Knee Diagnostics


Causes of knee pain | Understanding symptoms | Diagnostics | Nonsurgical treatments | Surgical options | Joint Replacement | Knee prevention

Diagnosing the Cause of Knee Pain

Diagnosing knee problems can be tricky, partly because of the subjective nature of pain. Orthopedic surgeons during a physician exam will look for outward signs of injury to the knee, such as sudden swelling and deformity.

They will also interview the patient to determine if the pain symptoms came on suddenly (e.g. traumatic injury or fall) or if the symptoms worsened gradually over time. Other tests involve manipulating the knee joint to determine if there is too much play in the joint, or if specific movements worsen pain symptoms.

X-rays are typically taken of the knee from several angles, which can reveal a fracture and signs of arthritis. But because X-rays show only bone, and not soft tissue, an MRI may be needed to reveal ligament problems, meniscus tears and other soft tissue issues.

In many cases, the orthopedic surgeon is playing detective to determine what is causing your knee pain. The goal of a visit to the knee doctor is to determine if the knee pain is caused by ligament strain or joint problems like bone-on-bone abrasion from a cartilage tear.

The orthopedic specialist exam typically involves the following steps:

The medical history

The medical history may include your family as well as your personal story. The reason a doctor asks questions about your siblings or parents is to determine whether inherited conditions, such as arthritis, exist within the family. If so, you may be prone to the same problem. You will be asked questions about how and when you first noticed pain in your knee. This part of the exam may seem tedious, but your answers are crucial. For example, if you reveal that your knee pain occurred precisely when you came down from a rebound and you heard a loud pop . . . the doctor will have a high degree of confidence that you probably tore your anterior cruciate ligament.

The hands-on knee exam

Each maneuver that the knee specialist performs reveals something only to the doctor who has done thousands of such exams. Some of these knee joint movements may be painful. Some movements of the joint can imply a meniscus tear while other movements can confirm a ligament tear.

X-rays and/or MRI diagnostic tests

Unlike X-rays that only show bones clearly, magnetic resonance imaging (MRI) scans reveal the soft tissues, such as the meniscus and tendons. They go beyond the X-ray in what they demonstrate but, because of cost, are used sparingly.

Unlike X-rays, MRI uses the power of magnetic fields to draw images of the internal structures of the body. MRI is a relatively safe test, and in fact, safer than most tests which use radiation. However, a person undergoing an MRI must remain very still for some time while the computer is creating the image.

Diagnostic treatments

In a sense, “diagnostic treatments” may sound like contradictory terms. But there are certain “treatments” that a doctor may try. If they succeed, they may confirm a doctor’s suspicions about the cause of your pain. This can include use of oral medications to reduce inflammation, draining fluid, or injections into the knee joint.

Arthroscopic examination

One tool, both diagnostic and surgical, which has dramatically improved knee care is the arthroscope. Years ago, if a surgeon needed to inspect the knee he or she would have to make a long incision to enter and visually explore the site. Unfortunately, this incision damaged soft tissues and slowed rehabilitation. The arthroscope changed that. Instead of a three-inch incision, knee surgery is now done through small puncture incisions about one to two mm in length.