Chondral Lesion of the Knee

This study will examine whether using bone marrow aspirate (BMA) during knee arthroscopy surgery can improve patient outcomes. The investigators will enroll 50 patients who need knee arthroscopy surgery for meniscus injuries or cartilage damage. Like flipping a coin, patients will be randomly assigned to one of two groups of 25 patients each. One group will receive standard arthroscopic surgery plus an injection of bone marrow aspirate, while the other group will receive standard surgery plus a saline (salt water) injection. During surgery, for patients in the treatment group, approximately 4mL (less than one teaspoon) of bone marrow will be taken from their hip bone using a special needle system. A small amount (1mL) will be sent to the laboratory for testing. Patients will be followed for 12 months after surgery and will complete questionnaires about their pain levels and knee function at several time points: before surgery, 2 weeks, 6 weeks, 3 months, 6 months, and 12 months after surgery. These questionnaires will ask about pain, daily activities, and overall improvement.