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Three-dimensional femoral morphology in Hartofilakidis type C developmental dysplastic hips and the implications for
Zhaolun Wang1, Hua Li1, Yixin Zhou2
1Department of Orthopaedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, No. 31 Xinjiekou East Street, Xicheng District, Beijing, 100035, People's Republic of China.
Insights
Developmental dysplasia of the hip (DDH) types C1 and C2 show distinct femoral morphologies. These differences impact total hip arthroplasty (THA) by necessitating specific implant choices and surgical techniques for C2 cases.
Area of Science:
- Orthopedic Surgery
- Radiology
- Biomedical Engineering
Background:
- Developmental dysplasia of the hip (DDH) is a condition affecting hip joint formation.
- Hartofilakidis classification categorizes DDH severity.
- Understanding femoral morphology in DDH is crucial for surgical planning.
Purpose of the Study:
- To compare the femoral morphologies of Hartofilakidis types C1 and C2 DDH.
- To evaluate the implications of these morphologies for total hip arthroplasty (THA).
Main Methods:
- Analysis of preoperative CT scans from 81 patients with Hartofilakidis type C DDH undergoing THA.
- 3D reconstruction and measurement of key femoral parameters (neck-shaft angle, neck length, anteversion, etc.).
- Calculation of canal flare indices and ML-to-AP ratio; review of surgical and follow-up records.
Main Results:
- C2 femurs exhibited significantly lower neck-shaft angles, shorter femoral necks, and greater medial inclination compared to C1.
- C2 femurs were narrower with smaller canal flare indices and ML-to-AP ratios.
- C2 hips required thinner stems, more non-sprouted sleeves, and longer shortening osteotomies, with similar clinical outcomes post-THA.
Conclusions:
- Significant morphological differences exist between C1 and C2 proximal femurs in coronal, sagittal, and axial planes.
- C2 femurs present unique challenges in THA, often requiring specialized implants and techniques.
- Despite morphological variations, THA outcomes were comparable between C1 and C2 groups in this study.
Purposes:
The aim of this study was to describe and compare the femoral morphologies of Hartofilakidis types C1 and C2 developmental dysplasia of the hip (DDH), and discuss the potential influence on subsequent total hip arthroplasty (THA).
Methods:
We analyzed preoperative CT data from 81 patients (42 C1 and 39 C2 subtypes) who underwent THA for arthritis secondary to Hartofilakidis type C DDH. The CT data was three-dimensionally reconstructed and measured of following parameters: neck-shaft angle, femoral neck length, anteversion, medial inclination, femoral offset, height of the greater trochanter and femoral head, mediolateral (ML) and anteroposterior (AP) widths of the medullary canal. The canal flare indices and ML-to-AP ratio were further calculated. We also reviewed surgical and follow-up records to compare the different implants utilized and the clinical results between C1 and C2 hips.
Results:
The C2 femurs had a significantly lower neck-shaft angle (119.0° vs. 124.0°), shorter femoral neck (37.0 mm vs. 41.2 mm), larger medial cortical inclination (158.8° vs. 149.1°), and higher position of the greater trochanter. The C2 femurs were narrower and had a smaller canal flare index (2.88 ± 0.50) than C1 femurs (3.64 ± 0.69). The ML-to-AP ratio of the proximal femoral medullary canal was significantly smaller in the C2 group. Accordingly, C2 femurs required thinner stems, more non-sprouted sleeves, and had a higher rate and required a longer length of shortening osteotomies. At an average follow-up of 36.0 months, the C1 and C2 groups had a similar Harris Hip Score (83.5 ± 14.3 vs. 84.2 ± 9.8, P = 0.771) and no stem loosening occurred in either group.
Conclusion:
C1 and C2 proximal femurs have substantial differences in the coronal, sagittal, and axial planes. In the setting of THA, C2 femurs may therefore require thinner stems, more non-sprouted sleeves, and have a higher rate and require a longer length of shortening osteotomies.
