Bone bruise in magnetic resonance imaging strongly correlates with the production of joint effusion and with knee osteoarthritis.

BACKGROUND: The findings of magnetic resonance imaging (MRI) have not been studied systematically in patients with osteoarthritis (OA). The objective here was to compare MRI findings with radiological findings in patients with knee pain and to identify factors that influence the progression of OA of the knee. METHODS: Of 212 patients with knee pain and MRI of the knee joint, 161 patients were selected for the study after exclusion of cases of trauma and other arthritides. MRI was used to evaluate the presence and degree of bone bruise, hydrarthrosis, and injuries to the cruciate ligament and meniscus. Bone bruise was classified into four types, and hydrarthrosis into four grades. Radiologically, OA progression in the femorotibial and patellofemoral joints was analyzed according to the Kellgren-Lawrence classification. Age was divided into four groups based on distribution quartiles. Logistic regression analysis and a generalized linear model with Poisson regression were used to analyze correlations among these factors. RESULTS: Bone bruise was present in 87 cases, hydrarthrosis in 100, cruciate ligament injury in 20, and meniscus injury in 98. The presence of bone bruise was not related to age, cruciate ligament injury, meniscus injury, nor to OA of the patellofemoral joint, but was related to hydrarthrosis and to OA of the femorotibial joint. Femorotibial OA was much more strongly associated with bone bruise than with hydrarthrosis. Furthermore, analyzing the relation between the types of bone bruise and the degree of hydrarthrosis using a generalized linear model with Poisson regression, there was a positive correlation between the grade of bone bruise and the amount of hydrarthrosis. CONCLUSIONS: A factor associated with the degree of osteoarthritis of the knee is bone bruise observed on MRI. The degree of hydrarthrosis is related to the grade of bone bruise, but is not linked to the degree of osteoarthritis.

Vertebral body fracture of the lumbar spine in elderly women: more severe in osteoarthritis of the knee than in femoral neck fracture.

This study investigated bone fragility by comparing fractures of the vertebral body of the spine in elderly women receiving total knee replacement (TKR) (group 1) due to severe osteoarthritis of the knee and those with femoral neck fractures (group 2) attributable to osteoporosis. Forty-two women each were selected retrospectively for group 1 and prospectively for group 2. Patient age ranged from 64-83 years. Vertebral body fractures of the lumbar spine were significantly more severe in group 1 than in group 2 (P<.001). Patients undergoing TKR due to osteoarthritis of the knee had systemic bone fragility, which included the spine.