OTSR - 2026-05-04 - Journal Article
Dual-Energy CT Assessment of Distal Femur Bone quality for Preventing Early Failure in Cementless Total Knee Arthroplasty.
Sohn S, Kwak DS, Lee SW, Cho N, Lee SH, Jun Koh I
Topics
Key Takeaway
Preoperative DECT-derived coronal HU of the distal femur correlates with measured bone strength (r=0.67) and identifies cementless TKA candidates with AUC=0.82 at a cutoff of 72 HU.
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Summary
This prospective study asked whether preoperative DECT-derived HU of the distal femur correlates with actual periarticular bone strength and can identify suitable cementless TKA candidates. In 190 knees undergoing primary PS-TKA, coronal-plane DECT HU was compared against intraoperative indentation testing of resected bone fragments; linear regression showed coronal HU independently predicted bone strength (β=0.62, R²=0.45). ROC analysis yielded AUC=0.82 with an optimal cutoff of 72 HU (sensitivity 73%, specificity 74%) for identifying cementless TKA candidacy.
Key Limitation
The 72 HU cutoff is validated only against an indentation test surrogate with no postoperative implant survival or migration data, limiting direct translation to clinical failure prevention.
Original Abstract
BACKGROUND
With the increasing utilization of newer-generation cementless total knee arthroplasty (TKA), the preoperative prediction of bone quality has emerged as a significant concern. Recognizing such limitations of central bone mineral density, attention has turned to Hounsfield units (HU), a measure of the standardized linear attenuation coefficient in computed tomography (CT) imaging, known for its ability to estimate bone marrow density specifically around the knee joint. Consequently, this study aims to investigate the correlation between preoperative dual-energy CT (DECT) HU measurements of the distal femur and the actual bone strength. We hypothesized that DECT-derived HU would (1) significantly correlate with biomechanical bone strength and (2) serve as a reliable tool for identifying suitable candidates for cementless TKA.
MATERIALS AND METHODS
In this prospective study, 190 knees that underwent primary posterior stabilized TKA between May 2022 and May 2023 were included. HU of the distal femur was assessed using DECT scan, which utilizes material decomposition to differentiate bone from soft tissue or bone marrow, providing more accurate bone quality assessment than conventional CT, and the actual bone strength of the corresponding bone fragment was measured using an indentation test that serves as a validated surrogate for traditional compression testing. The association between HU and actual bone strength was evaluated using correlation and linear regression analyses. To further assess its diagnostic utility in identifying candidates for cementless TKA, receiver operating characteristic (ROC) curve analysis with calculation of the area under the curve (AUC) was performed to determine both accuracy and the optimal cutoff value.
RESULTS
The DECT HU value in coronal plane showed significant correlations with bone strength measured by indentation testing (r = 0.67, p < 0.01). In linear regression analysis, coronal HU was independently predictive of bone strength (β = 0.62, R² = 0.45, p < 0.01). Furthermore, coronal HU showed good discriminative ability for identifying candidates suitable for cementless TKA (AUC = 0.82, 95% CI 0.766-0.880), with an optimal cutoff of 72 HU yielding sensitivity of approximately 73% and specificity of 74%.
CONCLUSIONS
This study demonstrates that DECT HU is a promising marker for periarticular bone quality, given its strong correlation with distal femoral bone strength and excellent performance in predicting suitability for cementless TKA. However, considering our simplified model, ethnic diversity, and CT scanner variability, these factors should be taken into account before using this threshold as a definitive clinical guide.
LEVEL OF EVIDENCE
II; Prospective diagnostic study.