Patellar Instability (knee)

Question 1

what can result in a patellar dislocation

Answer 1

direct blow or sudden twist of knee

Question 2

what direction does the patella virtually always dislocate in

Answer 2

laterally

Question 3

when does the patella usually relocate spontaneously

Answer 3

when the knee is straightened (rarely needs manipulated back into position)

Question 4

what can happen when the patella dislocates

Answer 4

the medial patellofemoral ligament tears and osteochondral fractures may occur as the medial facet of the patella strikes the lateral femoral condyle
(suggested by small opacification on xray)

Question 5

what occurs with characteristic xray appearance

Answer 5

lipohaemarthrosis

Question 6

what are some predisposing factors

Answer 6

• ligamentous laxity
• female gender
• shallow trochlear groove
• gene valgum
• femoral neck anterversion
• high riding patella (patella alta)

Question 7

does the risk of recurrent instability increase or decrease with age

Answer 7

decreases

Question 8

what does physio help to strengthen

Answer 8

quaadriceps

Question 9

what is the risk of a recurrent dislocation after a primary dislocation

Answer 9

10%

Question 10

what can be done if there is frequent recurrent dislocations

Answer 10

tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction with tendon autograft