3D patellar shape is associated with radiological and clinical signs of patellofemoral osteoarthritis.

OBJECTIVE: To examine the association between 3D patellar shape and 1) isolated magnetic resonance imaging (MRI)-based patellofemoral osteoarthritis (PFOA), 2) the morphological features of PFOA, and 3) the clinical symptoms of PFOA. DESIGN: MRI data from 66 women with isolated MRI-based PFOA and 66 age- and BMI-matched healthy women were selected from a cohort study. The patellae were manually segmented from MRI scans and used to create a 3D statistical shape model (SSM) of the patella. Structural abnormalities were semi-standardized scored on MRI using MRI osteoarthritis knee score (MOAKS). Regression analyses were applied to determine the associations between the shape parameters retrieved from the SSM, group status, clinical symptoms, and structural abnormalities. RESULTS: Four shape variants showed a statistically significant (<0.05) association with the group status. The mode responsible for most of the shape variations showed participants with PFOA possess a relatively thicker dorsal bump on the articular part of the patella, compared to patellae of control participants. Three of these variants showed an association with the presence of osteophytes and cartilage loss on the patella. Multiple associations were found between patellar shape and the clinical symptoms of PFOA. CONCLUSIONS: Patellar shape is associated with the prevalence of MRI-based PFOA in women. Some shape variants were also associated with clinical symptoms. Interestingly, one particular shape variant associated with the presence of MRI-based PFOA was earlier shown to be associated with structural abnormalities associated with OA in a population aged under 40. This may suggest that patellar shape may be an early detectable risk factor for PFOA.

Metabolic syndrome and the progression of knee osteoarthritis on MRI.

OBJECTIVE: Metabolic osteoarthritis (OA) is one of the proposed clinical phenotypes defined by the existence of metabolic syndrome (MetS). This study aimed to (1) investigate whether MetS and its components are associated with progression of knee OA magnetic resonance imaging (MRI) features, and (2) to evaluate the interaction of MetS with menopause and progression of MRI features. METHOD: 682 women from the Rotterdam Study who participated in a sub-study with knee MRI data available and 5-year follow-up were included. Tibiofemoral (TF) and patellofemoral (PF) OA features were assessed with the MRI Osteoarthritis Knee Score. MetS was quantified by the MetS severity Z-score. Generalized estimating equations were used to evaluate associations between MetS and menopausal transition and progression of MRI features. RESULTS: MetS severity at baseline was associated with progression of osteophytes in all compartments, bone marrow lesions (BMLs) in the PF compartment, and cartilage defects in the medial TF compartment. Waist circumference was associated with progression of osteophytes in all compartments and cartilage defects in the medial TF compartment. High-density lipoprotein (HDL)-cholesterol levels were associated with progression of osteophytes in the medial and lateral TF compartment and glucose levels with osteophytes in the PF and medial TF compartment. No interactions were found between MetS with menopausal transition and MRI features. CONCLUSION: Women with higher MetS severity at baseline showed progression of osteophytes, BMLs, and cartilage defects, indicating more structural knee OA progression after 5 years. Further studies are required to understand whether targeting MetS components may prevent the progression of structural knee OA in women.

Changes to consultations and diagnosis of osteoarthritis in primary care during the COVID-19 pandemic.

OBJECTIVE: General practitioners (GP) are often the first medical professionals to treat musculoskeletal complaints. Yet the impact of COVID-19 on primary care utilisation for musculoskeletal complaints is largely unknown. This study quantifies the impact of the pandemic on primary care utilisation for musculoskeletal complaints and specifically osteoarthritis (OA) in the Netherlands. DESIGN: We extracted data on GP consultations in 2015-2020 from 118,756 patients over 45 years of age and estimated reductions in consultations in 2020 as compared to 5-year average. Outcomes were GP consultations for: any musculoskeletal complaints, knee and hip OA, knee and hip complaints, and newly diagnosed knee and hip OA/complaints. RESULTS: The relative reductions in consultations ranged from 46.7% (95% confidence intervals (CI): 43.9-49.3%) (all musculoskeletal consultations) to 61.6% (95% CI: 44.7-73.3%) (hip complaints) at the peak of the first wave, and from 9.3% (95% CI: 5.7-12.7%) (all musculoskeletal consultations) to 26.6% (95% CI: 11.5-39.1%) (knee OA) at the peak of the second wave. The reductions for new diagnoses were 87.0% (95% CI: 71.5-94.1%) for knee OA/complaints, and 70.5% (95% CI: 37.7-86.0%) for hip OA/complaints at the peak of the first wave, and not statistically significant at the peak of the second wave. CONCLUSION: We observed 47% reduction in GP consultations for musculoskeletal disorders during the first wave and 9% during the second wave. For hip and knee OA/complaints, the reductions were over 50% during the first, and 10% during the second wave. This disruption may lead to accumulation of patients with severe OA symptoms and more requests for arthroplasty surgery.

