1. Structures and Related Common Pathologies of the Knee

2. Functional Requirements of the Knee
Stability and
The knee must be stable enough to withstand high loads
Walking on level surfaces =
Stair climbing =
The knee must transmit loads from the upper body and thigh to the lower leg
Mobile enough to permit wide range of ROM for ADL’s
Walking = 0-65
Climbing stairs 0-83
Squatting to lift object = 0-115

3. Anatomy of the Knee The knee joint is called the tibiofemoral joint
Largest joint in the body
Tibiofemoral joint typically has
Comprised of the femur and tibia that are connected by four strong ligaments that limit motion in any direction
Synovial joint

4. Anatomy of the Knee
Femoral condyles rest on top of tibial surface to form
The patella glides through a special groove formed by the two femoral condyles called the

5. Menisci Menisci are found on the Medial and lateral menisci e join
Horseshoe-shaped pieces of cartilage which increase joint concavity and contact surface
Menisci spread forces out across the joint, transmitting some of the load to the articular cartilage of the tibial plateau
Combination of menisci and articular cartilage of the tibial plateu produce a nearly frictionless gliding surface
The menisci aid in lubrication, nutrition, and shock absorption (decrease joint stress)

6. Lateral and Medial Meniscus

8. Patellar Anatomy
The patella, is embedded in the tendon of quadriceps femoris, and is located anterior to the tibio-femoral articulation

9. Patella Function
The patella is part of the knee joint extensor mechanism and works as a lever to provide a greater mechanical advantage for the muscles that extend the knee

10. Muscles, Nerves, and Blood Vessels
The Extensor Mechanism:
Patella, patellar tendon, quadriceps tendon, and quadriceps muscles
Popliteal Nerve:
Located in back of the knee and travels to the lower leg and foot, supplying sensation and muscle control.
The Popliteal Artery (carries blood to the leg and foot) and Popliteal Vein (carries blood back to the heart).
If the popliteal artery is damaged beyond repair, it is very likely the leg will not be able to survive.

11. Knee Stability
The ligaments, joint capsule and menisci are the “static” stabilizers of the knee
The major ligaments of the knee are:
Anterior Cruciate Ligament (ACL)
Posterior Cruciate Ligament (PCL)
Medial Cruciate Ligament (MCL)
Lateral Collateral Ligament (LCL)

12. Anterior Cruciate Ligament
Attaches on the anterior portion of the tibia in a superior-posterior direction and attaches on the posterior lateral femoral condyle
Acts to limit knee rotation
Resists anterior displacement of the tibia on the femur
Keeps the tibia

13. Posterior Cruciate Ligament
It attaches from the posterior portion of the tibia to the medial condyle of the femur
Resists posterior displacement of the tibia on the femur
Keeps the tibia from

14. Anterior and Posterior Cruciate Ligaments
Named cruciate ligaments because they cross each other (like the limbs of the letter X).
Front of right knee

15. Medial Collateral Ligament
The MCL attaches from the medial condyle of the femur to the medial condyle of the tibia
Works to resist
and external rotation forces

16. Lateral Collateral Ligament
Attaches from the lateral condyle of the femur to the fibula
Works to resist

17. Mechanism of ACL Injury
Most people who rupture their ACL can recall the exact moment at which they felt it pop: changing direction, pivoting or cutting in sports like soccer, landing from a jump in sports such as basketball, or falling while skiing
The 4 "classic" symptoms reported with an ACL tear are:
A "pop" from inside the knee
Knee “giving-away” at the time of injury
Knee swells immediately, or within 12 hours
Hemarthrosis: bleeding in the joint

18. Mechanism of ACL injury
With injury, the tibia slides anteriorly on the femur, causing the knee to "give-way". Most lax at 30, but injuries can occur from 15 -45
When the ACL is ruptured, there is usually damage to other knee structures as well:
Medial or lateral collateral ligaments
Menisci
Women are much more susceptible to ACL injuries than men (Q-Angle)

19. Quadriceps Angle or Q-Angle
Formed by a line drawn from the ASIS to the center of the kneecap, and a line drawn from the center of the knee cap to the Tibial tuberosity.
Normal: Males=10° Females=15

20. Rehabilitation for Cruciate Ligament Injuries
Takes about six months for graft to heal
Hamstring or Patellar Tendon
Focus on closed-chained exercises
Foot is against a surface
Squats, step-ups, lunges
Initially avoid rotational exercises
Priority on re-establishing proprioception

21. Mechanism of PCL Injury
The PCL is susceptible to rupture in the face of any severe, direct blow to the front of the knee while the knee is flexed (such as from "dashboard knee" in a car accident)
The incidence of posterior cruciate ligament injuries is far less common than that of anterior cruciate ligament injuries.

