Should i have a knee arthroscopy?

I've having problems with my knee for the past year or so. I was kicking some heavy timbers with the side of my foot to straighten them up when I felt a sharp pain in my knee. I knew I messed something up. I made a doctors Apt. that same day, and by the time I got to the doctors office I couldn't walk. They put me in a wheelchair and wheeled me up to the Dr. office. The doctor had me get some X-rays gave me some pain pills and advised me to stay home for a week or so. Oh he also gave me a shoot of cortisone. after a few weeks the pain went away and the x-rays came back negative. A few months down the road the pain came back and again I could hardly walk. I went back to the doctor and he gave me another shot and some more pills. Again the pain somewhat went away. Let me ad that I am a superintendent for a construction company so I have to walk around the job-site all day. Lately its been acting up more and more. we finally had on MRI done and I went back to the DR. to go over the results. He told me that I have some broken cartilage, which is bruising the bone, and also thinning cartilage. He told me that I could either have a knee arthroscopy or just live with the pain. He said the knee arthroscopy might help and might not. Since my cartilage is already thinning I am concerned about taking out any more causing my knee to be bone on bone. I am wondering if a pain management plan might be better for me at this time than the arthroscopy. As I am only 31 years old, and I have a felling I am going to have knee replacement in the future. I guess bad knees run in the family. my dad is 55 and he recently had both of his knees replaced. Any suggestions you might have to help me make up my mind would be appreciated