Skin autofluorescence, a non-invasive biomarker of advanced glycation end products, and its relation to radiographic and MRI based osteoarthritis.

OBJECTIVES: Accumulation of advanced glycation end products (AGEs) in articular cartilage during aging has been proposed as a mechanism involved in the development of osteoarthritis (OA). Therefore, we investigated a cross-sectional relationship between skin AGEs, a biomarker for systemic AGEs accumulation, and OA. METHODS: Skin AGEs were estimated with the AGE Reader™ as skin autofluorescence (SAF). Knee and hip X-rays were scored according to Kellgren and Lawrence (KL) system. KL-sum score of all four joints was calculated per participant to assess severity of overall radiographic OA (ROA) including or excluding those with prosthesis. Knee MRI of tibiofemoral joint (TFMRI) was assessed for cartilage loss. Sex-stratified regression models were performed after testing interaction with SAF. RESULTS: 2,153 participants were included for this cross-sectional analysis. In women (n = 1,206) for one unit increase in SAF, the KL-sum score increased by 1.15 (95% confidence interval = 1.00-1.33) but excluding women with prosthesis, there was no KL-sum score increase [0.96 (0.83-1.11)]. SAF was associated with higher prevalence of prosthesis [Odds ratio, OR = 1.67 (1.10-2.54)] but not with ROA [OR = 0.83 (0.61-1.14)] when compared to women with no ROA. In men (n = 947), there was inconclusive association between SAF and KL sum score or prosthesis. For TFMRI (n = 103 women), SAF was associated with higher prevalence of cartilage loss, full-thickness [OR = 5.44 (1.27-23.38)] and partial-thickness [OR = 1.45 (0.38-5.54)], when compared to participants with no cartilage loss. CONCLUSION: Higher SAF in women was associated with higher prosthesis prevalence and a trend towards higher cartilage loss on MRI. Our data presents inconclusive results between SAF and ROA in both sexes.

Estimating incidence and prevalence of hip osteoarthritis using electronic health records: a population-based cohort study.

OBJECTIVE: To determine the incidence and prevalence of hip osteoarthritis (OA) in electronic health records (EHRs) of Dutch general practices by using narrative and codified data. METHOD: A retrospective cohort study was conducted using the Integrated Primary Care Information database. An algorithm was developed to identify patients with narratively diagnosed hip OA in addition to patients with codified hip OA. Incidence and prevalence estimates among people aged ≥30 were assessed from 2008 to 2019. The association of comorbidities with codified hip OA diagnosis was analysed using multivariable logistic regression. RESULTS: Using the hip OA narrative data algorithm (positive predicted value = 72%) in addition to codified hip OA showed a prevalence of 1.76-1.95 times higher and increased from 4.03% in 2008 to 7.34% in 2019. The incidence was 1.83-2.41 times higher and increased from 6.83 to 7.78 per 1000 person-years from 2008 to 2019. Among codified hip OA patients, 39.4% had a previous record of narratively diagnosed hip OA, on average approximately 1.93 years earlier. Hip OA patients with a previous record of spinal OA, knee OA, hypertension, and hyperlipidaemia were more likely to be recorded with a hip OA code. CONCLUSION: This study using Dutch EHRs showed that epidemiological estimates of hip OA are likely to be an underestimation. Using our algorithm, narrative data can be added to codified data for more realistic epidemiological estimates based on routine healthcare data. However, developing a valid algorithm remains a challenge, possibly due to the diagnostic complexity of hip pain in general practice.

Associations between biomarkers of matrix metabolism and inflammation with pain and fatigue in participants suspected of early hip and or knee osteoarthritis: data from the CHECK study.

