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Updated: May 29, 2025
Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty
Published on: February 27, 2018
Pathomorphological features of the proximal femur in crowe IV hips and their implication on stem selection during
Kaveh Gharanizadeh1, Elham Mohammadyahya1, Mohammad Reza Bahaeddini1
1Bone and Joint Reconstruction Research Center, Department of Orthopedics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
Insights
For high-riding developmental dysplasia of the hip (DDH), this study found significant femoral anatomical differences in Crowe type IV patients. These findings guide optimal wedge stem placement for better surgical outcomes.
Area of Science:
- Orthopedic surgery
- Biomedical engineering
- Radiology
Background:
- Femoral shortening in high-riding developmental dysplasia of the hip (DDH) lacks clear stem selection guidelines.
- Understanding proximal femur morphology is crucial for successful surgical intervention in DDH.
Purpose of the Study:
- To compare proximal femur anatomy between Crowe type IV DDH and normal hips using EOS™ imaging.
- To define anatomical landmarks for optimal wedge femoral stem placement in high-riding DDH.
Main Methods:
- EOS™ imaging analysis of 40 Crowe type IV DDH hips and 40 normal hips.
- Measurement of key distances (GT-VR, VR-LT, GT-LT) and Canal Flare Index (CFI).
- Evaluation of anatomical proportions relative to femoral length.
Main Results:
- Crowe IV DDH hips showed a shorter greater trochanter to vastus ridge (GT-VR) distance and a more distal lesser trochanter (LT).
- The LT base width index was larger, and CFI at the LT level was smaller in dysplastic hips.
- CFI values became similar when a cut was made 1.5 cm above the LT.
Conclusions:
- Crowe IV DDH hips exhibit distinct proximal femur morphology, including shorter GT height and distally positioned LT.
- A narrower canal width at the upper LT border and smaller CFI necessitate adjustments for wedge stem fitting.
- Optimal wedge stem implantation in Crowe IV DDH requires a higher neck cut level.
Background:
The best stem type and location for femoral shortening in high-riding developmental dysplasia of the hip (DDH) in not clear. We evaluated the morphology of the proximal femur on EOS™ images, focusing on the anatomical landmarks and measurements relevant to the stem selection in high-riding DDH. Our goal is to identify and define the differences in the anatomy of the proximal femur between patients with Crowe type IV DDH and normal individuals, in order to determine the appropriate neck cut location in these patients to increase the chances of successfully using a wedge femoral stem.
Methods:
EOS™ images of 40 hips with Crowe type-IV DDH and 40 normal hips were included. The distances between the tip of the greater trochanter and vastus ridge (GT-VR), vastus ridge and proximal border of lesser trochanter (VR-LT), greater- and lesser trochanters (GT-LT), base width of the LT, and the proportion of these distances to the femoral length were evaluated. Canal Flare Index (CFI) was also measured, at two different levels.
Results:
The mean GT-LT index was not different between the two groups (p = 0.46). The GT-VR index was smaller in the case group (p < 0.001), while the VR-LT index was greater (p < 0.001). The LT base width index was larger in the case group (P < 0.001). CFI was smaller at the LT level in dysplastic hips (P < 0.001), but the values were similar with a cut 1.5 cm above the LT (P = 0.67).
Conclusion:
In Crowe IV hips, the GT height is shorter and the LT is located far more distally along the femoral metaphysis, resulting in a narrower canal width at the upper border of the lesser trochanter. Also, the CFI at the LT level is smaller, and to fit a wedge stem, the neck cut should be made at a higher level.
