Knee: menial injuries

Question 1

describe the medial meniscus attachments to the knee

Answer 1

• more firmly attached than the lateral meniscus
• semicircular (longer medial femoral condyle)
• semimembranosis attaches to the posterior horn of the meniscus

Question 2

Describe the lateral meniscus attaches to the knee

Answer 2

• patella, meniscal ligament attaches to the anterior horn of the lateral meniscus
• popliteus attaches to the posterior horn of the meniscus

Question 3

What is the function of the meniscus

Answer 3

• shock absorption
• congruency
• increase contact area
• wedge shape in the joint to help dissipate forces/keep condyles from rolling off the plateu
• decrease friction
• lubrication and nutrition: spread synovial fluid
• joint proprioception (has innervation)

Question 4

Contact forces of meniscus and without meniscus

Answer 4

• without an meniscus you have early degeneration due to focusing contact stresses in one area of the joint

Question 5

Meniscal motion

Answer 5

• extension: moves anteriorly (via patella meniscal ligament)
• flexion: move posteriorly (semimebranosis/popliteal)
• rotation: opposite tibial plateau (femoral condyles drag/push it along with it)

Question 6

Which meniscus moves the most

Answer 6

• lateral
• the medial is more firmly attached to the joint

Question 7

Where does the joint get its innervation from/innervation of the knee

Answer 7

• the same nerve the innervates the muscles that cross the joint
• femoral and tibial

Question 8

Blood supply to the meniscus

Answer 8

Red zone: area of blood supply

• medial: outer 1/3
• lateral: outer 1/4
• in the peripheral

White zone: area of little/no blood supply

Question 9

Nerve supply of the meniscus

Answer 9

• outer 1/3 is innervated
• inner 1/3 is less innervated
• localized to the peripheral
• a tear in white zone = might not hurt but can cause a change in the motion of pain during motion

Question 10

Mechanism of injury to a meniscus

Answer 10

• medial: more commonly injured
• compression with rotation

Question 11

Symptoms of a meniscus tear

Answer 11

• joint line tenderness –> sprained coronary ligament
• catching, locking
• giving way
• swelling: slow onset = no bleeding into joint
  **giving is due to the femur catching on the piece thats torn

Question 12

Types of meniscal tears

Answer 12

try to draw and look at slide
- longitudinal –> bucket handle tear
- radial tear –> parrot beak tear
- horizontal tear –> flap tear (shearing force)

Question 13

Conservative management of meniscal tears goals

Answer 13

• reduce pain
• decrease effusion
• increase ROM
• increase strength
• normalize gait
• restore function

Question 14

Management of meniscal tears: arthroscopic meniscectomy

Answer 14

• smooth and shave down the torn part
• tear is in the white zone = poor potential to heal

Question 15

Goals of an arthroscopic meniscectomy

Goals for rehab

Answer 15

• decrease post op pain and effusion
• increase ROM
• increase strength
• normalize function
• worse long term prognosis: taken out the sick absorption

Question 16

Management of meniscal tears: arthroscopic meniscal repair

Answer 16

• red zone tear = largely will heal
• repair and preserve
• slower initial rehab
• NWB for protection (sometimes not with longitudinal tears to hoop stresses)
• NWB depends on where the tear is and what type of tear
• better long term prognosis
• biomechanics function of meniscus
• healing time for repaired area

Question 17

Meniscal transplants

Answer 17

• cadaveric meniscus
• bone plugs anchor horns to tibial platuaes
• usually for people under 50
• average time it lasts = 8 years and most of them have a follow up surgery
• lower the risk of an early TKA

Question 18

Ottowa Knee rule criteria

Answer 18

1. Over 65 should be imaged
2. Tenderness over patella with acute injury
3. Tender over fibular head
4. Can’t flex knee beyond 90 degrees
5. Can’t weight bear for 4 steps after injury
   if any one of these is positive the person should be imaged