Page 115 - Slipped Capital Femoral Epiphysis Pathogenetic and Clinical aspects

Introduction
The long-term prognosis of slipped capital femoral epiphysis (SCFE) is largely influenced by the residual deformity, which in turn is related to the extent of slip. One of the methods for classifying the extent of slip is the Southwick classification [1, 2] which, based on lateral head shaft angle, places slip into one of three categories: mild (<30°), moderate (30–60°) and severe (>60°). The femoral head is mostly displaced medially and posteriorly. This displacement causes the metaphysis to move upward and laterally in relation to the femoral head, possibly resulting in anterior impingement with flexion of the hip [3] (Fig. 1a, b). It is thought that repetitive early mechanical abrasion of the prominent metaphysis against the anterior rim of the acetabular cartilage can trigger osteoarthritis [4, 5]. Patients with mild SCFE (<30°) have good prognoses, but patients with moderate and severe SCFE have an increased chance of developing osteoarthritis [6-8].
Fig. 1.
Pre-operative slipped capital femoral epiphysis (SCFE)
Slipped Capital Femoral Epiphysis
The primary objective of SCFE treatments is stopping further slippage, chondrolysis and avascular necrosis (AVN). The choice of treatment is also influenced by the stability of the slip, as described by Loder [9]. In cases of unstable SCFE, most surgeons perform an early gentle reduction of the head followed by epiphysiodesis; for stable slips, the standard approach is to stabilize the slip by in situ epiphysiodesis without reduction [10].
Various techniques have been described to correct the residual deformity. Some authors recommend performing an intertrochanteric osteotomy (ITO) as a secondary procedure after closure of the growth plate [11, 12]. In cases of severe chronic slips, many authors advice performing a subcapital osteotomy to correct
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