OBJECTIVES: To assess the associations of biomarkers in serum [highsensitivity C-reactive protein (hs-CRP), serum cartilage oligomeric protein (sCOMP), serum propeptide of type I procollagen (sPINP) and serum osteocalcin (sOC)] and urine [urinary type II collagen telopeptide (uCTX-2)] with the extent and progression of nocturnal pain, pain while walking, and fatigue in participants with hip and/or knee pain suspected to be early stage osteoarthritis (OA). METHODS: hs-CRP, uCTX-2, sCOMP, sPINP and sOC were measured at baseline in 1,002 participants of the Cohort Hip and Cohort Knee (CHECK). Nocturnal pain, pain while walking and fatigue were assessed by self-reported questionnaires at baseline and 2-year follow-up. Associations between these biomarkers and symptoms were examined using logistic and linear regression analyses. RESULTS: hs-CRP was significantly associated with mild nocturnal pain (OR 1.18 95% CI 1.01-1.37), with mild and moderate pain while walking (OR 1.17 95% CI 1.01-1.35 and OR 1.56 95% CI 1.29-1.90, respectively) and with progression of nocturnal pain (OR 1.25 95% CI 1.07-1.46). uCTX-2 was associated with mild nocturnal pain (OR 1.40 95% CI 1.05-1.85) and with mild and severe-extreme pain while walking (OR 1.35 95% CI 1.04-1.75 and OR 2.55 95% CI 1.03-6.34, respectively). sPINP was associated with severe-extreme nocturnal pain (OR 0.45 95% CI 0.25-0.82). No significant associations were found for sCOMP and sOC, nor for any of the biomarkers and fatigue. CONCLUSION: This study of biomarkers in a large cohort of participants with hip and/or knee pain suspected to reflect early stage hip and/or knee OA suggests that inflammation and cartilage matrix degeneration play a role in pain, but not in fatigue.

The association of clinical and structural knee osteoarthritis with physical activity in the middle-aged population: the NEO study.

OBJECTIVE: To investigate if knee osteoarthritis (OA) is associated with lower physical activity in the general middle-aged Dutch population, and if physical activity is associated with patient-reported outcomes in knee OA. DESIGN: Clinical knee OA was defined in the Netherlands Epidemiology of Obesity population using the ACR criteria, and structural knee OA on MRI. We assessed knee pain and function with the Knee Injury and Osteoarthritis Score (KOOS), health-related quality of life (HRQoL) with the Short Form-36, and physical activity (in Metabolic Equivalent of Task (MET) hours) with the Short Questionnaire to Assess Health-enhancing physical activity. We analysed the associations of knee OA with physical activity, and of physical activity with knee pain, function, and HRQoL in knee OA with linear regression adjusted for potential confounders. RESULTS: Clinical knee OA was present in 14% of 6,212 participants, (mean age 56 years, mean BMI 27 kg/m2, 55% women, 24% having any comorbidity) and structural knee OA in 12%. Clinical knee OA was associated with 9.60 (95% CI 3.70; 15.50) MET hours per week more physical activity, vs no clinical knee OA. Structural knee OA was associated with 3.97 (-7.82; 15.76) MET hours per week more physical activity, vs no structural knee OA. In clinical knee OA, physical activity was not associated with knee pain, function or HRQoL. CONCLUSIONS: Knee OA was not associated with lower physical activity, and in knee OA physical activity was not associated with patient-reported outcomes. Future research should indicate the optimal treatment advice regarding physical activity for individual knee OA patients.

Patients', healthcare providers', and insurance company employees' preferences for knee and hip osteoarthritis care: a discrete choice experiment.

OBJECTIVE: To determine patients', healthcare providers', and insurance company employees' preferences for knee and hip osteoarthritis (KHOA) care. DESIGN: In a discrete choice experiment, patients with KHOA or a joint replacement, healthcare providers, and insurance company employees were repetitively asked to choose between KHOA care alternatives that differed in six attributes: waiting times, out of pocket costs, travel distance, involved healthcare providers, duration of consultation, and access to specialist equipment. A (panel latent class) conditional logit model was used to determine preference heterogeneity and relative importance of the attributes. RESULTS: Patients (n = 648) and healthcare providers (n = 76) valued low out of pocket costs most, while insurance company employees (n = 150) found a joint consultation by general practitioner (GP) and orthopaedist most important. Patients found the duration of consultation less important than healthcare providers and insurance company employees did. Patients without a joint replacement were likely to prefer healthcare with low out of pocket costs. Patients with a joint replacement and/or low disease-specific quality of life were likely to prefer healthcare from an orthopaedist. Patients who already received healthcare for knee/hip problems were likely to prefer a joint consultation by GP and orthopaedist, and direct access to specialist equipment. CONCLUSIONS: Patients, healthcare providers, and insurance company employees highly prefer a joint consultation by GP and orthopaedist with low out of pocket costs. Within patients, there is substantial preference heterogeneity. These results can be used by policy makers and healthcare providers to choose the most optimal combination of KHOA care aligned to patients' preferences.

