Full-limb and knee radiography assessments of varus-valgus alignment and their relationship to osteoarthritis disease features by magnetic resonance imaging.

OBJECTIVE: To examine the correlation between hip-knee-ankle and femur-tibia radiograph angles, calculate the offset of the femur-tibia angle with respect to the hip-knee-ankle angle, calculate the sensitivity and specificity and area under the receiver operating characteristic (ROC) curve of the femur-tibia angle, and examine the relationship of malalignment by each approach with osteoarthritis (OA) tissue pathology in the mechanically stressed compartment using magnetic resonance imaging (MRI). METHODS: Individuals with knee OA underwent full-limb and knee radiographs and knee MRI. Linear regression was used to determine if the 2 angles differed systematically and to identify the cutoff. Alignment means for MRI grades were compared using Dunnett's t-test. RESULTS: In the 146 participants (109 women, mean age 70 years, body mass index 30.6 kg/m(2)), femur-tibia and hip-knee-ankle angles correlated (r = 0.86; 95% confidence interval [95% CI] 0.81, 0.90). On average, the femur-tibia angle was 3.4 degrees more valgus (3.0 degrees in women and 4.7 degrees in men); after correction, its sensitivity and specificity (to predict the hip-knee-ankle angle) were 0.84 and 0.84 for identifying varus and 0.98 and 0.73 for valgus, respectively. The area under the ROC curve (95% CI) was 0.91 (0.86, 0.96) for varus and 0.94 (0.89, 0.99) for valgus. Varus severity worsened comparably with each alignment measure as medial lesion score on MRI worsened. Laterally, as lesion score worsened, comparably worse valgus was seen with either assessment approach. CONCLUSION: In knee OA, the knee radiograph femur-tibia and full-limb radiograph hip-knee-ankle angles were correlated. The femur-tibia angle, corrected for mean offset, was sensitive, specific, and had excellent discriminative ability for identifying varus and valgus alignment evidenced by area under the ROC curve. The relationship between alignment and specific OA MRI features was comparable with the 2 approaches. Use of the femur-tibia angle, corrected for offset, should be considered in research and clinical settings.

Epidemiology of osteoarthritis: an update.

Osteoarthritis is the most common form of arthritis and is a leading cause of disability in the elderly. Given the anticipated increase in osteoarthritis prevalence, the need to identify risk factors for incident osteoarthritis, osteoarthritis progression, osteoarthritis-associated physical function decline, and disability is an especially high priority. Findings have implicated several factors, including genetic factors, aging, joint deformity and injury, obesity, and hormonal deficiencies in the pathogenesis of osteoarthritis. Recent studies have identified risk factors associated with progression of the disease including varus-valgus alignment, bone marrow edema lesions, varus thrust, a reduced hip abduction moment, and obesity. Predictors of function decline in osteoarthritis include lower self-efficacy, knee laxity, less aerobic exercise, worse joint proprioception, and greater knee pain.

Damage control in rheumatoid arthritis. Hard-hitting, early treatment is crucial to curbing joint destruction.

Right from the onset, rheumatoid arthritis is an aggressive disease that can quickly alter joint structure and integrity. Such rapid pathogenesis requires that the diagnosis be established early and aggressive therapy initiated swiftly. In this article, Drs Issa and Ruderman describe what is known about the cause, progression, and outcomes of rheumatoid arthritis. They review the steps toward its diagnosis and urge that treatment be started promptly--to both contain disease and reduce joint destruction as soon as possible.