22. Mechanism of MCL Injury
Blow to the outside of the knee
Severe outward twist
A complete rupture, will usually involve the ACL

23. Mechanism of LCL Injury
Blow to the inside of the knee
Severe rotational or direct force
Injuries to the LCL are must less prevalent than those to the MCL
A complete rupture will usually involve the ACL, PCL, Menisci, IT band and Biceps Femoris

24. Rehabilitation for Collateral Ligament Injuries
Takes about six months for graft to heal
Hamstring or Patellar Tendon
Focus on closed-chained exercises
Distal joint is fixed
Squats, step-ups, lunges
Avoid rotational exercises until late in program
Priority on re-establishing proprioception

25. Mechanism of Meniscal Injuries
Meniscal tears and issues are about the most common traumatic lesions of the knee
The usual mechanism of injury is a twisting force on a weight bearing flexed knee.
May be traumatic or degenerative with a mild injury producing the problem.
Menisci penetrated by nerves, but almost no blood vessels
When menisci are torn, there is pain but no bleeding
Torn meniscus does not heal

26. Rehabilitation for Meniscal Injuries
Focus on re-gaining muscular strength and neuromuscular control
Return to activity is relatively quick
Partial menisectomy (six to 14 days)
Repaired meniscus is a little longer (about two months)

27. Patellofemoral Pain Syndrome (PFPS)
Also known as Chondromalacia Patella
Softening and deterioration of the articular cartilage on the back of the patella
May be swelling around the kneecap and a grating sensation when flexing or extending the knee
Characterized by pain in the anterior aspect of the knee, aggravated by knee extension activities such as ascending/descending stairs, squatting, rising from a chair, jumping
May affect one or both knees
Highest incidence is in females
Incidence among athletes >25%.

28. Contributing Factors to Patellofemoral Pain Syndrome
Q-angle
Patella Alta/Baja
Hip Muscle Weakness
Tight IT band
Femoral Adduction and Medial rotation
Overuse/Overload
Vastus Medialis Weakness or imbalances between Vastus Medialis and Vastus Lateralis
Subluxation/Dislocation

29. Patella Alta/Baja Patella Alta: Patella Baja:
Patella positioned higher and creates a greater chance that quads can dislocate the patella
Patella Baja:
Patella positioned lower & tends to lead to ’d compressive forces.

30. Hip Muscle Weakness
Weak musculature or poor neuromuscular control  increased medial rotation and adduction of the hip dynamic activities
Poor motor control may cause changes in pelvic and femoral position  altered contact pressure at the knee.
Decreased muscle endurance may contribute to poor motor control at the hip.
In theory, poor proprioception may impact positioning of the femur

31. Patellofemoral Pain Syndrome Treatment Strategies
Closed chain exercises in pain-free range of motion to strengthening quadriceps/hamstrings
Need to re-establish correct patellar tracking
Stretching

32. Patellofemoral Pain Syndrome Treatment Strategies
Hip Abduction &
External Rotation

33. Patellar Injuries and Other Issues
Patellar Tendon Rupture

34. Patellar Injuries and Other Issues
Osgood-Schlatter
Avulsion fracture at the attachment of the patellar tendon at the tibial tubercule

35. Patellar Injuries and Other Issues
Patellar Subluxation/Dislocation

36. Patellar Injuries and Other Issues
Patellar Fracture

37. Knee Replacement

38. Knee Replacement Rehabilitation
Focus on re-gaining muscular strength, range of motion and neuromuscular control (proprioception)
Exercises
Primarily closed chain
Squats, lunges, step-ups, leg press
Proprioception
Bosu, wobble boards, single leg

39. Knee Stability
The muscles about the knee are important “dynamic” stabilizers.
For optimal knee function, support must come from both the integrity of the static stabilizers & good strength of the dynamic stabilizers
Important mechanoreceptors may get disrupted with injury or surgery
Specialized nerve endings that respond to mechanical pressure or deformation and relay that information centrally in the nervous system
During and after the rehab process, improving knee proprioception and neuromuscular control is imperative.