The clinical and radiographic course of early knee and hip osteoarthritis over 10 years in CHECK (Cohort Hip and Cohort Knee).

OBJECTIVE: To describe the radiographic and symptomatic course in subjects with hip or knee complaints suspected of early osteoarthritis (OA). DESIGN: CHECK (Cohort Hip and Cohort Knee) is a multicenter, prospective observational cohort study of 1,002 subjects with first complaints in knee(s) and/or hip(s) (age 56 ± 5 years; 79% female; body mass index (BMI) 26 ± 4 kg/m2). Visits took place at baseline and at 2, 5, 8, and 10 year follow-up. At each visit, questionnaires were administered, physical examination performed, and X-ray images obtained. Clinical OA was defined according to the clinical American College of Rheumatism (ACR) criteria. Radiographic OA (ROA) was defined as Kellgren and Lawrence score (K&L) ≥2. RESULTS: 83% of the subjects reported knee pain, 59% hip pain, and 42% reported both hip and knee pain at baseline. 85% of the subjects completed 10-year follow-up. Pain scores remained rather stable over time, although individual scores fluctuated. A total of 138 subjects never fulfilled the clinical American College of Rheumatology (ACR) criteria. 60% (n = 601) had ROA in one or both knees, and 51% (n = 513) had ROA in one or both hips at 10 years. Only 13.5% of the subjects did not develop ROA after 10 years. Most joint replacements (n = 52 (57%)) took place in subjects with multiple affected joints. CONCLUSIONS: The symptomatic course in subjects with hip or knee complaints suspected of OA remained fairly stable on population level, though individual scores fluctuated. The radiological course was progressive, with joint replacements particularly in subjects with both hip and knee OA.

Osteoarthritis year in review 2017: rehabilitation and outcomes.

OBJECTIVE: The purpose of this systematic review was to describe studies examining rehabilitation for people with osteoarthritis (OA) and to summarize findings from selected key systematic reviews (SRs) and randomized controlled trials (RCTs). DESIGN: A systematic search was performed using Pubmed, Embase and Cochrane databases from April 1st 2016 to May 15th 2017 using the terms 'osteoarthritis', 'randomized controlled trial', and 'systematic review'. Inclusion criteria were: clinically or radiologically diagnosed patients with OA, rehabilitation treatment, RCT or SRs. A selection of the included studies is discussed based on study quality and perceived importance to the field; including those that are innovative, inform the direction of the field or generate controversy. Methodological quality of the included studies was assessed using the PEDro-scale for RCTs and the Amstar guideline for SRs. RESULTS: From 1211 articles, 80 articles met the eligibility criteria including 21 SRs and 61 RCTs. The median of the methodological quality of the SRs and RCTs was 7 (2-9) and 6 (3-10), respectively. The studies were grouped into several themes, covering the most important rehabilitation fields. CONCLUSIONS: Striking is the small number of studies investigating another joint (18%) than the knee (82%). Exercise is the most common treatment evaluated and should be accompanied with education to effectuate a behavioural change in physical activity of people with OA. No new insights in the field of braces (or orthoses) and in the field of acupuncture were found.

Crepitus is a first indication of patellofemoral osteoarthritis (and not of tibiofemoral osteoarthritis).

