Solitary overgrowth is most commonly associated with chronic inflammation or chronically increased blood flow.
Periarticular osteopenia, erosions at the margins of joints, synovial hypertrophy, subchondral cysts and sclerosis, joint space narrowing.
The knee is the most commonly affected large joint.
Pus or organisms on arthrocentesis.
Although acute bacterial infections are usually rapidly destructive and thus tend not to alter epiphy-seal growth, infantile osteomyelitis may accelerate development of the affected epiphysis.
The femoral head is enlarged (coxa magna) and the epiphysis is flattened and deformed from AVN.
Coxa magna develops during the reparative stage.
Status post hip dislocation
Coxa magna with normal architecture.
Accelerated growth of the affected side occurs after successful relocation of a previously small proximal femoral epiphysis. Necrosis of the femoral head is more common than coxa magna.
Soft-tissue swelling, periarticular osteopenia, epiphyseal overgrowth. Later stages progress to joint space narrowing, marginal osteophyte formation. Synovium is decreased in T1- and T2-weighted signal intensity on MRI.
Small medial tibial plateau with hypertrophy of the medial femoral condyle (Kosovicz sign).
Short stature, shortening of the fourth metacar-pals, radiocarpal angulation, cervical ribs, Scheuer-mann disease, Madelung deformity.
Large proximal femoral epiphyses with broad metaphyses and short femoral neck.
Mild form of short-limbed dwarfism. Between the spectrum of achondroplasia to normal. Spinal stenosis.
Increased incidence of embryonal tumors, Wilms tumor, neuroblastoma, and hepatoblastoma.
Uneven enlargement of the parts of the affected limb, including the epiphysis.
Triad of unilateral capillary hemangioma, v arices, and localized gigantism with overgrowth of the skeleton and soft tissues.
Tibia vara (Blount disease)
Unilateral enlargement of the distal femoral epiphysis (medal or lateral condyle).
Overgrowth in distal femur may be in response to changes in the proximal tibia.
Neurofibromatosis and other phakomatoses
Digits > other parts of the extremities.
Metaphyseal chondrodysplasia, Schmid type
Affects proximal femoral epiphyses in 75% of patients. Irregular metaphyses resemble rickets.
Short-limbed dwarfism with a large degree of genu valgum from the age of 2 y.
Dysplasia epiphysealis hemimelica (Trevor disease)
Fig. 5.46a–c, p. 526
(see Table 5.68 )
Advanced skeletal maturation. Premature closure of cranial sutures. Brachydactyly.
Epiphyses are enlarged but normal in shape.
Accelerated skeletal growth with delay in closure of growth plates. Widened joint spaces from increased amount of cartilage. Spadelike appearance of hands and feet.
Polyostotic fibrous dysplasia with precocious puberty (McCune-Albright syndrome)
Multifocal fibrous dysplasia. Advanced bone age, pathologic fractures, and pseudarthrosis.
Triad of fibrous dysplasia, precocious puberty in girls, skin pigmentation mainly in the trunk and proximal limbs. Two to three percent of patients with fibrous dysplasia. Bone involvement tends to be asymmetric.
Fig. 5.23, p. 511
Large epiphyses at the knees, large flattened proximal femoral epiphyses with broad metaphyses.
Spondyloepiphyseal dysplasia associated with deafness or myopia.