Patterns of Femorotibial Cartilage Loss in Knees With Neutral, Varus, and Valgus Alignment

Paracelsus Medical University, Salzburg, Austria.
Arthritis & Rheumatology (Impact Factor: 7.76). 11/2008; 59(11):1563-70. DOI: 10.1002/art.24208
Source: PubMed

ABSTRACT Malalignment is known to alter medial-to-lateral femorotibial load distribution and to affect osteoarthritis (OA) progression in the mechanically stressed compartment. We investigated the pattern of cartilage loss in neutral, varus, and valgus knees.
Alignment was measured from full-limb radiographs in 174 participants with symptomatic knee OA. Coronal magnetic resonance images were acquired at baseline and a mean +/- SD of 26.6 +/- 5.4 months later. The weight-bearing femorotibial cartilages were segmented from paired images. Cartilage volume, surface area, and thickness were determined in total cartilage plates and defined subregions using proprietary software.
The medial-to-lateral ratio of femorotibial cartilage loss was 1.4:1 in neutral knees (n = 74), 3.7:1 in varus knees (n = 57), and 1:6.0 in valgus knees (n = 43). The relative contribution of cartilage thickness change tended to be greater in knees with mild cartilage loss, whereas the increase of denuded area was greater in knees with accelerated cartilage loss. In both varus and neutral knees, the greatest changes were observed in the same subregions of the medial femorotibial compartment (central and external medial tibia, and central medial femur). In valgus and neutral knees, the subregions with the greatest changes in the lateral femorotibial compartment were also similar (internal and central lateral tibia, external lateral femur).
The medial-to-lateral rate of femorotibial cartilage loss strongly depended on alignment. Subregions of greater-than-average cartilage loss within the stressed compartment were, however, similar in neutral, varus, and valgus knees. This indicates that the medial-to-lateral loading pattern is different, but that the (sub)regional loading pattern may not differ substantially between neutral and malaligned knees.

