Diagnosing Knee Sprains, Strains & Tears

Sports medicine orthopedists at NYU Langone Orthopedic Center use their expertise to diagnose knee injuries, including all types of sprains, strains, and tears. These injuries can occur when different parts of the knee stretch or tear.

Each part of the knee has a purpose, such as keeping the knee stable when walking, jumping, bending, or pivoting, or helping the body to absorb and distribute weight during movement. The parts of the knee that may be injured include muscles; ligaments, which are tough cords of tissue that connect and support bones; tendons, which are fibrous cords of tissue that attach muscle to bone; and the meniscus, a firm, smooth layer of cartilage that cushions the knee.

Symptoms of knee sprains and strains can include pain, bruising, swelling, or difficulty moving the joint. Symptoms of knee tears can vary, but they almost always include a sharp pain in the knee when you try to move it, swelling, and stiffness.

A more severe injury may prevent you from jumping or using your knee to pivot, and you may feel as though your knee may buckle under your weight. If a ligament tears completely, you may hear a “pop” as it happens.

Medical History and Physical Examination

Your doctor may ask specific questions about your activities, symptoms, and prior injuries. He or she may also want to know whether your symptoms appear immediately after an injury or in the days afterward. This helps the doctor determine if pain is a sign of osteoarthritis of the knee.

Your doctor may ask you to stand and walk to assess whether an injury affects your gait or causes a limp. He or she may also ask you to bend and straighten your leg while you sit on the exam table in order to evaluate the range of motion in the knee.

During a physical exam, your doctor can often determine which type of knee injury you have. He or she may recommend imaging tests to confirm the diagnosis and to distinguish between knee tears that affect the ligaments and those that affect the smooth layer of cartilage composed of two menisci.

X-rays

Your doctor may recommend an X-ray to rule out another cause of the pain, such as a broken bone, arthritis, or bone spurs, which are small bony knobs, also known as osteophytes, that can form in joints when the ends of bones rub together.

An X-ray may also show whether fluid has accumulated around a joint, which is a sign of a sprain or strain. It can also detect loose pieces of bone, which can cause pain.

An X-ray may help your doctor to create a treatment plan to address the injury and ensure that any problem with the alignment of the knee is corrected.

Ultrasound

Doctors at NYU Langone often use ultrasound to diagnose muscle, tendon, and ligament injuries. This is because ultrasound uses high frequency sound waves to produce an often clearer picture of soft tissue, such as muscles and ligaments, compared with X-ray images.

Ultrasound scans are quick and painless. Many of our doctors have ultrasound machines in their offices. Your doctor may also refer you to one of NYU Langone’s musculoskeletal radiologists, our imaging services specialists.

MRI Scans

During an MRI scan, a magnetic field and radio waves are used to create computerized, three-dimensional images of structures in your body. Doctors use MRI scans to examine the ligaments and menisci and to determine the extent of a knee tear. The results of these scans can also determine if more than one structure in the knee is affected.

CT Scans

If you have the symptoms of a sprain, strain, or tear but the muscles, tendons, and ligaments of the knee seem healthy, your doctor may suspect another injury, such as a fracture. A CT scan, which uses multiple X-ray images to create a digital map of the knee, can help your doctor to find very subtle fractures that might otherwise go undetected.