Full length articleDynamic and static knee alignment at baseline predict structural abnormalities on MRI associated with medial compartment knee osteoarthritis after 2 years
Introduction
Osteoarthritis (OA) is a chronic joint disease that typically affects weight-bearing joints [1]. A report on the global burden of disease indicated knee OA as one of the leading causes of disability [2]. The number of knee replacements is small compared to the number of subjects with knee OA [3], [4]. Therefore, as suggested by Cooper et al., preventing progression to severe joint damage may offer a more effective public health strategy than attempting to prevent disease incidence [3]. Developing strategies to prevent (progression of) knee OA requires a thorough understanding of the factors associated with disease incidence and progression. Several risk factors have been reported to be associated with the incidence of knee OA [3], [5], but the number of studies in which risk factors and incidence of knee OA have been investigated longitudinally, is relatively small.
Knee OA is characterized by symptoms such as pain and functional decline along with structural changes detected on radiography or on MRI such as Bone Marrow Lesions (BMLs), Cartilage Lesions (CL), and Meniscal Injuries (MI) [4]. Lesions of bone marrow have been proposed as structural indices for progression of knee OA [6]. Especially in the early stages of the disease, these structural changes can be better identified on MRI [7].
The role of mechanical factors, such as knee joint static (mal)alignment, in progression of knee OA has been well-established [8], [9], [10]. In a study by Hunter et al., it was concluded that the location of BMLs and change in BMLs were mediated by static (mal)alignment [6]. On the other hand, evidence exists that dynamic knee alignment as measured based on the peak knee adduction angle during walking is a stronger predictor of the knee adduction moment (KAM) (and thus indirect loading) than static radiographic (mal)alignment [11]. Frontal plane dynamic alignment, and more specifically varus thrust, is defined as an abrupt increase of the knee varus alignment during weight-bearing in gait, and it is one of the newly proposed clinical indices for knee OA [12], [13], [14]. However, the relation between dynamic knee alignment on one hand, and clinical and structural progression of knee OA on the other, is insufficiently understood.
There is only one single longitudinal study on the association of baseline dynamic alignment, assessed as presence of varus thrust by visual observation, and radiographic progression of knee OA [12]. In this study, the presence of varus thrust at baseline was associated with a 4-fold increased likelihood of progression of medial knee OA over the next 18 months, as measured with the Kellgren and Lawrence scale [12].
In a recent cross-sectional study, Lo et al. compared two groups of subjects with knee osteoarthritis with and without varus thrust as detected by visual inspection, and reported the association of pain with varus thrust to be stronger compared to its relation with static varus alignment [15]. Varus thrust was shown to be associated with KAM [12], [14], which itself is related with a higher prevalence of BMLs in the medial compartment [17]. Medial compartment BMLs in turn have been related to pain [18], [19], [20], [21]. But the relationship between the presence and magnitude of varus thrust with BMLs as well as other structural abnormalities associated with medial knee OA has not yet been investigated. Increased varus thrust can be observed early in the disease process, before signs of an increase in KAM [14].
Therefore, the aim of the present study was to assess both cross-sectionally and longitudinally, the relationship between frontal plane static and dynamic alignment with structural and clinical characteristics of OA in a group of individuals with early and established symptomatic medial knee OA. We hypothesized that higher values of baseline varus thrust magnitude during gait would be associated with structural and clinical abnormalities at the time of entry, as well as with the changes over 2 years.
Section snippets
Materials and methods
Forty-seven patients with medial knee OA participated in this study. The study was approved by the ethical committee for Biomedical Sciences of the KU Leuven in Belgium prior to testing and was conducted in agreement with the principles of the Declaration of Helsinki. All participants were informed about the study procedure and signed informed consent forms.
Participants were recruited during their visit to the University Hospital Leuven. The inclusion criteria for the early OA group were:
Results
Forty-seven women with a mean BMI of 27.17 (SD = 0.7) kg/m2 and mean age of 68 (SD = 0.9) years were included in the analysis. Subjects’ characteristics are presented in Table 1.
Discussion
To the best of our knowledge, this is the first study to assess the associations between the magnitude of varus thrust and static alignment, both, with structural features associated with medial knee OA detected on MRI both cross-sectionally and longitudinally. The main findings of the present study were that both static and dynamic alignment in the frontal plane were significantly associated with OA related tibiofemoral joint structural abnormalities detected on MRI, at the time of entry. Only
Conclusion
The present study showed that both static and dynamic alignment in the frontal plane were significantly associated with OA related tibiofemoral joint structural abnormalities detected on MRI. But, only the dynamic measure magnitude of varus thrust at baseline was predictive of the changes in the presence of meniscal maceration over two years. In previous studies of our group, we reported that the magnitude of varus thrust was already significantly higher in a group of women with early knee OA,
Competing interest statement
The authors declare that they have no conflicts of interest.
Author contributions
AM, IB, FL, and SV contributed to the conception and design of this study. AM, IB and FL contributed to the collection of the data. AM contributed to the analysis of the data with expertise of JvD, JB, and GF. AM, IB, JvD, SB, FL, GF and SV contributed to the interpretation of the data. Article drafts were written by AM and SV and critically revised by all authors. The final version of the article was approved by all authors. AM takes responsibility for the integrity of the work as a whole
Funding source
This study was not financially supported by any study sponsor.
