Page 24 - Slipped Capital Femoral Epiphysis Pathogenetic and Clinical aspects

Chapter 2
miniature swine. They harvested the hind limb proximal femoral physis at 25 weeks. Compared to the two controls the two hypothyroid swine showed disorganization and widening of the physis and loss of chondrocyte columns and cells. Also the swine gene expression showed inhibition of type 2 and 10 collagen and aggrecan, similar to the human physis in SCFE.
In conclusion, the physis in SCFE shows histological differences compared to normal physes in columnar organisation, on a cellular level and in the extra cellular matrix. The fundamental problem is that the role of these described changes is unknown. It is unclear whether they are causal or adaptive. Some of these changes can also occur as endocrine or metabolic abnormalities.
Diagnosis.
Primary healthcare providers are often unfamiliar with SCFE and do not recognize this hip problem in adolescents, thereby delaying the diagnosis which results in severe consequences. A previous study described an average duration of 5 months before symptoms occur and SCFE can be diagnosed [69]. Of the patients with acute/unstable SCFE, 88% have antecedent symptoms more than a month in advance. Early diagnosis is critical to prevent a morbid, unstable SCFE [78]. Clinical examination often reveals a limp and localized pain in the groin, hip, thigh or knee. On physical examination, decreased internal rotation and flexion of the slipped hip joint is found. The sign of Drehmann, which features external rotation and abduction when flexing the hip, is related to the existence of femoral acetabular impingement [52].
Actual diagnosis of SCFE is confirmed by radiographic examination. Detection of the subtle signs of early SCFE from an anteroposterior (AP) radiograph of the pelvis requires a trained eye. The `metaphyseal blanch sign` is an overprojection on the anteroposterior radiograph of the femoral head epiphysis slipping posteriorly of the metaphysis. The Klein’s line is a line drawn over the superior part of the neck and is supposed to intersect the epiphysis of the head on the AP radiograph. In SCFE, however, this Klein’s line does not intersect the epiphysis, or show a difference in the maximal width between the epiphysis compared to the opposite site in unilateral disease. [39, 50, 106]. Its sensitivity is mainly limited in the valgus, and in mild and moderate slips [106].
Another diagnostic can be found on an AP radiograph of the pelvis; part of the inferior metaphysis is normally projected over the posterior cortex of the acetabulum, which has disappeared in SCFE. A new pathognomic finding has been
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