Three-dimensional femoral morphology in Hartofilakidis type C developmental dysplastic hips and the implications for total hip arthroplasty

Abstract

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.

Three-dimensional morphological study of the proximal femur in Crowe type IV developmental dysplasia of the hip

“…Regarding the femoral neck anteversion, dysplastic femurs had a significantly larger anteversion than the normal femurs. Without the restriction of false acetabulum, the IVa femurs had a notably larger anteversion than IVb femurs, which was different from the comparable results previously [ 27 ]. Compared with the normal femur, both IVa and IVb femurs had smaller head height and IVb femurs had larger greater trochanter height, resulting in larger GT–FH height discrepancy in both DDH groups.…”

“…However, we found neck-shaft angle in the Crowe IVa group was significantly smaller than that of IVb and normal group, whereas no difference was found between IVb and normal groups. Our results were consistent with the conclusion of Liu [ 4 ] and Wang et al [ 27 ], but Du reported that the angle in IVb was larger than the contralateral normal femur [ 10 ]. The medial offset in both DDH groups was smaller than the normal group and no difference was found between DDH groups, which was consistent with results of Du [ 10 ] and Noble et al [ 15 ].…”

“…Further, the index of IVa femur was smaller than IVb only in the ML dimension but comparable in D +20 /Di. Similarly, Wang et al [ 27 ] also reported that femurs without false acetabulum had a lower CFI in the ML dimension but not the AP dimension. Under the stress of false acetabulum, medullary deformity of IVb femur mainly occurred in the diaphyseal region.…”

“…Du et al [ 10 ] also reported similar results that there was no significant dimensional difference at the level of isthmus. However, Wang et al [ 27 ] demonstrated that the dimensional widths of femurs without false acetabulum were narrower in all the sections. In normal femurs, the ML width of proximal femoral canal is always longer than the AP width [ 17 ].…”

Innovative Design Methodology for Patient-Specific Short Femoral Stems

“…To measure the neck-shaft angle, modifications of the techniques described by Wang et al [26] and Zhang et al [27] were used. Previously, the femoral head was simulated as a sphere; thus, its centers are coincident.…”