Acknowledgements
This research was funded by the European Commission through MOVE-AGE, an Erasmus Mundus Joint Doctorate programme (2011–2015) and by grants of the FWRO (Belgian Fund for Scientific Rheumatology Research2013-J1820590-101645 and 2012-820590-100367). Sjoerd M. Bruijn was supported by a grant from the Netherlands Organization for Scientific Research (NWO #451-12-041). The authors acknowledge S. Verweijen and C. Smolders for their assistance in performing the clinical measurements, W. van Hoef for
References (37)
The course of osteoarthritis and factors that affect it
Rheum. Dis. Clin. North Am.
(1993)- et al.
Varus thrust in women with early medial knee osteoarthritis and its relation with the external knee adduction moment
Clin. Biomech.
(2016) - et al.
The relationship between specific tissue lesions and pain severity in persons with knee osteoarthritis
Osteoarthritis Cartilage
(2006) - et al.
Bone marrow lesions and joint effusion are strongly and independently associated with weight-bearing pain in knee osteoarthritis: data from the osteoarthritis initiative
Osteoarthritis Cartilage
(2009) - et al.
A simple method for determination of gait events
J. Biomech.
(2002) A FORTRAN package for generalized, cross-validatory spline smoothing and differentiation
Adv. Eng. Softw. (1978)
(1986)- et al.
A quantitative assessment of varus thrust in patients with medial knee osteoarthritis
Knee
(2012) Dynamics of knee malalignment
Orthop. Clin. North Am.
(1994)The mechanics of the knee joint in relation to normal walking
J. Biomech.
(1970)- et al.
The global burden of hip and knee osteoarthritis: estimates from the global burden of disease 2010 study
Ann. Rheum. Dis.
(2014)
Risk factors for the incidence and progression of radiographic knee osteoarthritis
Arthritis Rheum.
The incidence and natural history of knee osteoarthritis in the elderly, the framingham osteoarthritis study
Arthritis Rheum.
Epidemiology of osteoarthritis: prevalence, risk factors and functional impact
Aging Clin. Exp. Res.
Increase in bone marrow lesions associated with cartilage loss: a longitudinal magnetic resonance imaging study of knee osteoarthritis
Arthritis Rheum.
Definition and classification of early osteoarthritis of the knee
Knee Surg. Sports Traumatol. Arthrosc.
The role of knee alignment in disease progression and functional decline in knee osteoarthritis
JAMA
Association between valgus and varus alignment and the development and progression of radiographic osteoarthritis of the knee
Arthritis Rheum.
Does knee malalignment increase the risk of development and progression of knee osteoarthritis? A systematic review
Arthritis Care Res.
Cited by (12)
Knee adduction moment is correlated with the increase in medial meniscus extrusion by dynamic ultrasound in knee osteoarthritis
2022, KneeCitation Excerpt :Meanwhile, progressive knee OA has been shown to be correlated with abnormal mechanical stress such as knee adduction moment and lateral thrust [14–17]. Further, biomechanical stress, according to abnormal gait motion, showed a correlation with the pathological meniscus [9,18–20]. Motion analysis, which detects abnormal gait motion, may then help provide a deeper understanding of the mechanism of MME increase with underlying biomechanical stress.
Are biomechanics during gait associated with the structural disease onset and progression of lower limb osteoarthritis? A systematic review and meta-analysis
2022, Osteoarthritis and CartilageCitation Excerpt :Biomechanical metrics were clearly defined, and structural imaging outcomes used reliable scoring systems with blinded assessors. Seven studies13,37,38,44–46,48 only reported participants with follow-up data and thus attrition was not possible to determine. Table III provides a summary of confirmed associations between baseline biomechanics and OA onset or progression risk.
Are there different gait profiles in patients with advanced knee osteoarthritis? A machine learning approach
2021, Clinical BiomechanicsCitation Excerpt :According to our results, the varus ‘thrust’, represented by an increased knee ROM in the coronal plane, is a more important feature than peak joint angles. The influence of varus ‘thrust’ on knee kinematics is in agreement with previous evidence suggesting this variable as a risk factor for knee pain intensity and OA progression (Iijima et al., 2015; Sharma et al., 2017) as well as structural changes detected using MRI (Mahmoudian et al., 2017; Wink et al., 2017). The lack of significance of the coronal peak knee angles may result from a compensatory kinematic, especially because we opted for assessing the subjects walking at their individual maximal speed.
Increase in medial meniscal extrusion in the weight-bearing position observed on ultrasonography correlates with lateral thrust in early-stage knee osteoarthritis
2020, Journal of Orthopaedic ScienceCitation Excerpt :Severe knee OA usually affects physical function and patients' activities of daily living [1]. Knee OA progression is believed to be associated with increasing mechanical stress due to pathological structural changes in joint compartments [2–4]. Knee lateral thrust is an abnormal lateral knee motion frequently observed in patients with OA.
Toward classification criteria for early osteoarthritis of the knee
2018, Seminars in Arthritis and RheumatismRelationship Between Knee Biomechanics and Pain in People With Knee Osteoarthritis: A Systematic Review and Meta-Analysis
2023, Arthritis Care and Research