2. INTRODUCTION
Knee Joint produces Functional shortening and Lengthening of extremity
Knee complex plays a major role in supporting the body in Dynamic and Static
situation
The Knee complex is composed of
TIBIOFEMORAL JOINT
PATELLOFEMORAL JOINT
4. TIBIOFEMORAL JOINT
ARTICULATION:
ON DISTAL FEMUR
Convex, Asymmetric - Medial and Lateral condyle
ON PROXIMAL TIBIA
Concave,Asymmetric,Medial and Lateral Plateau
The FEMORAL CONDYLES are twice as large as length of TIBIAL CONDYLES
5. MENISCI
Fibrocartilaginous Joint Disc
Medial and Lateral Menisci - asymmetric
The two ends are called horns
Coronary ligament attaches the Menisci to Tibial plateau
Transverse ligament joins the two Menisci
Medial Menisci is more fixed and attached to capsule and Medial collateral
ligament. They are less mobile and prone to injury
7. FUNCTIONS OF MENISCI
Stability & Mobility Function
STABILITY:
Deepens articular surface
Keeps the joint surface tight
Distribute the load
MOBILITY:
Reduces friction
8. JOINT CAPSULE & BURSAE
Joint capsule encloses Tibiofemoral and Patellofemoral Joint.
It is large,lax,with many folds
The deep folds of capsule forms the Bursae
Suprapatellar Bursae
Prepatellar Bursae
Infrapatellar Bursae
Subpopleteal Bursae
Gastrocnemius Bursae
9. LIGAMENTS
INTRACAPSULAR LIGAMENT
ANTERIOR CRUCIATE LIGAMENT: Extends superiorly and posteriorly attached to posterior
part of inner aspect of Lateral condyle of Femur.
It is more prone for injury eg. Foot ball players
POSTERIOR CRUCIATE LIGAMENT: Extends superiorly and anteriorly to attach to anterior
portion of inner aspect of Medial femoral condyle
12. LIGAMENTS
MEDIAL COLLATERAL LIGAMENT:(TIBIAL)
Extends from medial Femoral condyle to medial part of proximal Tibia,attaches
with medial meniscus
LATERALCOLLATERALLIGAMENT:(FIBULAR)
Extends from Lateral Femoral condyle to head of Fibula
15. ANATOMIC AXIS
A Line runs along the shaft of the Femur and shaft of Tibia they form angle of 170
to 175 degree
When the angle is less than 165 degree an abnormal condition called GENU
VALGUM,
The medial aspect of knee is subjected to distraction force
When the angle is more than 180 degree an abnormal condition called GENU
VARUM
The medial aspect of knee is subjected to Increase compression loading
16. MOVEMENTS
FLEXION- EXTENSION
Saggital plane,Mediolateral axis
ROTATION
Transverse plane,vertical axis
Flexion active range is 120 degree restricted by contact of posterior muscle,active
insufficiancy
passive range is 130 degree
17. MOVEMENTS
During complete Extension, the Tibial tubercle locks in to intercondylar fossa of
Femur, it is the closed packed position.
ROTATION:
It is not possible when knee in full Extension as ligaments are taught
When Knee in 90 degree Flexion---- Rotation is possible, Lateral rotation is 40
degree and Medial rotation is 30 degree
ABDUCTION can be done passively
18. ARTHROKINEMATICS
FLEXION AND EXTENSION:
During Flexion from full Extension Femoral condyles roll in an posterior direction
with sliding anteriorly. In First part of Flexion consist of Rolling and spinning
During Extension from full Flexion Femoral condyles roll in an anterior direction
with sliding posteriorly. In last few degrees of Extension Femoral condyles Roll and
Spin on Tibia
Pure Rolling will move condyles out
19. LOCKING AND UNLOCKING
The spin of Femur in last few degree of Extension causes a Medial rotation of
Femur on Tibia will keep joint in closed packed position, so Femoral rotation is
called LOCKING or SCREW HOME MECHANISM. The Knee is Unlocked by Lateral
rotation of Femur
In open Kinematic chain Tibia laterally rotates on Femur during last few degrees of
Extension to produce LOCKING. Unlocking by Medial rotation.
20. MUSCLES
EXTENSORS
QUADRICEPS
The efficiency of Quadriceps depends on PATELLA,it increases the moment arm
Supports the body weight
Resist the force of gravity
22. PROBLEMS OF TIBIOFEMORAL JOINT
MEDIAL MENISCUS INJURY:
More common,it is fixed, attached to capsule
ANTERIOR CRUCIATE LIGAMENT INJURY:
More common in foot ball players
GENU VALGUM/GENU VARUM
PREPATELLAR BURSITIS:
Inflammation of Prepatellar bursae,common in workers who kneel and work
25. PATELLO FEMORAL JOINT
Patella is the largest sesamoid bone
ARTICULATION:
Patella is attached to the patellar surface on distal Femur.
During Flexion , from Full Extension patella slides downwards and rest in
intercondylar notch
During Extension,from Full Flexion patella slides upwards
27. Q ANGLE
QUADRICEPS ANGLE( Q ANGLE ):
The angle formed by resultant vector of Quadriceps and the pull of ligamentum
patella
It is found by drawing two lines
1.From ASIS to midpoint of Patella
2.From Tibial tubercle to midpoint of Patella
The normal angle is 15 degree
When the angle is large -----Lateral pull on patella is increased.
29. PROBLEMS OF PATELLOFEMORAL JOINT
PATELLA ALTA:
High riding of patella(elevation),there is lateral stress to patella and instability.
CONDROMALACIA PATELLA:
Softening of articular cartilage of Patellofemoral joint.
Later stage fibrillation and thining of cartilage occurs and subchondral bone
exposed.
32. KNEE FLEXION-EXTENSION ARC
SAGITTAL PLANE
FLEXION
EXTENSION
DIVIDED INTO 3 RANGES
SCREW HOME ARC
FUNCTIONAL ARC
DEEP FLEXION ARC
33. SCREW HOME ARC
5 – 10
HERE KNEE IS LOCKED .
THE FEMUR IS IN NEUTRAL ALIGNMENT WITH THE TIBIA
FEMUR STARTS TO INTERNALLY ROTATE AS THE KNEE IS EXTENDED
34. FUNCTIONAL ARC
10 – 120
EXTERNAL ROTATION OF FEMUR
DURING FLEXION, LATERAL CONDYLE BEGINS TO SLIDE POSTERIORLY WHERE AS
MEDIAL CONDYLE MAINTAIN ITS POSITION ON THE TIBIA
CONSIDERED AS ACTIVE RANGE
35. DEEP FLEXION ARC
120 – 140
FURTHER EXTERNAL ROTATION OF FEMUR
BOTH CONDYLES SLIDE POSTERIORLY
THE ROLLBACK AND SLIDE ACHIEVES FULL FLEXION
CALLED PASSIVE RANGE
36. JOINT REACTION FORCE
THESE FORCE INCREASE WITH KNEE FLEXION ANGLE AND DEPENDS ON WETHER
THE LEG IS IN STANCE OR SWING PHASE
JOINT REACTION FORCE IS MAXIMUM DURING FLEXION
BUT KNEE FLEXION VARIES
20 WALKING IN SMOOTH SURFACE
60 ASCENDING STAIRS
85 DESCENDING STAIRS