OBJECTIVE: The patellofemoral joint (PFJ) is important in early detection of knee osteoarthritis (OA). Little is known about the relationship between specific clinical findings and PFJ Magnetic resonance Imaging (MRI) features. The objective was to examine the relationship between (early) clinical findings and PFJ MRI features in females (45-60 years) without knee OA (PFJ or tibiofemoral joint (TFJ) OA) based on a recently suggested MRI definition. METHODS: MRIs of knees of women of a sub-study of the Rotterdam Study were scored with semi-quantitative scoring. Specific patellar tests were performed on physical examination. Current knee pain and history of patellar knee pain were reported. Binomial logistic generalized estimated equations were used to determine the association between clinical findings of OA and PFJ MRI features. All associations were adjusted for age, body mass index (BMI) and TFJ MRI features. RESULTS: In 888 women (1776 knees, mean age: 55.1 years and mean BMI: 27.0 kg/m(2)) we found significant associations between crepitus and all PFJ MRI features (Odds ratios (OR) range: 2.61-5.49). A history of patellar pain was significantly associated with almost all PFJ MRI features (ORcartilage: 1.95; ORcysts: 1.86; ORbone marrow lesions: 1.83), except for osteophytes. No significant associations were found between the clinical findings and TFJ MRI features. CONCLUSION: Crepitus and history of patellar pain are clinical findings that indicate PFJ lesions seen on MRI. These tests could help to indicate signs of PFJOA. Follow-up data needs to confirm whether these tests have an additional diagnostic value for early knee OA in PFJ or TFJ.

Sensitivity and associations with pain and body weight of an MRI definition of knee osteoarthritis compared with radiographic Kellgren and Lawrence criteria: a population-based study in middle-aged females.

OBJECTIVES: Is a magnetic resonance imaging (MRI) definition for tibiofemoral osteoarthritis [(TFOAMRI) (definite osteophyte and full-thickness cartilage loss (or a combination of these factors with other MRI osteoarthritis (OA) features)] more sensitive to detect structural OA compared with the Kellgren & Lawrence (K&L) grading? And which definition shows the strongest association with (1) knee pain at baseline, (2) persistent knee pain during 2-year follow-up, (3) new onset of knee pain ±2 years later, and (4) body mass index (BMI). DESIGN: Of 888 females of the open population Rotterdam Study, radiographs and MRI of both knees were assessed for knee OA defined by K&L ≥ 2 and TFOAMRI. Pain in or around the knee is measured at baseline and ±2 years later. GEE analyses are used for the associations. RESULTS: Of 1766 knees, 77 knees (4%) were diagnosed with K&L ≥ 2, whereas 160 knees (9%) met the TFOAMRI criteria. Only 43 knees met both definitions (34 knees were graded with K&L ≥ 2 and no TFOAMRI and 117 knees met only the TFOAMRI criteria). The association between the definitions and knee pain at baseline was higher when TFOAMRI was included [TFOAMRI alone: odds ratio (OR) = 2.83 (95% confidence interval (CI): 1.84-4.36); TFOAMRI & K&L ≥ 2: OR = 6.28 (95% CI: 2.99-13.19)] than for K&L ≥ 2 alone (OR = 1.83 (95% CI: 0.63-5.32)). This was similar for the association between the definitions and persistent knee pain, and between the definitions and BMI. CONCLUSIONS: TFOAMRI detects more cases of knee OA than K&L ≥ 2. Together with a better content validity and at least equal construct validity, we conclude that the TFOAMRI definition for knee OA is more sensitive in detecting structural knee OA.

Inter-observer reliability for radiographic assessment of early osteoarthritis features: the CHECK (cohort hip and cohort knee) study.

OBJECTIVE: To calculate inter-observer reliability between four different trained readers and an experienced reader on early radiographic osteoarthritis (OA) features in our early OA cohort hip and cohort knee (CHECK) cohort. METHODS: Four readers were trained by a radiologist and experienced reader to score radiographic OA features. After this training they scored the CHECK cohort. Of the 1002 participants, 38 were scored by all readers. Five different angle radiographs (three for the knee, two for the hip) at three different time points were scored and compared. Inter-observer reliability was evaluated between each of the four trained readers and the experienced reader. Separate radiographic OA features and of overall Kellgren & Lawrence (K&L) scores. In addition, reliability of progression of radiographic was determined in K&L scores and joint space narrowing (JSN). RESULTS: For hip and knee there was substantial inter-observer reliability on overall K&L scores. In the knee, JSN was scored with fair to moderate reliability, osteophytes with moderate to nearly perfect reliability, and other features with fair to substantial reliability. In the hip, reliability ranged from substantial to nearly perfect. Moderate inter-observer reliability was found for progression of OA in both knee and hip, with slightly better reliability for progression based on K&L scores than on separate features. CONCLUSION: Good inter-observer reliability can be achieved between trained readers and an experienced reader. Although JSN in the knee is scored with lower inter-observer reliability than osteophytes, this does not seem to influence overall K&L scoring. In the hip all features showed good reliability.

