrosis of medial physis of proximal tibia likely multifactorial but related to mechanical overload in genetically susceptible individuals Classification Infantile vs. Adolescent Blounts Infantile Blounts Adolescent Blounts Age 2-5yrs >10yrs Bilaterality 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 Location Physeal/epiphyseal Metaphyseal 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 hallmark is genu varum deformity obesity usually unilateral (compared to bilateral in infantile Blount's) limb-length discrepancy secondary to deformity mild to moderate laxity of medial collateral ligament Imaging Radiographs views standing long-cassette AP radiograph of both lower extremities ensure patellas are facing forward (commonly associated with internal tibial torsion) findings suggestive of adolescent Blount's disease narrowing of the tibial epiphysis widening of the medial tibial growth plate occasional widening of the lateral distal femoral physis metaphyseal beaking less commonly seen with adolescent Blount's measurements metaphyseal-diaphyseal angle (Drennan) login to view 2 more bullets tibiofemoral angle login to view 1 more bullet Treatment Nonoperative observation or bracing is unlikely to be successful - treatment is always surgical indications login to view 1 more bullet outcomes login to view 2 more bullets Operative lateral tibia and fibular epiphysiodesis indications login to view 1 more bullet outcomes login to view 1 more bullet proximal tibia/fibula osteotomy indications login to view 3 more bullets outcomes login to view 1 more bullet distal femoral osteotomy or epiphysiodesis indications login to view 1 more bullet Techniques Lateral tibia and fibular epiphysiodesis transient hemiepiphysiodesis technique login to view 2 more bullets pros login to view 3 more bullets cons login to view 10 more bullets permanent hemiepiphysiodesis technique login to view 1 more bullet pros login to view 3 more bullets cons login to view 2 more bullets Proximal tibia/fibula osteotomy goals of correction overcorrection to valgus not indicated (as is the case in infantile Blount's) strive for neutral mechanical axis high tibial osteotomy with rigid internal fixation technique login to view 2 more bullets post-op login to view 1 more bullet pros login to view 1 more bullet cons login to view 3 more bullets osteotomy with external fixation and gradual correction technique login to view 2 more bullets post-op login to view 1 more bullet pros login to view 2 more bullets cons login to view 3 more bullets