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Available from: Pottumarthi Vara Prasad, Feb 26, 2014
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    • "To further assess construct validity of the CDI we tested its association with static knee alignment, a well-established risk factor for medial cartilage damage [23,27,32,33]. One reader measured static alignment, hip-knee-ankle (HKA) angle on standing full-limb radiographs that were collected at either the 12- or 24-month OAI visit using a semi-automated program (developed by Jeff Duryea, ICC > 0.99). "
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    ABSTRACT: Background Cartilage morphometry based on magnetic resonance images (MRIs) is an emerging outcome measure for clinical trials among patients with knee osteoarthritis (KOA). However, current methods for cartilage morphometry take many hours per knee and require extensive training on the use of the associated software. In this study we tested the feasibility, reliability, and construct validity of a novel osteoarthritis cartilage damage quantification method (Cartilage Damage Index [CDI]) that utilizes informative locations on knee MRIs. Methods We selected 102 knee MRIs from the Osteoarthritis Initiative that represented a range of KOA structural severity (Kellgren Lawrence [KL] Grade 0 – 4). We tested the intra- and inter-tester reliability of the CDI and compared the CDI scores against different measures of severity (radiographic joint space narrowing [JSN] grade, KL score, joint space width [JSW]) and static knee alignment, both cross-sectionally and longitudinally. Results Determination of the CDI took on average14.4 minutes (s.d. 2.1) per knee pair (baseline and follow-up of one knee). Repeatability was good (intra- and inter-tester reliability: intraclass correlation coefficient >0.86). The mean CDI scores related to all four measures of osteoarthritis severity (JSN grade, KL score, JSW, and knee alignment; all p values < 0.05). Baseline JSN grade and knee alignment also predicted subsequent 24-month longitudinal change in the CDI (p trends <0.05). During 24 months, knees with worsening in JSN or KL grade (i.e. progressors) had greater change in CDI score. Conclusions The CDI is a novel knee cartilage quantification method that is rapid, reliable, and has construct validity for assessment of medial tibiofemoral osteoarthritis structural severity and its progression. It has the potential to addresses the barriers inherent to studies requiring assessment of cartilage damage on large numbers of knees, and as a biomarker for knee osteoarthritis progression.
    BMC Musculoskeletal Disorders 08/2014; 15(1):264. DOI:10.1186/1471-2474-15-264 · 1.72 Impact Factor
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    • "The spatial heterogeneity of cartilage loss in OA patients may provide an explanation why subregional assessment of cartilage does not show a higher sensitivity to change. There is evidence that knee alignment determines the patterns of cartilage loss in the medial versus lateral compartment [Eckstein et al. 2008; Sharma et al. 2008] and that local biomechanical environment may be responsible for certain subregions to progress faster than others in certain subjects [Roemer et al. 2009]. Furthermore, in contrast to weightbearing radiographs, MRI is non-weight-bearing, thus the central regions on knee MRIs may not be anatomical and may not be the weight-bearing regions particularly when there is malalignment. "
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    ABSTRACT: Magnetic resonance imaging (MRI) enables a noninvasive, three-dimensional assessment of the entire joint, simultaneously allowing the direct visualization of articular cartilage. Thus, MRI has become the imaging modality of choice in both clinical and research settings of musculoskeletal diseases, particular for osteoarthritis (OA). Although radiography, the current gold standard for the assessment of OA, has had recent significant technical advances, radiographic methods have significant limitations when used to measure disease progression. MRI allows accurate and reliable assessment of articular cartilage which is sensitive to change, providing the opportunity to better examine and understand preclinical and very subtle early abnormalities in articular cartilage, prior to the onset of radiographic disease. MRI enables quantitative (cartilage volume and thickness) and semiquantitative assessment of articular cartilage morphology, and quantitative assessment of cartilage matrix composition. Cartilage volume and defects have demonstrated adequate validity, accuracy, reliability and sensitivity to change. They are correlated to radiographic changes and clinical outcomes such as pain and joint replacement. Measures of cartilage matrix composition show promise as they seem to relate to cartilage morphology and symptoms. MRI-derived cartilage measurements provide a useful tool for exploring the effect of modifiable factors on articular cartilage prior to clinical disease and identifying the potential preventive strategies. MRI represents a useful approach to monitoring the natural history of OA and evaluating the effect of therapeutic agents. MRI assessment of articular cartilage has tremendous potential for large-scale epidemiological studies of OA progression, and for clinical trials of treatment response to disease-modifying OA drugs.
    Therapeutic advances in musculoskeletal disease 04/2012; 4(2):77-97. DOI:10.1177/1759720X11431005
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    • "Once OA is present because of an individual predisposition [2], deformations occurring in these regions may lead to changes in cartilage composition, to altered cartilage mechanical properties and if persisting to loss in cartilage tissue [42]. The subregional pattern of cartilage deformation observed here was very similar to that observed with regard to the subregional pattern of cartilage (thickness) loss in MR imaging-based longitudinal studies of knee OA [43–46]. This agreement of spatial patterns suggests that the subregions encountering the greatest magnitude of deformation (in OA and healthy knees) are the same as those that also encounter the greatest rates of cartilage loss in knee OA, and that progression of cartilage loss in OA may thus be mechanically driven. "
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    ABSTRACT: To explore and to compare the magnitude and spatial pattern of in vivo femorotibial cartilage deformation in healthy and in osteoarthritic (OA) knees. One knee each in 30 women (age: 55 ± 6 years; BMI: 28 ± 2.4 kg/m(2); 11 healthy and 19 with radiographic femorotibial OA) was examined at 3Tesla using a coronal fat-suppressed gradient echo SPGR sequence. Regional and subregional femorotibial cartilage thickness was determined under unloaded and loaded conditions, with 50% body weight being applied to the knee in 20° knee flexion during imaging. Cartilage became significantly (p < 0.05) thinner during loading in the medial tibia (-2.7%), the weight-bearing medial femur (-4.1%) and in the lateral tibia (-1.8%), but not in the lateral femur (+0.1%). The magnitude of deformation in the medial tibia and femur tended to be greater in osteoarthritic knees than in healthy knees. The subregional pattern of cartilage deformation was similar for the different stages of radiographic OA. Osteoarthritic cartilage tended to display greater deformation upon loading than healthy cartilage, suggesting that knee OA affects the mechanical properties of cartilage. The pattern of in vivo deformation indicated that cartilage loss in OA progression is mechanically driven.
    European Radiology 03/2011; 21(6):1127-35. DOI:10.1007/s00330-011-2057-y · 4.01 Impact Factor
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