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Updated: Jul 19, 2026
Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Efficacy of MRI in classifying proximal focal femoral deficiency
C Maldjian1, T Y Patel, R M Klein
1New York Medical College, 95 Grasslands Road, Valhalla, NY 10595, USA.
Objective:
To evaluate the efficacy of MRI in classifying PFFD and to compare MRI to radiographic classification of PFFD.
Design:
Radiographic and MRI classification of the cases was performed utilizing the Amstutz classification system.
Patients:
Retrospective evaluation of radiographs and MRI exams in nine hips of eight patients with proximal focal femoral deficiency was performed by two radiologists.
Results:
The cases were classified by radiographs as Amstutz 1: n=3, Amstutz 3: n=3, Amstutz 4: n=1 and Amstutz 5: n=2. The classifications based on MRI were Amstutz 1: n=6, Amstutz 2: n=1, Amstutz 3: n=0, Amstutz 4: n=2 and Amstutz 5: n=0. Three hips demonstrated complete agreement. There were six discordant hips. In two of the discordant cases, follow-up radiographs of 6 months or greater intervals were available and helped to confirm MRI findings. Errors in radiographic evaluation consisted of overestimating the degree of deficiency.
Conclusion:
MRI is more accurate than radiographic evaluation for the classification of PFFD, particularly early on, prior to the ossification of cartilaginous components in the femurs. Since radiographic evaluation tends to overestimate the degree of deficiency, MRI is a more definitive modality for evaluation of PFFD.
Insights
Magnetic Resonance Imaging (MRI) offers superior accuracy in classifying proximal focal femoral deficiency (PFFD) compared to radiographs, especially in early stages. MRI provides a more definitive assessment of PFFD, avoiding overestimation common in radiographic evaluations.
Area of Science:
- Orthopedics
- Medical Imaging
- Pediatric Radiology
Background:
- Proximal focal femoral deficiency (PFFD) is a congenital limb malformation requiring accurate classification for treatment planning.
- Radiographic methods are standard for PFFD assessment but may have limitations in early developmental stages.
- The Amstutz classification system is commonly used for categorizing PFFD severity.
Purpose of the Study:
- To determine the diagnostic efficacy of Magnetic Resonance Imaging (MRI) in classifying proximal focal femoral deficiency (PFFD).
- To compare the accuracy of MRI-based PFFD classification against traditional radiographic assessments.
- To evaluate the utility of the Amstutz classification system across both imaging modalities.
Main Methods:
- Retrospective review of nine hip cases in eight patients diagnosed with PFFD.
- Independent classification of PFFD severity using the Amstutz system by two radiologists for both radiographic and MRI data.
- Comparison of classification results between MRI and radiographic evaluations.
Main Results:
- Radiographic classification yielded Amstutz types 1, 3, 4, and 5.
- MRI classification resulted in Amstutz types 1, 2, and 4, showing a different distribution.
- Significant discordance (6 out of 9 hips) was observed between MRI and radiographic classifications, with radiographs tending to overestimate deficiency severity.
Conclusions:
- MRI demonstrates superior accuracy compared to radiography for classifying PFFD.
- MRI is particularly advantageous in early PFFD assessment before full ossification of femoral components.
- MRI provides a more definitive evaluation of PFFD, mitigating the overestimation issues inherent in radiographic interpretations.
