KNEE INJURIES


See also Knee Examination

"Ottowa rules" for when to do an x-ray to r/o fx

98.5% sensitive and 49% specific for knee fractures in a meta-analysis of validation studies, (Ann. Int. med. 140:121, 2004-JW; original study was published in Ann. Emerg. Med 26:405, 1995)

Do x-ray if any of the following are true:

In a study comparing the Ottawa rules with the "Pittsburgh Rule" (x-ray if (< 12yo or > 50yo) + injury involving direct blow, OR if 12-50yo + can't walk 4 weight-bearing steps in ER), Ottawa rule had sens 97% and specificity of 27% for knee fx but Pittsburgh Rule had sensitivity of 99% and specificity of 60% for fx!

Patellar problems

  1. Patellar source of pain divided into "patellar pain syndrome" (chondromalacia, patellofemoral OA) and "patellar instablility" (subluxation or dislocation)
  2. Diagnosis of patellar pain is supported by the following:
  1. No history of trauma
  2. Gradual onset
  3. Chronic patellar use (e.g. knee bends)
  4. Worse on climbing & especially descending stairs
  5. Knee stiffness when moving after prolonged immobility (e.g. leaving movie theater)
  6. Patellar tenderness
  7. Pain on rising from deep knee bend but none at bottom of bend
  8. Pain on "patellar compression test" (press on patella against femur)
Anterior Cruciate Ligament tears Menisceal injuries
Osgood-Schlatter's Disease

aka osteochondrosis of the apophysis of the tibial tubercle

(Sources include Core Content Review of Family Medicine, 2012)