Three‐dimensional mapping of the joint space for the diagnosis of knee osteoarthritis based on high resolution computed tomography: Comparison with radiographic, outerbridge, and meniscal classifications

Abstract

One of the most important characteristic of knee osteoarthritis (OA) is the joint space (JS) width narrowing. Measurements are usually performed on two dimensional (2D) X‐rays. We propose and validate a new method to assess the 3D joint space at the medial knee compartment using high resolution peripheral computed tomography images. A semi‐automated method was developed to obtain a distance 3D map between femur an tibia with the following parameters: volume, minimum, maximum, mean, standard deviation, median, asymmetry, and entropy. We analyzed 71 knee specimens (mean age: 85 years), radiographs were performed for the Kellgren Lawrence (KL) score grading. In a subgroup of 41 specimens, the histopathological Outerbridge and meniscal classifications were performed and then cores were harvested from the tibial plateau in three different positions (posterior, central, and peripheral) and imaged at 10 µm of resolution to measure the cartilage thickness. Minimum, maximum, mean, and median were statistically lower and entropy higher between knee specimens classified as KL = 0 and KL = 3–4. Gr1 and 2 were statistically different from Gr3‐4 for minimum, asymmetry, entropy using the Outerbridge classification and Gr1 was statistically different from Gr3–4 using the meniscal classification. Asymmetry, minimum, mean, median and entropy were significantly correlated with cartilage thickness. Parameters extracted from a 3D map of the medial joint space indicate local variations of JS and are related to local measurements of tibial cartilage thickness, and could be consequently useful to identify early OA. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:2380–2391, 2018.

Contribution of Statistical Iterative Reconstruction Algorithm for Orthopaedic Applications: A Study with a Cone-Beam CT Prototype

“…In a previous study, we used 15 control points for initialization, followed by a snake model to segment joint space in knees. 30 Better results were clearly obtained with the IR reconstruction, with consistent results whatever the intensity, contrary to FDK. Therefore, The DICE index results are convergent with the SSIM results.…”

“…We previously developed a semi-automatic segmentation method of the joint space on CT images. 30 Briefly, the method is applied on the frontal view, and a region of interest corresponding to the medial compartment of the knee is manually selected. For removing noise, a circular averaging filter within the square matrix of 8 size is used.…”

Contribution of Statistical Iterative Reconstruction Algorithm for Orthopaedic Applications: A Study with a Cone-Beam CT Prototype

“…In a previous study, we used 15 control points for initialization, followed by a snake model to segment joint space in knees. 30 Better results were clearly obtained with the IR reconstruction, with consistent results whatever the intensity, contrary to FDK. Therefore, The DICE index results are convergent with the SSIM results.…”

“…We previously developed a semi-automatic segmentation method of the joint space on CT images. 30 Briefly, the method is applied on the frontal view, and a region of interest corresponding to the medial compartment of the knee is manually selected. For removing noise, a circular averaging filter within the square matrix of 8 size is used.…”

High‐Fidelity Measurement‐Based Detection Values and Roles of Three‐Dimensional Joint Space Width in Evaluation of Knee Osteoarthritis

“…The lower threshold (0.2 mm) was used to identify errors likely to affect sensitivity to subtle differences, whereas the higher threshold (0.5 mm) was used to identify errors likely to be clinically consequential. These thresholds were selected to assess whether mesh-induced measurement error remained small relative to clinically relevant change thresholds reported in prior OA studies [2,3,10,12].…”

“…The Osteoarthritis Research Society International-Outcome Measures in Rheumatoid Arthritis Clinical Trials initiative proposes that a 0.5 mm difference in medial JSW measured by X-ray is a general threshold for judging structural loss [2]. The lower the baseline JSW value, the worse the clinical outcome: for every 0.1 mm difference in JSW, the future risk of receiving knee arthroplasty increases by 14% [10]. Even under optimal fluoroscopic guidance, a measurement difference of at least 0.59 mm is required to exceed the measurement error; without fluoroscopic guidance, this threshold rises to 1.29 mm [8].…”

Lateral Knee Osteoarthritis

“…[20,21] Computerized axial tomography has very specific indications in patients with lateral knee osteoarthritis and its use is reserved for evaluating bone anatomy in surgical planning. [22,23] Treatment methods for patients with lateral knee osteoarthritis are similar to those of the rest of the compartments; however patients tolerate nonoperative treatment better than those with medial compartment involvement. [24,25]…”

