D. Schiphof

Differences in descriptions of Kellgren and Lawrence grades of knee osteoarthritis

Objective: Correct application of the Kellgren and Lawrence (K&L) classification system is difficult due to inexact wording of the descriptors. We summarised different descriptions and searched for evidence on the impact of such variations on classification of knee osteoarthritis (OA) in epidemiological studies. Methods: We searched Medline/Pubmed (1966 to August 2006) for studies of epidemiological cohorts that professed use of the original K&L scale (grades 0–4, with 0 being normal and 4 severe OA), and recorded their descriptions of the five grades. The descriptions were compared with each other and with the original description. Results: We identified five different descriptions. In grade 2, often used as a cut-off to classify OA, one description replaced “definite osteophytes and possible narrowing of joint space” (K&L) by “definite osteophyte, unimpaired joint space”. Another description for grade 2 was “minimal osteophytes, possible narrowing, cysts, and sclerosis”. In some cohort studies, descriptions changed during follow-up. None of the included articles studied the impact of the use of different descriptions. Conclusion: Major OA cohort studies disagree between each other and even among themselves on the definition and grading of disease according to the original K&L system. The impact of this disagreement warrants further study, but consensus urgently needs to be reached on a single valid and feasible classification system.

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.

No clear association between female hormonal aspects and osteoarthritis of the hand, hip and knee: a systematic review

OBJECTIVE Incidence of OA rises steeply in women of age >50 years; the climacteric period for women. The simultaneous occurrence of these events suggests an association between OA and changes in female hormonal aspects. This systematic review studies the assumed association between OA and aspects concerning the fertile period (duration, endogenous hormones, age at menarche/menopause) and the menopause [menopausal status, years since menopause (YSM) and surgical menopause]. METHODS Medline and EMBASE were searched for articles assessing associations between hand/hip/knee OA and female hormonal aspects. Methodological quality was assessed systematically, and results were summarized in a best-evidence synthesis. RESULTS Sixteen studies were included in the present study. For most hormonal aspects no association was found. Conflicting evidence was found for an association of age at menarche with Herberdens nodes (HNs) and hand ROA, YSM with knee ROA and ovariectomy with hip OA. An increased risk was seen for low estradiol serum levels in the early follicular phase with incident knee ROA, age at menarche being < or =11 years old with total hip replacement, being post-menopausal and YSM with the presence of HN. A protective effect was seen for age at menopause being > or =52 years with total knee replacement. Evidence level was limited for all. CONCLUSIONS The assumed relationship between the female hormonal aspects and OA was not clearly observed in this review. The relationship is perhaps too complex, or other aspects, yet to be determined, play a role in the increased incidence in women aged >50 years.

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.

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.

Factors for Pain in Patients With Different Grades of Knee Osteoarthritis

Discordance between having pain and radiologic osteoarthritis (OA) is a well‐established fact. It is suggested that this particularly applies to the less severe grades of OA. However, some people with a Kellgren/Lawrence (K/L) grade of 3 or 4 for OA are without pain. This study aimed to identify factors and differences in the factors associated with pain in persons with different grades of knee OA.

Good reliability, questionable validity of 25 different classification criteria of knee osteoarthritis: a systematic appraisal.

OBJECTIVES Despite extensive epidemiological and clinical research, there is no consensus on classification criteria to define knee osteoarthritis (OA). No gold standard is available and many different definitions are used. For future research and interpretation of epidemiological studies, we aimed to evaluate reliability and validity of commonly used classification criteria. STUDY DESIGN AND SETTING Systematic searches were performed in Medline/Pubmed and Embase for articles evaluating reliability, construct validity, and content validity of knee OA classification criteria. RESULTS In 18 articles, 25 classification criteria were found that could be summarized in three categories (radiological clinical and radiological combined classification criteria, and clinical classification criteria). No classification criteria based on magnetic resonance imaging could be included. In general, intra- and interrater reliabilities were good. Construct validity was low when radiological criteria were compared with clinical classification criteria. Associations between classification criteria and symptoms and risk factors like pain and obesity were moderate. CONCLUSION More research is needed to investigate the impact of different classification criteria in epidemiological research and to reach consensus about which criteria should be used to define knee OA. Meanwhile, to create uniformity in epidemiological research we recommend separate lesion scoring, overall scoring, and pain registration to define knee OA.

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.

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.