Hi, Thank you for providing the brief history of you. A thorough musculoskeletal assessment is advised followed with an MRI of knee. As you landed on the flat foot, there might be a serious issues with the ligaments of the knee, or even may be a tibial spine fracture. Undergoing a proper and in depth musculoskeletal assessment and MRI will help alot. Also, undergoing physical therapy will help reduce the pain and inflammation with the physical agents like - therapeutic ultrasound therapy and TENS therapy. Starting to perform slow static exercises for quadriceps and hamstring will help regain the muscle strength, since post any injury, there leads to weakness in the muscles and the mobility is restricted completely. Also, on a later stages exercises will be made more focused on making the knee stronger to avoid future problems, Usually, any knee injury occurred in the past may lead to the early osteoarthritis of the knee, so getting a proper assessment and rehabilitation is always the choice for the patients benefits by good medical practitioner. Regards Jay Indravadan Patel