summary Developmental Coxa Vara is a rare condition that causes a decreased neck-shaft angle that is associated with an ossification defect in inferior femoral neck. Diagnosis can be confirmed with plain radiographs of the hip. Treatment can be nonoperative or surgical corrective valgus derotation osteotomy depending on patient symptoms, the severity of varus deformity, and degree of angle progression. Epidemiology Incidence 1 in 25,000 live births in the US Demographics males and females affected equally presents between age of ambulation and 6 years of age Anatomic location bilateral in 1 in 3 cases Risk factors congenital defects differential diagnosis trauma SCFE Legg-Calve-Perthes Etiology Pathophysiology proximal femoral cartilaginous physis or ossification center defects lead to decreased proximal femoral neck-shaft angle vertical position of the proximal femoral physis and varus pathomechanics coxa vara and vertical physis increases login to view 2 more bullets Genetics no clear inheritance pattern Associated conditions femoral neck stress fractures decreased limb length early hip osteoarthritis Classification Etiologies of Coxa Vara developmental congenital (e.g. congenital short femur, PFFD) acquired (e.g. SCFE, infection, Perthes) dysplasia (e.g OI, Jansen, Schmid, SED) cretinism Presentation History previous hip trauma or infection associated skeletal abnormalities prenatal and developmental history family history of similar deformity Symptoms usually painless gait abnormality waddling or limp (trendelenburg gait) login to view 1 more bullet Physical exam inspection leg length discrepancy high riding greater trochanter limb shortening excessive lumbar lordosis motion restricted hip range of motion in all planes that is usually non-tender Imaging Radiographs recommended views: AP hip with limb internally rotated + lateral hip findings varus neck shaft angle <120 degrees short femoral neck, vertical physis increased Hilgenreiner's epiphyseal angle (normal <25 degrees) login to view 1 more bullet triangular metaphyseal fragment in inferior femoral neck (looks like inverted-Y radiolucency) decreased femoral anteversion CT indications surgical planning delineate proximal femur defects orientation of deformity views consider all views including 3D reconstructions findings deformity configuration bone stock physeal widening Treatment Nonoperative observation alone indications login to view 4 more bullets Operative corrective valgus derotation osteotomy (VDRO) indications login to view 3 more bullets aftercare login to view 1 more bullet Technique Corrective valgus derotation osteotomy (VDRO) goals over-correct neck shaft angle (literature suggests to reduce Hilgenreiner's physeal angle < 38°) correct leg length discrepancy correct hip anteversion/retroversion re-establish abductor muscle tensioning approach typically a hip direct lateral approach is used procedure(s) valgus trochanteric osteotomy – may fix with blade plate login to view 7 more bullets greater trochanter epiphyseodesis login to view 4 more bullets greater trochanter transfer login to view 5 more bullets Complications Loss of correction Premature closure of the proximal femoral physis Overgrowth of proximal femur Dysplasia of acetabulum