Lecture #18 (Knee Rehab)

Question 1

What are the two joints of the knee?

Answer 1

Patellofemoral joint and the tibio-femoral joint

Question 2

Explain the screw-home mechanism during knee extension.

Answer 2

During the last 30 degrees of knee extension, the tibia externally rotates to allow full extension…in order to come out of extension into flexion, the popliteus contracts

Question 3

What muscles all cross the knee joint? (x7)

Answer 3

Quads, hamstrings, gracilis, sartorius, gastroc, popliteus, and genu articularis (pulls the patella up)

Question 4

What portion of knee extension requires twice as much quad strength due to loss of a mechanical advantage of the patella?

Answer 4

The last 15 degrees of extension

Question 5

What range of flexion causes the peak tibiofemoral shear stress?

Answer 5

28-14 degrees

Question 6

The patella doesn’t contact the femur until what flexion angle(s)?

Answer 6

15-20 degrees of flexion

Question 7

How far does the patella glide?

Answer 7

5-7cm in total

Question 8

What range of flexion produces the greatest compressive forces on the patella?

Answer 8

60-90 degrees of flexion

Question 9

Where are OKC exercise stress the greatest? The lowest?

Answer 9

Greatest= at 0 degrees 
Lowest= at 90 degrees

Question 10

Where are CKC exercise stress the greatest? The lowest?

Answer 10

Greatest= between 30-90 degrees of flexion
Lowest= 0-30 degrees and greater than 90 degrees

Question 11

If you are treating for PFPS, what degree range of flexion should you exercise in for CKC exercises? What about in OKC? Why?

Answer 11

CKC= 0-40 degrees
OKC= greater than 50 degrees
**These angles and ranges produce less lateral patellar motion

Question 12

What are the keys to treating patellar dysfunction? (x6)

Answer 12

• VMO is difficult to activate
• Correct mechanics (avoid valgus collapse)
• use biofeedback or e-stim for patients who don’t have good quad activity
• keep the patella behind the toes when doing closed chain exercises
• avoid heavy open chain work
• stay within the pain-free low joint stress positions

Question 13

WHat are the keys to rehabbing a knee scope? (x

Answer 13

• can be fairly aggressive with progression (but still control swelling)
• avoid twisting (work on knee control)
• meniscal repairs will often have ROM restrictions and weight bearing restrictions
• lateral releases should be treated similar to patellar dysfunction

Question 14

What muscle(s) is(are) important to stretch in a patient with osgood schlatter or patellar tendonitis?

Answer 14

The hamstrings and gastroc

Question 15

What are the three keys to rehabbing MCL and LCL sprains?

Answer 15

• May have to brace through rehab depending on instability (if they were brace during rehab, then wear it when RTP)
• Avoid twisting and varus/valgus stress
• Work on knee control to prevent future injuries

Question 16

What degrees of flexion during OKC exercises place the greatest shear stress on the ACL?

Answer 16

15-30 degrees of flexion

Question 17

What degrees of flexion during CKC exercises place the greatest shear stress on the ACL?

Answer 17

60 degrees

Question 18

What degrees of knee flexion places the greatest stress on the ACL? What position is the greatest for quad strengthening?

Answer 18

The greatest ACL stress comes between 0-40 degrees of flexion, but the best position for quad strengthening is 30 degrees.

Question 19

What are the keys to rehabbing an ACL reconstruction? (x6)

Answer 19

• Follow surgeon’s protocol
• Control swelling for easier ROM
• Maintainn 0 degrees of extension throughout
• Watch for patellar tendonitis in BTB grafts
• Work on gait to avoid bent knee heel strike
• watch for AMI and treat it

Question 20

What knee position places the most stress on the PCL?

Answer 20

60 degrees and greater

Question 21

What ROM should you exercise in to ensure that less stress is placed on the PCL?

Answer 21

0-60 degrees