Dataset Information

Acetabular Bone Defect in Total Hip Arthroplasty for Crowe II or III Developmental Dysplasia of the Hip: A Finite Element Study.

ABSTRACT: Background:The purpose of this study was to establish the finite element analysis (FEA) model of acetabular bone defect in Crowe type II or III developmental dysplasia of the hip (DDH), which could evaluate the stability of the acetabular cup with different types of bone defects, different diameters of femoral ceramic heads, and the use of screws and analyze the stress distribution of screws. Methods:The FEA model was based on the CT scan of a female patient without any acetabular bone defect. The model of acetabular bone defect in total hip arthroplasty for Crowe II or III DDH was made by the increasing superolateral bone defect area of the acetabular cup. Point A was located in the most medial part of the acetabular bone defect. A 52?mm PINNACLE cup with POROCOAT Porous coating was implanted, and two screws (the lengths were 25?mm and 40?mm) were implanted to fix the acetabular cup. The stability of the acetabular cup and the von Mises stress of point A and screws were analyzed by a single-legged stance loading applied in 1948?N (normal working). The different diameters of the femoral ceramic head (28?mm, 32?mm, and 36?mm) were also analyzed. Results:The von Mises stress of point A was gradually increased with the increasing uncoverage values. When the uncoverage values exceeded 24.5%, the von Mises stress of point A without screws increased significantly, leading to instability of the cup. Screws could effectively reduce the von Mises stress of point A with uncoverage values of more than 24.5%. However, the peak von Mises stress in the screws with the uncoverage values that exceeded 24.5% was considerably increased. The diameter of the femoral ceramic head had no significant effect on the von Mises stress and the stability of the acetabular cup. Conclusions:We recommend that uncoverage values of less than 24.5% with or without screw is safe for patients with Crowe II or III DDH.

SUBMITTER: Du Y

PROVIDER: S-EPMC7468597 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Acetabular Bone Defect in Total Hip Arthroplasty for Crowe II or III Developmental Dysplasia of the Hip: A Finite Element Study.

Du Yinqiao Y Fu Jun J Sun Jingyang J Zhang Guoqiang G Chen Jiying J Ni Ming M Zhou Yonggang Y

BioMed research international 20200825

<h4>Background</h4>The purpose of this study was to establish the finite element analysis (FEA) model of acetabular bone defect in Crowe type II or III developmental dysplasia of the hip (DDH), which could evaluate the stability of the acetabular cup with different types of bone defects, different diameters of femoral ceramic heads, and the use of screws and analyze the stress distribution of screws.<h4>Methods</h4>The FEA model was based on the CT scan of a female patient without any acetabular ...[more]

PMID: 32908892

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Project description:BackgroundWhen reconstructing a hip with developmental dysplasia and high dislocation, sub-trochanteric shortening osteotomy is typically needed for placing the acetabular component in the appropriate anatomical position. However, the procedure can result in complications such as non-union of the osteotomy. We evaluated the contact area and the coincidence rate between the proximal and distal fragments at different femoral osteotomy levels and lengths. We then determined the optimal location of subtrochanteric femoral shortening transverse osteotomy in patients with unilateral Crowe type IV developmental dysplasia of the hip (DDH). The consistency between the proximal and distal segments was assessed as a possible predictive indicator of the union at the osteotomy site.MethodsWe retrospectively reviewed 57 patients with unilateral Crowe type IV?DDH who underwent X-ray imaging of both hip joints. We labelled the inner and outer diameters of the circular ring as N (mm) and M (mm), respectively. We defined the overlapped area between the proximal and distal ring as contact area S (mm2), and the ratio of contact area to distal ring area as coincidence rate R.ResultsN varied from 9.8-15.2?mm and M varied from 20.7-24?mm, both demonstrated a decreasing trend in the proximal to distal direction. At osteotomy lengths ranging from 0.5-2?cm, there were no differences in S between the different levels of osteotomy in each group. At osteotomy lengths ?2.5?cm, a significant higher coincidence rate was noted from 2?cm below the lesser trochanter to other positions below the level. At osteotomy lengths from 3 to 5.5?cm, a significantly higher coincidence rate was observed from the level of 1.5?cm below the lesser trochanter to other positions below the level.ConclusionsOur findings suggest that femoral shortening transverse osteotomy at the optimal subtrochanteric level can predictably increase the contact area and coincidence rate, which may contribute to the union at the osteotomy site. Considering the stability of the prostheses, it appears appropriate that osteotomy location should be shifted slightly distally.Trial registrationRetrospectively registered.

Project description:BackgroundThis study aimed to accurately evaluate the matching of proximal and distal femoral segments and fitting of the femur-femoral stem in patients with Crowe type IV developmental dysplasia of the hip (DDH) who have undergone subtrochanteric osteotomy at different locations with an implanted Wagner cone stem to improve the rate of the bone union at the osteotomy site.MethodsThree-dimensional femur morphology of 40 patients with Crowe type IV DDH was evaluated at each cross-section to determine the femoral cortical bone area. This study focused on five osteotomy lengths (2.5, 3, 3.5, 4, and 4.5 cm). The overlapped area between the proximal and distal cortical bone segments was defined as the contact area (S, mm2), and the contact area to distal cortical bone area ratio was defined as the coincidence rate (R). Three indicators were used to evaluate the matching and fitting of the osteotomy sites with the implanted Wagner cone stems: (1) higher S and R between the proximal and distal segments; (2) the effective fixation length of the femoral stem at the distal segments being at least 1.5 cm; and (3) osteotomy did not involve the isthmus.ResultsIn all groups, S significantly decreased in the two proximal levels above the 0.5 cm level below the lesser trochanter (LT) compared with those below this level. In comparison, at osteotomy lengths from 2.5 to 4 cm, R significantly decreased in the three proximal levels. The optimal osteotomy levels ranged from 1.5 and 2.5 cm below the LT for an appropriately sized stem.ConclusionsSubtrochanteric osteotomy at the optimal level not only ensures fitting of the femur-femoral stem but also meets the requirements of a higher S and R to ensure adequate reduction and stabilization at the osteotomy site, which may contribute to the bone union. Although the optimal osteotomy level varies with the size of the femoral stem and the length of the subtrochanteric osteotomy, the optimal osteotomy levels for an appropriately sized Wagner cone femoral stem implantation range from 1.5 to 2.5 cm below the LT.

Dataset Information

Acetabular Bone Defect in Total Hip Arthroplasty for Crowe II or III Developmental Dysplasia of the Hip: A Finite Element Study.

Publications

Acetabular Bone Defect in Total Hip Arthroplasty for Crowe II or III Developmental Dysplasia of the Hip: A Finite Element Study.

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