How to define subregional osteoarthritis progression using semi-quantitative MRI osteoarthritis knee score (MOAKS).

OBJECTIVE: Recently, the MRI Osteoarthritis Knee Score (MOAKS), a new semi-quantitative magnetic resonance imaging (MRI) scoring tool, was introduced by a panel of experienced researchers in osteoarthritis (OA). The MOAKS is primarily applicable to quantify OA status, since the interpretation of change in the MOAKS features was not described. In order to enable longitudinal evaluation, we propose definitions for progression and improvement of the main MOAKS features. METHOD: Clear definitions for progression and improvement of the main MOAKS features are given in this brief report. 687 baseline and 30 months follow-up MRIs of the knees of 348 overweight and obese middle-aged women, free of OA at baseline, were scored using the MOAKS. Baseline prevalence and the change of MOAKS features after 30 months follow-up, based on our definitions for progression and improvement, are presented. RESULTS: The proposed definitions showed 3% to 23% progression and 0% to 11% improvement in the MOAKS features during the 30 months follow-up. Overall, progression rates were higher in the medial than in the lateral tibiofemoral (TF) joint. Progression of bone marrow lesions (BMLs) and cartilage defects was highest in the patellofemoral (PF) joint. Inter-rater reliability of the MOAKS scores was moderate to nearly perfect (PABAK 0.77-0.88), with high percentage of agreement overall (89-94%). CONCLUSION: This brief report presents definitions for progression and improvement of the main MOAKS features for the longitudinal evaluation of knee OA features on MRI. We advocate uniform usage of the proposed definitions across studies, but welcome suggestions for optimization.

Patterns of knee osteoarthritis management in general practice: a retrospective cohort study using electronic health records.

OBJECTIVE: This study determined patterns of knee osteoarthritis (OA) management by general practitioners (GPs) using routine healthcare data from Dutch general practices from 2011 to 2019. DESIGN: A retrospective cohort study was conducted using the Integrated Primary Care Information database between 2011 and 2019. Electronic health records (EHRs) of n = 750 randomly selected knee OA patients (with either codified or narrative diagnosis) were reviewed against eligibility criteria and n = 503 patients were included. Recorded information was extracted on GPs' management from six months before to three years after diagnosis and patterns of management were analysed. RESULTS: An X-ray referral was the most widely recorded management modality (63.2%). The next most widely recorded management modalities were a referral to secondary care (56.1%) and medication prescription or advice (48.3%). Records of recommendation of/referral to other primary care practitioners (e.g. physiotherapists) were found in only one third of the patients. Advice to lose weight was least common (1.2%). Records of medication prescriptions or recommendation of/referral to other primary care practitioners were found more frequently in patients with an X-ray referral compared to patients without, while records of secondary care referrals were found less frequently. Records of an X-ray referral were often found in narratively diagnosed knee OA patients before GPs recorded a code for knee OA in their EHR. CONCLUSION: These findings emphasize the importance of better implementing non-surgical management of knee OA in general practice and on initiatives for reducing the overuse of X-rays for diagnosing knee OA in general practice.

Development of radiological knee osteoarthritis in patients with knee complaints.

OBJECTIVES: It is currently impossible to identify which patients with knee complaints presenting to the general practitioner will develop knee osteoarthritis (OA) pathology at a later stage. This study examines the determinants for developing OA pathology on x-ray in patients with knee complaints but no radiological OA at baseline in the painful knee. METHODS: Data from the prospective Rotterdam cohort study (including subjects aged ≥55 years) were used. Analysis was performed on 623 subjects with knee complaints at baseline and their data at 6-year follow-up (T1; n=607) and at 11-year follow-up (T2; n=457). At baseline, none had radiological OA (rOA=Kellgren and Lawrence (KL) grade ≥2) in the painful joint. At follow-up, predictors for rOA were determined using multivariate ordinal logistic regression analysis. RESULTS: At T1, 8.5% of the group had developed knee rOA and, by T2, this had increased to 23%. Determinants remaining significant in the multivariate analysis were female gender (OR 1.95, 95% CI 1.15 to 3.36), other joint complaints (OR 2.22, 95% CI 1.12 to 4.35) and KL grade 1 at baseline in the painful knee joint (OR 7.14, 95% CI 4.55 to 11.1). All outcomes are adjusted for all included determinants. CONCLUSION: The best predictors of development of knee rOA are a combination of female gender, other joint complaints and KL grade 1 in the painful joint. KL grade 1 in combination with knee pain should be considered as early OA in patient management.

