ACL Injuries

Why are ACL injuries important clinically?

They are common, often require surgery, and increase risk for early osteoarthritis

About how many ACL injuries occur annually in the US according to Kramer’s slide?

200,000+

What proportion of knee injuries does Kramer’s slide attribute to ACL injuries?

About 50%

What percentage of ACL sprains does Kramer’s slide say require surgery?

About 80%

What long-term joint condition is ACL injury associated with increased risk for?

Osteoarthritis

How much higher is ACL injury incidence in games than practice according to Kramer’s slide?

About 7 times higher

Which female sport did Kramer list as having 4 times more ACL tears?

Basketball

Which female sports did Kramer list as having 2–3 times more ACL tears?

Soccer and gymnastics

What percentage of reconstructed ACL patients returned to some athletic activity on Kramer’s slide?

81%

What percentage regained preinjury competition level?

65%

What percentage of high-level athletes returned to competition?

55%

What approximate reinjury risk did Kramer list after ACL injury?

About 15%

What type of ACL injury mechanism is commonly seen in female athletes?

Non-contact

What type of ACL injury mechanism is commonly seen in male athletes?

Contact

During what activities do ACL injuries often occur?

Jumping, landing, cutting, deceleration, and hyperextension

Why can cutting cause an ACL injury?

It creates rotational and deceleration forces at the knee

Why can hyperextension increase ACL injury risk?

The ACL is at maximal length when the knee is extended

What landing position can place the ACL at increased risk?

Straight-knee landing / hyperextension

Which two clinical tests does Kramer list for ACL diagnosis?

Lachman test and anterior drawer test

How much anterior translation is normal in Kramer’s slide?

About 2–4 mm with a solid end point

What findings suggest ACL injury during Lachman or anterior drawer testing?

Increased anterior translation and a soft end point

What imaging method does Kramer list as most commonly used for ACL injury in the US?

MRI

What MRI sensitivity for ACL injury is listed on Kramer’s slide?

86.5%

What MRI specificity for ACL injury is listed on Kramer’s slide?

95.2%

What are the 3 ACL tear grades listed by Kramer?

Grade 1 partial, Grade 2 partial, Grade 3 complete

What are the 3 tear locations/types listed on Kramer’s ACL tear slide?

Mid-substance, tibial avulsion, femoral avulsion

What structures make up the unhappy triad?

ACL sprain, MCL sprain, medial meniscus tear

What is another name for the unhappy triad?

Terrible triad / O’Donoghue’s triad

What sensation may occur with the unhappy triad?

A feeling of a “pop”

What special finding/test is associated with the unhappy triad on Kramer’s slide?

Pivot shift / positive Macintosh test

What bone contusion pattern may accompany the unhappy triad?

Lateral femur and tibia contusion

What muscle imbalance does Kramer list as an intrinsic ACL risk factor?

Quadriceps-to-hamstring imbalance

What normal quadriceps-to-hamstring ratio does Kramer list?

60:40

What quadriceps-to-hamstring ratio does Kramer list for females?

About 70:30 to 80:20

What hormones does Kramer list as possibly reducing collagen strength?

Estrogen and relaxin

What anatomical ACL risk factors does Kramer list?

Smaller ACL, smaller intercondylar notch, larger Q-angle

What external training factor does Kramer list as an ACL risk factor?

Lower-body strength and training

What neuromuscular factor does Kramer list as an ACL risk factor?

Poor neuromuscular control

What equipment/environment factor does Kramer list as an ACL risk factor?

Footwear and surface interaction

What movement factor does Kramer list as an ACL risk factor?

Biomechanics of jumping and landing

What major treatment approach is shown for severe ACL injury in Kramer’s lecture?

ACL reconstruction

What is a graft harvest in ACL reconstruction?

Tissue is taken for use as the replacement ACL

What happens after graft harvest during ACL reconstruction?

Bone tunnels are drilled and the graft is attached

What broad phase follows ACL reconstruction?

Rehabilitation