Knee pain accounts for approximatel...

Knee pain accounts for approximately united third of musculoskeletal problems seen in primary care settings. This complaint is in the greatest degree prevalent in physically active patients, with as many as 54 percent of athletes having one degree of knee pain each year. (1) Knee pain can be a source of significant disability, restricting the ability to work or perform activities of daily living.

The knee is a mingled structure (Figure 1), (2) and its evaluation can instant a challenge to the family physician. The differential diagnosis of knee pain is extensive moreover can be narrowed with a detailed history, a focused physical examination and, when indicated, the selective use of appropriate imaging and laboratory studies. Part I of this two-part article provides a systematic approach to evaluating the knee and part II (3) discusses the differential diagnosis of knee pain.

History

PAIN CHARACTERISTICS

The patient's description of knee pain is helpful in focusing the differential diagnosis. (4) It is important to clarify the characteristics of the pain, including its storm (rapid or insidious), location (anterior, medial, lateral, or posterior knee) duration, severity, and quality (eg stupid sharp, achy). Aggravating and alleviating factors also ne to be identified. If knee pain is caused by means of an acute injury, the physician distresss to know whether the patient was able to continue activity or bear weight after the injury or was forced to cease activities immediately.

MECHANICAL SYMPTOMS

The patient should be asked about mechanical symptoms, as it was as locking, popping, or giving way of the knee A history of locking episodes moves a meniscal tear. A sensation of popping at the time of injury put in mind ofs ligamentous injury, probably complete breach of a ligament (third-degree tear). Episodes of giving way are consistent with about degree of knee instability and may indicate patellar subluxation or ligamentous rupture

EFFUSION

The timing and amount of joint effusion are important directions to the diagnosis. Rapid attack (within two hours) of a large, strained effusion suggests rupture of the anterior cruciate ligament or fracture of the tibial plateau with resultant hemarthrosis, whereas slower attack (24 to 36 hours) of a mild to moderate effusion is consistent with meniscal injury or ligamentous sprain. periodical knee effusion after activity is consistent with meniscal injury.

MECHANISM OF INJURY

The patient should be questioned about specific details of the injury. It is important to know if the patient sustained a direct thump to the knee, if the paw was planted at the time of injury, if the patient was decelerating or stopping pop if the patient was landing from a hop if there was a twisting constituent to the injury, and if hyperextension occurred

A direct misfortune to the knee can cause serious injury. Anterior force applied to the proximal tibia with the knee in flexion (eg when the knee hits the dashboard in an automobile accident) can cause injury to the posterior cruciate ligament. The medial collateral ligament is greatest in number commonly injured as a flow of direct lateral force to the knee (eg clipping in football); this force creates a valgus load upon the knee joint and can be the effect in rupture of the medial collateral ligament. reciprocally a medial blow that creates a varus load can injure the lateral collateral ligament.

Noncontact forces also are an important cause of knee injury. Quick stops and sharp crosss or turns create significant deceleration forces that can sprain or breach the anterior cruciate ligament. Hyperextension can end in injury to the anterior cruciate ligament or posterior cruciate ligament. unexpected twisting or pivoting motions create shear forces that can injure the meniscus. A combination of forces can come into one's head simultaneously, causing injury to multiple structures

MEDICAL HISTORY

A history of knee injury or surgery is important. The patient should be asked about previous attempts to treat knee pain, including the use of medications, supporting devices, and physical therapy. The physician also should ask if the patient has a history of relish pseudogout, rheumatoid arthritis, or other degenerative joint disease.

Physical Examination

INSPECTION AND PALPATION

The physician begins at comparing the painful knee with the asymptomatic knee and inspecting the injured knee for erythema, swelling, bruising, and discoloration. The musculature should be symmetric bilaterally. In particular, the vastus medialis obliquus of the quadriceps should be evaluated to determine if it appears normal or exhibit tos signs of atrophy.

The knee is then palpated and checked for pain, warmth, and effusion. Point tendernes should be sought particularly at the patella, tibial tubercle, patellar tendon, quadriceps tendon, anterolateral and anteromedial joint line, medial joint line, and lateral joint line. Moving the patient's knee within a short arc of motion helps identify the joint lines. Range of motion should be assessed through extending and flexing the knee as far as possible (normal range of motion: extension, cipher degrees; flexion, 135 degrees). (5)