<s>[INST] I hit my knee with a wooden stick today while my leg was straight and pain shot through my knee and made it impossible to walk. But after awhile i could bend it again but I can't lock my knees without experiencing pain in the are above my knee cap. What is it? [/INST] Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Possible causes of knee pain after injury may be due to patellar fractures or cartilage injury of patellofemoral joint or tendinitis of patella or injury to meniscus or cruciate ligaments. Until examination is done it is difficult to say what it is. Take rest, use cold and warm compression, use tablet Ultracet twice a day for five days. If symptoms not improved please consult your doctor he will examine and take X-ray then treat you accordingly. Take care. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Penchila Prasad Kandikattu </s>