| History: There is surprisingly little pain, while in other cases any movement at all seems to elicit tremendous pain. The joint may be unstable, and the patient often describes crepitus or locking of the joint. History will include cause (mechanism) of the injury; duration, degree, location, character of the pain; and the extent and pattern of knee dysfunction and disuse. Physical exam: A physical exam will often reveal a variety of confirming evidence. Such injury responses as edema, abrasions, lacerations, and dislocation of the patella are readily apparent following a traumatic event. Muscle wasting indicates disuse from a condition that would have occurred several weeks or longer ago. Touching (palpating) and manipulating the joint often reveals such problems as ligament instability, meniscal injuries, or partial displacement of the patella (patellar subluxation). Tests: Modern diagnostic methods, including plain x-ray (radiograph), CT scans, MRI, and arthroscopy permit specific diagnosis of the various injuries that can cause internal derangement in the knee. Plain radiographs are a useful screening tool to assess joint surfaces and bony structures, but only 15% of these films reveal the full nature of the condition (Levy). MRI is used most commonly and allows visualization of the less dense structures such as ligaments, menisci, and tendons. Bone fractures are often better visualized using CT scans. Ultrasound may be helpful in distinguishing other conditions such as cysts, aneurysms, and blood clots (thrombophlebitis), although it would not generally be necessary if MRI were available. Withdrawing (aspirating) and analyzing knee joint fluid (joint effusion) helps diagnose infection and inflammatory arthritis. Arthroscopy is an invasive surgical procedure and is usually done to confirm the diagnosis and treat the problem. |
Source: Medical Disability Advisor