Weight-bearing anteroposterior and lateral radiographs of both legs are necessary for the diagnosis of tibia vara. Fragmentation, wedging, and beak deformities of the proximal medial tibia are the major radiologic features of infantile Blount disease. In late-onset Blount disease, the medial deformity may not be as readily noticeable. It can be very difficult to tell the difference between physiologic genu varum and infantile Blount disease on radiographs in patients younger than 2 years of age.
Once the diagnosis of Blount disease is confirmed, treatment should begin immediately. Orthotics to unload the medial compressive forces can be used in children younger than 3 years of age with a mild deformity. Compliance with this regimen can be difficult. Nonoperative management of more severe Blount disease is contraindicated. Any patient older than 4 years should undergo surgical intervention. Patients with moderate to severe deformity and patients who fail orthotic treatment also require surgical intervention. Proximal tibial valgus osteotomy with fibular diaphyseal osteotomy is the usual procedure performed.
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In-Toeing, Out-Toeing, and Toe-Walking
Leg-length discrepancy (LLD) is common and may be due to differences in the femur, tibia, or both bones. The differential diagnosis is extensive, but common causes are listed in Table 200-2. The majority of the lower extremity growth comes from the distal femur (38%) and the proximal tibia (27%).
Clinical measurements using bony landmarks (anterior superior iliac spine to medial malleolus) are inaccurate. The teloradiograph is a single radiograph of both legs that can be done in very young children. The orthoradiograph consists of three slightly overlapping exposures of the hips, knees, and ankles. The scanogram consists of three standard radiographs of the hips, knees, and ankles with a ruler next to the extremities. A
Developmental Developmental dysplasia of the hip (DDH) Legg-Calve-Perthes disease (LCPD)
Neuromuscular Hemiplegia Disuse secondary to developmental delay
Infectious Physeal injury secondary to osteomyelitis
Tumors Fibrous dysplasia Physeal injury secondary to irradiation or neoplastic infiltration Overgrowth
Trauma Physeal injury with premature closure Malunion (shortening of extremity) Overgrowth of healing fracture computed tomography (CT) scanogram is the most accurate measure of LLD, but also has the highest radiation exposure. Technology such as EOS/slot scanning is an extremely accurate, reduced-radiation alternative to CT scan. The measured discrepancy is followed using Moseley and Green-Anderson graphs.
Treating LLD is complex. The physician must take into account the estimated adult height, discrepancy measurements, skeletal maturity, and the psychological aspects of the patient and family. LLD greater than 2 cm usually requires treatment. Shoe lifts can be used, but they will often cause psychosocial problems for the child and may make the shoes heavier and less stable. Surgical options include shortening of the longer extremity, lengthening of the shorter extremity, or a combination of the two procedures. Discrepancies less than 5 cm are treated by epiphysiodesis (surgical physeal closure) of the affected side, whereas discrepancies greater than 5 cm are treated by lengthening. Current use of removable implants, which permit growth modulation without permanent impact on growth plates, has allowed for early and more accurate treatment.
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The knee joint is constrained by soft tissues rather than the usual geometric fit of articulating bones. The medial and lateral collateral ligaments as well as the anterior and posterior cruciate ligaments maintain knee stability. Weight and force transmission can cross articular cartilage and the meniscus.
Pull of vastus lateralis           vastus intermedialis           rectus femoris
Femur Pull of vastus medialis PATELLA Pull of patellar tendon