The Knee Lecture

Question 1

ACL Injuries

Answer 1

• Increased risk if previous reconstruction
• When comparing vulnerability of injury between males
  and females:
• women have a greater risk of injury
• injuries include knee laxity and ACL graft rupture
• Women have less successful outcomes after ACL
  reconstruction

Question 2

Why more likely in females for ACL injuries?

Answer 2

*Category of risk factors:
- Anatomic
- Environmental
- Hormonal
- Biomechanics

*At-risk situation for non-contact ACL: deceleration, cutting or changing directions and landing

*Prior to injury: awkward dynamic body movement and awkward event

Question 3

Why more likely in females for ACL injuries? (extrinsic factors)

Answer 3

*Extrinsic risk factors:
- playing surfaces (grass, turf, floor surfaces)
- type of footwear (shoe-surface interaction, cleat design and type of cleats)
- speed and pivoting (changing directions during deceleration)

Question 4

Why more likely in females for ACL injuries? (intrinsic factors)

Answer 4

• largely genetically mediated
• bone geometry at knee
• malalignment (greater valgus)
• general joint laxity (hormonal influences)

*3-fold increase shown with joint
laxity and hypermobility

• muscle strength differences (Q:H and core) necessary for stabilization
• neuromuscular (females have different knee kinematics on ground
  contact—straight legged jumps)

Question 5

Acute Injuries: SPRAINS

Answer 5

• Medial Collateral Ligament (MCL)
• Mechanism: Force on lateral side of
  knee

*Lateral Collateral Ligament (LCL)
- Less likely to be injured because ITB
provides lateral stability

Question 6

Acute Injuries: Meniscus Tear

Answer 6

• Mechanism: Displaced, trapped, pinched, or crushed between condyles
• Signs/Symptoms
• Pain increased with stairs or squatting
• Clicking or locking (typical)
• The meniscus can be torn in a number of ways:
  1. Entire Inner rim: “Bucket-handle
  Tear”
  2. Flap torn from inner rim
  3. Degenerative type tear where a
  portion of the meniscus is frayed
  and torn in multiple directions

Question 7

Meniscus Tear: Chronic Consequence

Answer 7

• Degenerative tears of the
  meniscus are common with
  aging (osteoarthritis (OA) of the
  knee); no injury, just general
  wear and tear
• For athletes, the constant
  rubbing of the torn meniscus on
  the articular cartilage may
  cause wear and tear on the
  surface, leading to
  degeneration of the joint (bone
  to bone rubbing, early OA)
• ACL rupture associated with
  10-fold increased risk for OA

Question 8

Unhappy triad

Answer 8

• Sprain ACL, MCL, &
  torn medial meniscus
• Mechanism:
• flexion / rotation /
  valgus force
• Direct force against a
  fixed foot

*A lot of pressure as it externally rotates

Question 9

Treatment of ACL injuries

Answer 9

• Initial assessment is crucial
• Swelling will limit ligament assessment

*PRICES

*Bracing and surgery

Question 10

Chronic Anterior Knee Pain

Answer 10

• Patellofemoral area
• pain that occurs at the front and center of the knee
• It refers to many different problems–depends
  on where the pain is located and the
  mechanism of loading

Question 11

Patellofemoral Pain Syndrom

Answer 11

• Most common running injury
• Irritation of the patellofemoral
  joint
• Joint becomes inflamed and
  sore especially with increased
  activity
• Caused by too quick of an
  increase in:
• running distance
• training frequency
• speed
• hill running
• Other factors can play a role:
• Running gait
• How well you recover
• Other sports/activities you
  do
• Lifestyle factors (i.e., sleep
  and stress)
• Common in runners,
  jumpers, skiers, cyclists, and
  soccer players who exercise
  often (repetitive loading!!)
• Symptoms aggravated by
  stairs, jumping, crouching,
  kneeling, quick starts/stops,
  prolonged sitting