Orthopaedic surgeons make use of dozens of diagnostic tools every day in the management and treatment of sports injuries. These range from the relatively simple to the unbelievably complex and from free to very expensive. From X-rays to MRIs, orthopaedists use over a century of technology to help visualize the musculoskeletal system to diagnose and treat injuries. First of all it is important to point out that nothing can take the place of a good history and physical examination. It is the sine qua non of medicine and can never be replaced. However, sometimes the examination alone isn’t enough to provide the diagnosis. In these cases, further diagnostic study is needed.
Which study is appropriate is dependent upon the nature of the problem, the availability of diagnostic tools, the personal preference of the doctor, and the economic feasibility of the test, among other things. One of the oldest and simplest diagnostic tools is the X-ray. It has been used for over a hundred years and has become a staple of orthopaedic practice. Few, if any, orthopaedists can function without one in or near their office. X-ray works by placing the patient in between an X-ray tube and specialized film. The X-rays are emitted and travel towards the film. Things that block the radiation from making it to the film cause images to be produced on the film that is of diagnostic significance. X-rays allow doctors to distinguish four shades of gray. For example, air is black and metal (or other high density material) is white. This is because air allows all of the X-rays to make it onto the film, whereas metal blocks them all. Other things visualized on X-ray are soft tissue and fluid. Things like muscle appear one shade of gray and water and other fluids appear another. X-rays are fairly cheap, allow good visualization of bony structures, and are pretty good at allowing for visualization of fractures and the evaluation of the bony portion of joints. Though some soft tissue determinations can be made with X-ray, it certainly doesn’t do the best job of defining soft tissue anatomy. However, X-rays are a good place to start with many problems and may indeed provide the needed answers in many cases.
Sometimes the diagnostic puzzle can’t be solved with X-ray alone. In these cases, other modalities must be used. In the same physics ballpark as X-ray is the CT scan (cat scan is an older term for the same thing). CT scanners also use X-rays but display the information in a different way. Unlike conventional X-rays, which allow doctors to see just four shades of gray, CT allows the differentiation of 16 shades. And although there are more shades, the same principles of density apply (metal and high density substances block the beam and air allows all of it to pass through). The easy way to think of CT scanning is to think of the body as a loaf of bread. The CT scanner makes slices through the body that allow the visualization of different planes of tissue much like taking away successive slices of bread form the feet to the head (or whatever area is being scanned). Though other areas of medicine make more use of CT scans that orthopaedists, they do have a significant role in the treatment of sports conditions. For example, CT scans do an excellent job of defining joint surfaces like the socket of the shoulder and the hip. If there is a question of whether or not the particular surface has been involved in a fracture and plain X-ray films don’t furnish the answer, CT is an excellent choice to provide the solution. Along with other imaging modalities, CT is also used to evaluate the spine. X-rays don’t always provide enough information about the spine to make clinical determinations. CT can be extremely useful in these situations.
With MRI pictures, the structures within the knee that can’t be seen with X-rays can be visualized. The ligaments and cartilages within the knee can be evaluated and their integrity can be assessed. Sometimes in sports medicine, time is of the essence. In these cases when the diagnosis would likely be apparent with time and conservative treatment, but an answer is needed quickly, MRI can help. The injured structures can be visualized immediately and a diagnosis and treatment plan can be formulated immediately after the images are reviewed. MRI is also very useful in the shoulder. Sometimes it is necessary to visualize the rotator cuff tendon to see if there is a full versus partial thickness tear. MRI is fairly good at determining this, which is important since the surgical management can be very different. MRI is the sine qua non of visualizing soft tissue with and around the spinal column. People who’ve experienced much back or neck pain have likely had an MRI scan. Virtually all operations that take place on the back or neck do so after and usually based upon an MRI scan.
MRI also has occasional; uses in the hip, ankle, wrist and elbow. However, since the soft tissues within these joints are more limited and the anatomy can be seen pretty well with explain radiographs, its use is more limited. With all of the wonders of MRI, it should be kept in mind that it’s not perfect. Indeed, MRI can miss a wide variety of clinically significant injuries. An example might be a torn meniscus cartilage within the knee. MRI is between 85 percent and 95 percent sensitive for diagnosing this injury.
Therefore, it is important to let MRI findings obscure the fairly obvious clinical diagnosis. MRI is now a routine used in the diagnosis and treatment of sports medicine conditions. And although it is important and necessary instrument, we shouldn’t lose sight of the fact that most diagnoses are still made the old fashion way with history, physical examination and X-ray.