Variation in joint shape of osteoarthritic knees.

OBJECTIVE: To investigate the role of joint shape in knee osteoarthritis (OA) by determining which aspects of bone shape are different in OA knees compared with control knees. METHODS: Using a statistical shape model, we compared radiographs showing the shape of OA knees with radiographs showing the shape of control knees in a population of 609 women (1,218 knees) extracted from the Rotterdam Study. Furthermore, we used magnetic resonance imaging to compare the shape of knees with cartilage defects with the shape of knees without cartilage defects. RESULTS: Three statistical shape modes, referring to 3 distinct aspects of the shape of the knee, were significantly associated with the presence of radiographic OA (modes 2, 4, and 15). Mode 2 reflected the width of the femoral and tibial bones, which was increased in patients with OA. Knees with cartilage defects also had wider femoral and tibial bones compared with knees without cartilage defects. Mode 4 reflected the variation in flexion of the knee during radiography. OA knees were more extended compared with control knees. Mode 15 showed that patients with OA had an elevated lateral tibial plateau, which was associated with pain. CONCLUSION: In women, knees with OA were wider, more extended during radiography, and had an elevated lateral tibial plateau. These results show that the shape of the knee is involved in OA, which might lead to novel imaging biomarkers to monitor or predict knee OA.

Impact of different descriptions of the Kellgren and Lawrence classification criteria on the diagnosis of knee osteoarthritis.

OBJECTIVES: Although the Kellgren and Lawrence (K&L) criteria for defining radiological osteoarthritis are widely used in epidemiological and clinical studies, the authors previously documented the existence of five different versions of these criteria. This study identifies the impact of the use of alternative versions of the K&L criteria and evaluates which description has the highest association with knee complaints. METHODS: Two readers scored most radiographs of the knees of participants of the Rotterdam Study with the original K&L description (90%). In addition, each alternative description was used in a random part (20%) of the radiographs. The authors calculated reproducibility of all descriptions, and compared sensitivity and specificity of the alternative descriptions for three cut-off points with the original description as reference standard (K&L≥1, K&L≥2 and K&L≥3). The authors calculated κ statistics to compare agreement between the original and alternative descriptions, and evaluated the association with knee complaints. RESULTS: The dataset comprises radiographs of knees of 3071 people. For cut-off K&L≥1 all four alternatives classified more people as having osteoarthritis than the original description; κ was low, and sensitivity and specificity were moderate to good. For cut-offs K&L≥2 and K&L≥3 there was little difference in the number of cases and κ, sensitivity and specificity were good to perfect. The original description and alternative 3 showed the strongest association with knee complaints. CONCLUSIONS: The different descriptions of the K&L criteria have impact on the classification of osteoarthritis in the lowest grade (K&L≥1). All descriptions have strengths and weaknesses. It depends on the purpose which is the best description.

Prevalence of small osteophytes on knee MRI in several large clinical and population-based studies of various age groups and OA risk factors.

Objective: Osteophytes, also small ones, are an important imaging feature of OA. However, due to their high prevalence on MR, the question has arisen whether these are truly pathophysiologic features of early OA, a result of physiologic aging, or rather a merely transient phenomenon. The aim of this study was to explore the prevalence of osteophytes on MR in various locations of the knee, with special emphasis on small osteophytes, across multiple large studies conducted in our institution comprising a wide range of subjects at different ages. Method: Retrospective explorative study of the prevalence of osteophytes, particularly grade 1 according to MOAKS, among four studies with a wide variety in age and OA risk factors. Results: A large number of grade 1 osteophytes were found in all four studies. The largest number of osteophytes were present in the youngest age group of <30 years (69.6%) compared to 36.8% in the age group of ≥30 â€‹< â€‹50 years and 54,3% when aged ≥50 years, of which most were grade 1 osteophytes. Conclusion: Small osteophytes are highly prevalent among populations with varying age and OA risk factors, in particular among young subjects without other OA features. This might suggest that these "osteophytes" do not necessarily represent early OA, but rather indicate a transient physiologic phenomenon.