Contribution of Statistical Iterative Reconstruction Algorithm for Orthopaedic Applications: A Study with a Cone-Beam CT Prototype

“…In a previous study, we used 15 control points for initialization, followed by a snake model to segment joint space in knees. 30 Better results were clearly obtained with the IR reconstruction, with consistent results whatever the intensity, contrary to FDK. Therefore, The DICE index results are convergent with the SSIM results.…”

“…We previously developed a semi-automatic segmentation method of the joint space on CT images. 30 Briefly, the method is applied on the frontal view, and a region of interest corresponding to the medial compartment of the knee is manually selected. For removing noise, a circular averaging filter within the square matrix of 8 size is used.…”

High‐Fidelity Measurement‐Based Detection Values and Roles of Three‐Dimensional Joint Space Width in Evaluation of Knee Osteoarthritis

“…The lower threshold (0.2 mm) was used to identify errors likely to affect sensitivity to subtle differences, whereas the higher threshold (0.5 mm) was used to identify errors likely to be clinically consequential. These thresholds were selected to assess whether mesh-induced measurement error remained small relative to clinically relevant change thresholds reported in prior OA studies [2,3,10,12].…”

“…The Osteoarthritis Research Society International-Outcome Measures in Rheumatoid Arthritis Clinical Trials initiative proposes that a 0.5 mm difference in medial JSW measured by X-ray is a general threshold for judging structural loss [2]. The lower the baseline JSW value, the worse the clinical outcome: for every 0.1 mm difference in JSW, the future risk of receiving knee arthroplasty increases by 14% [10]. Even under optimal fluoroscopic guidance, a measurement difference of at least 0.59 mm is required to exceed the measurement error; without fluoroscopic guidance, this threshold rises to 1.29 mm [8].…”

Lateral Knee Osteoarthritis

“…[20,21] Computerized axial tomography has very specific indications in patients with lateral knee osteoarthritis and its use is reserved for evaluating bone anatomy in surgical planning. [22,23] Treatment methods for patients with lateral knee osteoarthritis are similar to those of the rest of the compartments; however patients tolerate nonoperative treatment better than those with medial compartment involvement. [24,25]…”

Contribution of Statistical Iterative Reconstruction Algorithm for Orthopaedic Applications: A Study with a Cone-Beam CT Prototype

“…In a previous study, we used 15 control points for initialization, followed by a snake model to segment joint space in knees. 30 Better results were clearly obtained with the IR reconstruction, with consistent results whatever the intensity, contrary to FDK. Therefore, The DICE index results are convergent with the SSIM results.…”

“…We previously developed a semi-automatic segmentation method of the joint space on CT images. 30 Briefly, the method is applied on the frontal view, and a region of interest corresponding to the medial compartment of the knee is manually selected. For removing noise, a circular averaging filter within the square matrix of 8 size is used.…”

High‐Fidelity Measurement‐Based Detection Values and Roles of Three‐Dimensional Joint Space Width in Evaluation of Knee Osteoarthritis

“…The lower threshold (0.2 mm) was used to identify errors likely to affect sensitivity to subtle differences, whereas the higher threshold (0.5 mm) was used to identify errors likely to be clinically consequential. These thresholds were selected to assess whether mesh-induced measurement error remained small relative to clinically relevant change thresholds reported in prior OA studies [2,3,10,12].…”

“…The Osteoarthritis Research Society International-Outcome Measures in Rheumatoid Arthritis Clinical Trials initiative proposes that a 0.5 mm difference in medial JSW measured by X-ray is a general threshold for judging structural loss [2]. The lower the baseline JSW value, the worse the clinical outcome: for every 0.1 mm difference in JSW, the future risk of receiving knee arthroplasty increases by 14% [10]. Even under optimal fluoroscopic guidance, a measurement difference of at least 0.59 mm is required to exceed the measurement error; without fluoroscopic guidance, this threshold rises to 1.29 mm [8].…”

Lateral Knee Osteoarthritis

“…[20,21] Computerized axial tomography has very specific indications in patients with lateral knee osteoarthritis and its use is reserved for evaluating bone anatomy in surgical planning. [22,23] Treatment methods for patients with lateral knee osteoarthritis are similar to those of the rest of the compartments; however patients tolerate nonoperative treatment better than those with medial compartment involvement. [24,25]…”