Prevalence of Avascular Necrosis Following Surgical Treatments in Unstable Slipped Capital Femoral Epiphysis (SCFE): A Systematic Review and Meta-Analysis

Abstract

The choice of treatment for unstable and severely displaced slipped capital femoral epiphysis (SCFE) is controversial. This meta-analysis was conducted to determine the prevalence of femoral head avascular necrosis (AVN) following various treatments for unstable SCFE. Various databases were searched to identify articles published until 4 February 2022. A random-effects model was used to examine prevalence as well as risk ratios with confidence intervals (CIs) of 95%. Thirty-three articles were analyzed in this study. The pooled prevalences of AVN in pinning in situ, pinning following intentional closed reduction, pinning following unintentional closed reduction, and open reduction via the Parsch method, subcapital osteotomy and the modified Dunn procedure were 18.5%, 23.0%, 27.6%, 9.9%, 18.6% and 19.9%, respectively. The risk of developing AVN in pinning following intentional closed reduction was found to be 1.62 times higher than pinning in situ; however, this result was not significant. The prevalence of AVN in open reduction was lowest when performed via the Parsch method; however, this finding should be interpreted with caution, since the majority of slips so-treated are of mild and moderate types as compared with the subcapital osteotomy and modified Dunn procedures, which are predominantly used to treat severely displaced slips. As the risk ratio between intentional closed reduction and the modified Dunn method showed no significant difference, we believe that the modified Dunn method has the advantage of meticulously preserving periosteal blood flow to the epiphysis, thus minimizing AVN risk. In comparison with intentional closed reduction, the modified Dunn method is used predominantly in cases of severe slips.

Keywords: avascular necrosis; osteonecrosis; unstable slip; unstable slipped capital femoral epiphysis.

Figure 1

PRISMA flow diagram of study selection.

Figure 2

Prevalence (A,B) and risk (C) of developing avascular necrosis following closed pinning and open reduction in patients with unstable slipped capital femoral epiphysis. (A) Closed pinning. (B) Open reduction. (C) Estimated risk ratio in closed pinning versus open reduction.

Figure 2

Prevalence (A,B) and risk (C) of developing avascular necrosis following closed pinning and open reduction in patients with unstable slipped capital femoral epiphysis. (A) Closed pinning. (B) Open reduction. (C) Estimated risk ratio in closed pinning versus open reduction.

Figure 3

Subgroup analyses of the estimated risk ratios. PIS = pinning in situ, CR(I) = pinning following intentional closed reduction, CR(I+UI) = pinning following intentional + unintentional closed reduction, OR = open reduction, SCO = subcapital osteotomy via anterior/anterolateral hip approach. (A) Estimated risk ratio in CR(I) and CR(I+UI) versus PIS. (B) Estimated risk ratio in PIS versus OR (Parsch method). (C) Estimated risk ratio in PIS versus OR (subcapital osteotomy (SCO)). (D) Estimated risk ratio in PIS versus OR (modified Dunn). (E) Estimated risk ratio in CR(I) and CR(I+UI) versus OR (Parsch). (F) Estimated risk ratio in CR(I) and CR(I+UI) versus OR (SCO). (G) Estimated risk ratio in CR(I) versus OR (modified Dunn).

Figure 3

Subgroup analyses of the estimated risk ratios. PIS = pinning in situ, CR(I) = pinning following intentional closed reduction, CR(I+UI) = pinning following intentional + unintentional closed reduction, OR = open reduction, SCO = subcapital osteotomy via anterior/anterolateral hip approach. (A) Estimated risk ratio in CR(I) and CR(I+UI) versus PIS. (B) Estimated risk ratio in PIS versus OR (Parsch method). (C) Estimated risk ratio in PIS versus OR (subcapital osteotomy (SCO)). (D) Estimated risk ratio in PIS versus OR (modified Dunn). (E) Estimated risk ratio in CR(I) and CR(I+UI) versus OR (Parsch). (F) Estimated risk ratio in CR(I) and CR(I+UI) versus OR (SCO). (G) Estimated risk ratio in CR(I) versus OR (modified Dunn).

Figure 4

Funnel plots representing publication bias in relation to the prevalence of avascular necrosis following (A) closed pinning and (B) open reduction in patients with unstable slipped capital femoral epiphysis. (A) Egger’s test p = 0.102. (B) Egger’s test p = 0.882.

Figure 4

Funnel plots representing publication bias in relation to the prevalence of avascular necrosis following (A) closed pinning and (B) open reduction in patients with unstable slipped capital femoral epiphysis. (A) Egger’s test p = 0.102. (B) Egger’s test p = 0.882.

Figure 5

Galbraith plots representing outlier studies, if any, assessing the prevalence of avascular necrosis followed by (A) closed pinning and (B) open reduction in patients with unstable slipped capital femoral epiphysis.