病史:患者,男,21岁。左膝部疼痛2年余,时轻时重,进行对症治疗,未做特殊处理。入院前,因行走中不慎摔倒,跌伤左膝,致使局部症状加剧而入院。体检:发育营养好,神志清醒,被动体位,双侧胸部无畸形,脊柱、双上肢及右下肢无异常发现。左膝部肿胀,活动受限,压痛明显,行走困难。 History: Patient, male, 21 years old. The left knee was painful for more than two years, when light and heavy, and symptomatic treatment was performed without special treatment. Before admission, he fell to his left knee due to accidental fall during walking, resulting in increased local symptoms and hospital admission. Physical examination: good developmental nutrition, clear mind, passive posture, no abnormalities in both sides of the chest, no abnormalities in the spine, upper limbs, and right lower limbs. The left knee is swollen, activity is limited, tenderness is evident, and walking is difficult.