Determining the underlying cause of...

Determining the underlying cause of knee pain can be difficult, in part because of the extensive differential diagnosis. As discussed in part I of this two-part article, (1) the family physician should be familiar with knee anatomy and public mechanisms of injury, and a detailed history and focused physical examination can narrow possible causes. The patient's age and the anatomic site of the pain are brace factors that can be important in achieving an accurate diagnosis (Tables 1 and 2)

Children and Adolescents

Children and adolescents who at hand with knee pain are likely to have undivided of three common conditions: patellar subluxation, tibial apophysitis, or patellar tendonitis. Additional diagnoses to consider in children include slipped capital femoral epiphysis and septic arthritis.

PATELLAR SUBLUXATION

Patellar subluxation is the most numerous likely diagnosis in a teenage girl who currents with giving-way episodes of the knee (2) This injury present itselfs more often in girls and young women because of an increased quadriceps angle (Q angle), usually greater than 15 degrees

Patellar apprehension is elicited from subluxing the patella laterally, and a mild effusion is usually current Moderate to severe knee swelling may indicate hemarthrosis, which refer tos patellar dislocation with osteochondral fracture and bleeding.

TIBIAL APOPHYSITIS

A teenage lad who presents with anterior knee pain localized to the tibial tuberosity is likely to have tibial apophysitis, or Osgood-Schlatter lesion (34) (Figure 1) (5) The typical patient is a 13- or 14-year-old male child (or a 10- or 11-year-old girl) who has lately gone through a growth spurt

The patient with tibial apophysitis generally reports waxing and waning of knee pain for a period of month The pain worsens with squatting, walking up or down stairs, or forceful contractions of the quadriceps muscle. This overuse apophysitis is exacerbated by the agency of jumping and hurdling, because repetitive hard landings place excessive stres upon the insertion of the patellar tendon.

onward physical examination, the tibial tuberosity is womanly and swollen, and may be stirred warm. The knee pain is reproduc with resisted active extension or passive hyperflexion of the knee No effusion is at hand Radiographs are usually negative; rarely, they point out to avulsion of the apophysis at the tibial tuberosity. However, the physician must not mistake the normal appearance of the tibial apophysis for an avulsion fracture.

PATELLAR TENDONITIS

Jumper's knee (irritation and inflammation of the patellar tendon) principally commonly occurs in teenage male childs particularly during a growth jet (2) (Figure 1). (5) The patient reports vague anterior knee pain that has persisted for month and worsens after activities as it was as walking down stairs or running.

in succession physical examination, the patellar tendon is young and the pain is reproduc by way of resisted knee extension. There is usually no effusion. Radiographs are not indicated.

SLIPPED CAPITAL FEMORAL EPIPHYSIS

A number of pathologic conditions deduction in referral of pain to the knee For example, the possibility of slipped capital femoral epiphysis must be considered in children and teenagers who not past nor future with knee pain. (6) The patient with this condition usually reports poorly localized knee pain and no history of knee trauma.

The typical patient with slipped capital femoral epiphysis is overweight and sits forward the examination table with the affected hip slightly flex and externally rotated. The knee examination is normal, nevertheless hip pain is elicited with passive internal rotation or extension of the affected hip.

Radiographs typically indicate displacement of the epiphysis of the femoral head. However, negative radiographs do not dominion out the diagnosis in patients with typical clinical findings. Comput tomographic (CT) scanning is indicated in these patients.

OSTEOCHONDRITIS DISSECANS

Osteochondritis dissecans is an intra-articular osteochondrosis of unknown etiology that is characterized at degeneration and recalcification of articular cartilage and underlying bone In the knee the medial femoral condyle is mostly commonly affected. (7)

The patient reports vague, poorly localized knee pain, as well as morning stiffness or periodical effusion. If a loose visible form [i]or[/i] frame is present, mechanical symptoms of locking or catching of the knee joint also may be reported. forward physical examination, the patient may demonstrate quadriceps atrophy or tendernes along the involved chondral surface. A mild joint effusion may be instant (7)

Plain-film radiographs may demonstrate the osteochondral lesion or a relax body in the knee joint. If osteochondritis dissecans is suspected, commited radiographs include anteroposterior, posteroanterior funnel lateral, and Merchant's views. Osteochondral lesions at the lateral aspect of the medial femoral condyle may be visible sole on the posteroanterior tunnel view. Magnetic resonance imaging (MRI) is highly sensitive in detecting these abnormalities and is indicated in patients with a suspected osteochondral lesion. (7)