Knee Presentations

pittsburgh knee decision rule

1. pt hx blunt trauma or fall

2. inability to bear weight x4 steps immediately and in ED

3. age <12 y/o or >50 yo

indications for radiograph: criteria 1 OR 1 + 2 or 3

ottawa knee decision rule

• TTP head of fibula

• inability to bear weight x4 steps immediately and in ED

• age >/= 55 yrs

• isolated TTP patella

radiograph = any criteria

patellar/quad tendon risk factors

• local steroid injection

• prolonged corticosteroid use

• RA

• lupus

• CT disease

• infectious disease

• arteriosclerosis

• DM

• hyperthyroidism

loss of proteoglycans

matrix reaches certain amount of loss that is irreversible (matrix unable to replenish)

chondral injury

limited response per no inflammatory response

subchondral injury

• extends to blood supply

• fills in with tissue like fibrocartilage

• fibrin clot at 48 hrs

• 2 mos: resembles normal cartilage

• erosive changes observed around 6 mos

what does healing of articular cartilage depend on?

extent of lesion and injury type

how long does it take for hemarthrosis to form in osteochondritis dissecans?

2 hrs

how long does effusion take in meniscus lesion?

6-24 hrs

ligament healing phase 1

acute inflammation & reaction

• acute inflammatory response & hematoma formation

• first 3 days

ligament healing phase 2

repair and regeneration

• fibroblasts produce collagen, matrix disorganized

• 2-3 days post injury - 6 weeks

ligament healing phase 3

remodeling and maturation

• collagen fibers become more parallel/organized

• increased tissue contraction and tensile strength

• >/= 12 months post injury

ligament healing requirements

• disrupted tissue must remain in continuity

• controlled forces necessary to facilitate collagen synthesis (tensile loading)

• protection from harmful stresses on tissues