The characteristics of the whole pelvic morphology in slipped capital femoral epiphysis: A retrospective observational study

Does spinopelvic alignment affect femoral head cartilage and the proximal femoral physis in slipped capital femoral epiphysis? A finite element analysis

BACKGROUND

Slipped capital femoral epiphysis is a prevalent pediatric hip disorder. Recent studies suggest the spine's sagittal profile may influence the proximal femoral growth plate's slippage, an aspect not extensively explored. This study utilizes finite element analysis to investigate how various spinopelvic alignments affect shear stress and growth plate slip.

METHODS

A finite element model was developed from CT scans of a healthy adult male lumbar spine, pelvis, and femurs. The model was subjected to various sagittal alignments through reorientation. Simulations of two-leg stance, one-leg stance, walking heel strike, ascending stairs heel strike, and descending stairs heel strike were conducted. Parameters measured included hip joint contact area, stress, and maximum growth plate Tresca (shear) stress.

FINDINGS

Posterior pelvic tilt cases indicated larger shear stresses compared to the anterior pelvic tilt variants except in two leg stance. Two leg stance resulted in decreases in the posterior tilted pelvi variants hip contact and growth plate Tresca stress compared to anterior tilted pelvi, however a combination of posterior pelvic tilt and high pelvic incidence indicated larger shear stresses on the growth plate. One leg stance and heal strike resulted in higher shear stress on the growth plate in posterior pelvic tilt variants compared to anterior pelvic tilt, with a combination of posterior pelvic tilt and high pelvic incidence resulting in the largest shear.

INTERPRETATION

Our findings suggest that posterior pelvic tilt and high pelvic incidence may lead to increased shear stress at the growth plate. Activities performed in patients with these alignments may predispose to biomechanical loading that shears the growth plate, potentially leading to slip.

Slipped Capital Femoral Epiphysis Managed by Ganz Safe Surgical Dislocation of Hip: A Case Report with 2 Years Follow-up

Introduction

Slipped capital femoral epiphysis (SCFE) is commonly managed by in situ screw fixation. However, higher grades of slips require restoration of normal anatomy of the femoral head without compromising the blood supply.

Case Report

A 16-year-old adolescent male presented with the left hip pain and progressive limping for 4 days with no history of previous trauma. On examination, the patient had severe tenderness and gross restriction of movements. Radiological examination revealed Grade 2 acute on chronic SCFE with unstable slip. Modified Dunn procedure through Ganz surgical hip dislocation facilitated the complete restoration of normal anatomy without avascular necrosis of femoral head changes at 2 years of follow-up.

Conclusion

Ganz safe surgical dislocation of the hip is safe for the femoral head, preserving its blood supply in toto and the modified Dunn procedure facilitated the complete restoration of normal anatomy even in acute on chronic type of SCFE cases.

The Anatomical Position of Graf’s Standard Plane and Its Relationship With Pelvic Morphology: A Computed Tomography-Based Study

Objective

The Graf method is the most widely used ultrasonographic method for evaluating developmental dysplasia of the hip (DDH), and it relies on a set standard plane. However, no previous reports have discussed the detailed anatomical location of the plane. The aim of this study was to evaluate the exact anatomical position of Graf’s standard plane in the pelvis and to ascertain the correlation between this position and pelvic morphology in children without abnormal pelvic morphology.

Methods

We retrospectively assessed the pelvic CT data of 32 children (64 hips) aged three to five years without abnormal pelvic morphology and measured the pelvic winging and acetabular anteversion and coverage. We defined the coronal plane that passed through the center of the bilateral femoral head as plane A. We determined that Graf’s standard plane could be approximated by rotating plane A until the outer wall of the ilium was parallel to the sagittal plane, and we defined this as plane A′. AA′ was defined as the angle from plane A to plane A′ on the sagittal plane. The anterior rotational angle (clockwise, viewing from the right side) was measured as the positive AA′. Moreover, we measured the pelvic rotation, acetabular anteversion, and acetabular coverage and evaluated the correlation between AA′ and these morphological parameters.

Results

The average AA′ was -8.27° and AA′ had a significant correlation with acetabular anteversion (Spearman’s ρ=0.40**, p<0.01).

Conclusions

We found that Graf's standard plane, as determined by the CT scan, tilts slightly posteriorly. This information may be useful in improving the ease of ultrasonographic examination of DDH.