Inter- And Intra-Observer Concordance Of The Modified Kellgren And Lawrence Scale For Knee Osteoarthritis By Compartments In Patients Of The University Hospital Fundación Santa Fe De Bogotá, Colombia. Cristal Castellanos 1, Abelardo Camacho 2, Klaus Mieth 3, Gamal Zayed 3, German Carrillo 3, Oscar Rivero 4, Rafael Gómez 4, Sara Jaimes 4 1. Orthopedist Rosario University 2. Orthopedics Resident Rosario University, Knee section, Orthopedics and Trauma Department, University Hospital Fundación Santa Fe de Bogotá. 3. Knee surgeon, Knee section, Orthopedics and Trauma Department University Hospital Fundación Santa Fe de Bogotá. 4. Radiologist, Musculoskeletal System, Radiology Department, University Hospital Fundación Santa Fe de Bogotá.
Conflict of interests Authors Cristal Castellanos Abelardo Camacho Klaus Mieth Gamal Zayed Germán Carrillo Oscar Rivero Rafael Gomez Sara Jaimes Speaker for Smith & Nephew
Introduction and Justification The radiological classification of Kellgren & Lawrence (KL), has been been used frequently in the description of the articular state in knee osteoarthritis. This classification does not evaluate each compartment individually. The osteoarthritis of each of the compartments affects the knee in a different way, in respect to the quality of life and the therapeutic approach. The individual evaluation of osteoarthritis by compartments could give a more precise and standardized image of the magnitude of joint damage.
General Objective Description of the inter-rater and intra-rater reliability modified Kellgren & Lawrence classification (KLM) of the Specific Objectives Description of a modification of the Kellgren & Lawrence classification by knee compartments Description of a method for KLM interpretation Description of the inter-rater reliability of KLM Description of the intra-rater reliability of KLM
Materials and methods A modification of the scale by informal consensus of experts after a structured review of literature Study of reliability of a diagnostic test Population Knee X-rays, comparative AP with support, lateral in 30 of flexion, and axial projection of the patella. Sample size: Alpha error 5%, Beta error 20%, Number of evaluators: 6, Kappa 0.1 Minimal amount: 118 radiographs 210 radiographs by means of random selection distributed in 7 age ranges, from 18 years old. Exclusion criteria: congenital or traumatic knee deformity, presence of osteosynthesis or prosthetic material.
Materials and methods Evaluators: 2 orthopedic knee surgeons with more than 10 years of experience 2 knee orthopedic surgery fellows 2 radiologists specialized in musculoskeletal system with more than 10 years of experience Reliability analysis: agreement Krippendorff s alpha coefficient Poor 0 Low 0.1-0.2 Reasonable 0.21-0.4 Moderate 0.41-0.6 Substantial 0.61-0.8 Almost perfect 0.81 1
Results Modification of the classification (on green most relevant criteria) KLM GRADE Item to evaluate NORMAL UNCERTAIN MILD MODERATE SEVERE 0 1 2 3 4 Joint space (Subjective) Normal Normal Minimum loss <50% Moderate loss >50% Loss near to 100% Osteophyte (Incluiding spines) Cortical or subchondral line Absence Minimum Minimum Moderate or significative Normal Normal Normal Irregular Significative Irregular and/ or depressed Subchondral spongy Normal Normal Sclerosis or normal Cysts and/or sclerosis Cysts and/or sclerosis
Results X-rays represent the full spectrum of articular disease due to osteoarthritis Population distribution N (X-rays) 210 Age Mean 56 years (18 96) Gender Laterality 65% F 35% M 53% Left 43% Right
Results Intra-rater reliability Krippendorff s alpha coefficient Poor Low Reasonable Moderate Substantial Almost perfect Knee surgeon 1 Knee surgeon 2 Fellow 1 Fellow2 Radiologist Radiologyst 1 Radiologist Radiologyst 2 0 0.2 0.4 0.6 0.8 1 Patellofemoral Lateral PF FTE compartment FTI Medial compartment
Results Inter-rater reliability Krippendorff s alpha coefficient Poor Low Reasonable Moderate Substantial Almost perfect Radiologists Radiologysts Fellows Knee surgeons Orthopedists Ortopedia 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Patellofemoral Lateral PFcompartment FTE FTI Medial compartment
Conclusions The modified Kellgren and Lawrence classification is a standardized tool that allows an accurate description the joint state of the knee. The training for the use of the scale is feasible as shown by the interrater reliability of the knee fellows. The orthopedists intra-rater and inter-rater reliability observed, allows us to recommend the use of this classification. The independent approach of each compartment of the knee improves the accuracy in the description of the pathology.
Conclusions Two patients classified as grade 4 in the classic Kellgren & Lawrence scale, have different topographic compromise, their symptoms and medical approach could be different. 4 4 2 4 2 4 1 1
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