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. 2022 Sep;14(3):370-376.
doi: 10.4055/cios21050. Epub 2022 Feb 7.

Comparison of Lower-Limb Alignment in Patients with Advanced Knee Osteoarthritis: EOS Biplanar Stereoradiography versus Conventional Scanography

Hyeong-Uk Choi  1 , Du-Han Kim  1 , Si-Wook Lee  1 , Byung-Chan Choi  1 , Ki-Cheor Bae  1
Affiliations

Comparison of Lower-Limb Alignment in Patients with Advanced Knee Osteoarthritis: EOS Biplanar Stereoradiography versus Conventional Scanography

Hyeong-Uk Choi et al. Clin Orthop Surg. 2022 Sep.

Abstract

Background: Accurate measurement of the lower limb alignment is one of the most crucial factors in advanced knee osteoarthritis patients scheduled for surgery. Recently, EOS biplanar stereoradiography with three-dimensional reconstruction was developed. The purpose of this study was to compare radiographic parameters between conventional scanography and EOS in patients with advanced knee osteoarthritis who need surgical treatment.

Methods: A total of 52 consecutive patients (104 knees) with bilateral knee osteoarthritis of advanced stage (Kellgren-Lawrence [KL] grade 3 or 4) were retrospectively reviewed. We measured the hip-knee-ankle angle (HKA) on conventional scanograms. In EOS, we measured HKA, hip-knee-shaft angle, mechanical lateral distal femoral angle, and mechanical medial proximal tibial angle. To evaluate sagittal and axial plane alignment, knee flexion angle (KFA), and knee joint rotation (KJR) were also measured.

Results: Ninety knees were KL grade 4, and 14 knees were grade 3. The average HKA was 10.14° ± 6.16° on conventional scanograms and 11.26° ± 6.21° in EOS. HKA was greater in EOS than on conventional scanograms, and the difference (1.12°; range, -1.07° to 3.22°) was statistically significant (p < 0.001). Significant correlations were observed on the difference in HKA and mechanical medial proximal tibial angle (r = -0.198, p = 0.044), KFA (r = 0.193, p = 0.049), and KJR (r = 0.290, p = 0.003). In multivariable linear regression analysis, the difference in HKA had significant relationship with KFA (β = 0.286, p = 0.003) and KJR (β = 0.363, p < 0.001).

Conclusions: HKA measured on conventional scanograms and in EOS differed significantly and the difference had a significant correlations with KFA, KJR, and medial proximal tibial angle. Surgeons can consider these results before orthopedic surgery in patients who have advanced knee osteoarthritis.

Keywords: Alignment; Biplanar steroradiography; Knee osteoarthritis; Scanoram; Total knee arthroplasty.

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Conflict of interest statement

CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported.

Figures

Fig. 1
Fig. 1. Flow diagram of patient selection process. K-L: Kellgren-Lawrence.
Fig. 2
Fig. 2. Radiographic imaging of the hip-knee-ankle angle on conventional scanograms (A) and in EOS (B). (B) The reference points were set simultaneously in both the coronal and sagittal planes.
Fig. 3
Fig. 3. Radiographic imaging of the hip-knee-shaft angle (A), mechanical lateral distal femoral angle (B), and knee flexion angle (C) in EOS.
Fig. 4
Fig. 4. Knee joint rotation was defined as the degree of deviation of the patellar center inward or outward relative to the midpoint of the line connecting both femoral epicondyles (A / B × 100, %). ER: external rotation, IR: internal rotation.
See this image and copyright information in PMC

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