ObjectiveTo explore the correlation between the degree of bone marrow edema (BME) and the content change of tumor necrosis factor α (TNF-α) and matrix metalloproteinase 3 (MMP-3) and the knee pain symptoms in patients with bone contusion around the knee joint. MethodsThirty patients (30 knees) of bone contusion around the knee joint were chosen as the trial group between October 2009 and April 2012. According to visual analogue scale (VAS), 30 patients were divided into mild group (10 cases), moderate group (10 cases), and severe group (10 cases); according to MRI morphological changes, the patients were divided into type I group (12 cases), type Ⅱ group (11 cases), and type Ⅲ group (7 cases). Ten patients (10 knees) with soft tissue injury of the knee were chosen as control group. No significant difference was found (P>0.05) in gender, age, causes, side, and admission time after injury between 2 groups. The serum contents of MMP-3 and TNF-α were detected and statistically analysed between different degrees of pain groups and between different degrees of BME groups. Correlation was analysed between BME and inflammatory factor changes and VAS score. ResultsThe MMP-3 and TNF-α contents in trial group[(29.580±6.870) μg/L and (23.750±7.096) ng/L] were significantly higher than those in control group[(8.219±1.355) μg/L and (6.485±1.168) ng/L](t=9.686, P=0.000; t=7.596, P=0.000). The MMP-3 and TNF-α contents in patients with different degrees of pain and BME were significantly higher than those in patients of control group (P<0.05), and significant difference was found between patients with different degrees of pain (P<0.05), but no significant difference between patients with different degrees of BME (P>0.05). Multiple linear regression analysis showed that TNF-α content was significantly correlated with VAS score (P=0.000). ConclusionKnee pain symptoms are not related to the degree of BME in patients with bone contusion around the knee joint. Inflammatory factor TNF-α content is the main influence factor of knee joint pain symptoms.