Objectives To identify risk factors for progression of knee joint osteoarthrosis (OA) in the first 5 years of disease.
Methods Prospective 5-year study included 110 female-patients with primary knee OA (CCR criteria), in 52 of them disease duration did not exceed 5 years, (mean age – 59,11±8,95 years). All relevant patients' data, including anthropometric parameters, case history, evaluation of pain intensity by VAS, knee joint status and therapeutic modalities used during the follow up period were recorded in individual patient's file. Instrumental diagnostic methods used in each patient included plain radiography of knee joints (gonarthrosis stage was classified by Kellgren J.- Lawrence J. scale), dual energy X-ray absorptiometry (DEXA) of the lumbar spine, femoral neck and of subchondral bone of the hip and tibia, ultrasound (US) and MRI examination of knee joints. First OA stage was documented in 22 (42,3%) out of 52 patients, 2-nd - in 24 (46,2%) patients, 3d stage - in 6 (11,5%) patients.
Results During 5 year follow up radiographic progression of knee OA was documented in 14 patients (Group with progression), while in 38 patients radiographic stage remained unchanged. Patients from both groups were similar in terms of age (58,29 ± 7,68 vs 56,05 ± 8,74 years), and disease duration (3,43 ± 1,34 vs 3,47 ± 1,33 years). Although, patients with OA progression had more intense knee pain when walking: 60,36 ± 18,33 vs 48,71 ± 17,81, p=0,043 (mm); higher BMI: 34,45 ± 4,60 vs 28,92 ± 4,92, p=0,001 (kg/m2); higher incidence of synovitis: 57,1% vs 18,4%, p=0,006 based on US findings, bone marrow edema in medial tibia aspect 64,3% vs 13,2%, p=0,001, based on MRI findings, and higher rate of serious medial condyle damage: 50,0% vs 7,8%, p=0,001 distinct from patients without OA progression. DEXA identified significantly higher absolute bone mineral density (BMD) values in the lumbar spine 0,91 ± 0,08 vs 0,82 ± 0,11, p=0,015 (g/cm2) and femoral neck 0,85 ± 0,09 vs 0,76 ± 0,08, p=0,007 (g/cm2), as well as higher BMD in the medial condyle of the tibia 0,95 (0,85–1,24) vs 0,75 (0,65–0,82), p=0,001 (g/cm2) as compared to patients without OA progression. Patients' re-examination in 5 years revealed similar statistically significant differences between the groups. Multifactorial analysis identified the following major risk factors, responsible for gonarthrosis progression: synovitis, bone marrow edema, and high BMD values in the medial condyle of the tibia, while intake of chondroitin sulfate (ChS) and glucosamine (GA) combination for more than 6 months a year during 5 years was identified as risk reduction factor. Based on identified factors and their coefficients a predictive model was suggested (with area under the ROC curve equal to 0,93), allowing to prognosticate the future course of the disease in an individual patient with high accuracy, i.e. 85,7%, sensitivity and 84,2% specificity.
Conclusions synovitis, bone marrow edema, and high subchondral BMD in the medial condyle of the tibia are the major risk factors responsible for progression of knee OA in patients with disease duration up to 5 years. While intake of ChS and GA had a positive impact on radiological OA progression.
Disclosure of Interest None declared